diff options
Diffstat (limited to 'src/org/apache/commons/logging')
| -rw-r--r-- | src/org/apache/commons/logging/Log.java | 245 | ||||
| -rw-r--r-- | src/org/apache/commons/logging/LogConfigurationException.java | 97 | ||||
| -rw-r--r-- | src/org/apache/commons/logging/LogFactory.java | 1740 | ||||
| -rw-r--r-- | src/org/apache/commons/logging/LogSource.java | 261 | ||||
| -rw-r--r-- | src/org/apache/commons/logging/impl/Jdk14Logger.java | 303 | ||||
| -rw-r--r-- | src/org/apache/commons/logging/impl/LogFactoryImpl.java | 1400 | ||||
| -rw-r--r-- | src/org/apache/commons/logging/impl/NoOpLog.java | 106 | ||||
| -rw-r--r-- | src/org/apache/commons/logging/impl/SimpleLog.java | 709 | ||||
| -rw-r--r-- | src/org/apache/commons/logging/impl/WeakHashtable.java | 478 | ||||
| -rw-r--r-- | src/org/apache/commons/logging/impl/package.html | 21 | ||||
| -rw-r--r-- | src/org/apache/commons/logging/package.html | 254 |
11 files changed, 5614 insertions, 0 deletions
diff --git a/src/org/apache/commons/logging/Log.java b/src/org/apache/commons/logging/Log.java new file mode 100644 index 0000000..9203f3f --- /dev/null +++ b/src/org/apache/commons/logging/Log.java @@ -0,0 +1,245 @@ +/* + * Copyright 2001-2004 The Apache Software Foundation. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + + +package org.apache.commons.logging; + +/** + * <p>A simple logging interface abstracting logging APIs. In order to be + * instantiated successfully by {@link LogFactory}, classes that implement + * this interface must have a constructor that takes a single String + * parameter representing the "name" of this Log.</p> + * + * <p> The six logging levels used by <code>Log</code> are (in order): + * <ol> + * <li>trace (the least serious)</li> + * <li>debug</li> + * <li>info</li> + * <li>warn</li> + * <li>error</li> + * <li>fatal (the most serious)</li> + * </ol> + * The mapping of these log levels to the concepts used by the underlying + * logging system is implementation dependent. + * The implemention should ensure, though, that this ordering behaves + * as expected.</p> + * + * <p>Performance is often a logging concern. + * By examining the appropriate property, + * a component can avoid expensive operations (producing information + * to be logged).</p> + * + * <p> For example, + * <code><pre> + * if (log.isDebugEnabled()) { + * ... do something expensive ... + * log.debug(theResult); + * } + * </pre></code> + * </p> + * + * <p>Configuration of the underlying logging system will generally be done + * external to the Logging APIs, through whatever mechanism is supported by + * that system.</p> + * + * @author <a href="mailto:sanders@apache.org">Scott Sanders</a> + * @author Rod Waldhoff + * @version $Id: Log.java 381838 2006-02-28 23:57:11Z skitching $ + */ +public interface Log { + + + // ----------------------------------------------------- Logging Properties + + + /** + * <p> Is debug logging currently enabled? </p> + * + * <p> Call this method to prevent having to perform expensive operations + * (for example, <code>String</code> concatenation) + * when the log level is more than debug. </p> + * + * @return true if debug is enabled in the underlying logger. + */ + public boolean isDebugEnabled(); + + + /** + * <p> Is error logging currently enabled? </p> + * + * <p> Call this method to prevent having to perform expensive operations + * (for example, <code>String</code> concatenation) + * when the log level is more than error. </p> + * + * @return true if error is enabled in the underlying logger. + */ + public boolean isErrorEnabled(); + + + /** + * <p> Is fatal logging currently enabled? </p> + * + * <p> Call this method to prevent having to perform expensive operations + * (for example, <code>String</code> concatenation) + * when the log level is more than fatal. </p> + * + * @return true if fatal is enabled in the underlying logger. + */ + public boolean isFatalEnabled(); + + + /** + * <p> Is info logging currently enabled? </p> + * + * <p> Call this method to prevent having to perform expensive operations + * (for example, <code>String</code> concatenation) + * when the log level is more than info. </p> + * + * @return true if info is enabled in the underlying logger. + */ + public boolean isInfoEnabled(); + + + /** + * <p> Is trace logging currently enabled? </p> + * + * <p> Call this method to prevent having to perform expensive operations + * (for example, <code>String</code> concatenation) + * when the log level is more than trace. </p> + * + * @return true if trace is enabled in the underlying logger. + */ + public boolean isTraceEnabled(); + + + /** + * <p> Is warn logging currently enabled? </p> + * + * <p> Call this method to prevent having to perform expensive operations + * (for example, <code>String</code> concatenation) + * when the log level is more than warn. </p> + * + * @return true if warn is enabled in the underlying logger. + */ + public boolean isWarnEnabled(); + + + // -------------------------------------------------------- Logging Methods + + + /** + * <p> Log a message with trace log level. </p> + * + * @param message log this message + */ + public void trace(Object message); + + + /** + * <p> Log an error with trace log level. </p> + * + * @param message log this message + * @param t log this cause + */ + public void trace(Object message, Throwable t); + + + /** + * <p> Log a message with debug log level. </p> + * + * @param message log this message + */ + public void debug(Object message); + + + /** + * <p> Log an error with debug log level. </p> + * + * @param message log this message + * @param t log this cause + */ + public void debug(Object message, Throwable t); + + + /** + * <p> Log a message with info log level. </p> + * + * @param message log this message + */ + public void info(Object message); + + + /** + * <p> Log an error with info log level. </p> + * + * @param message log this message + * @param t log this cause + */ + public void info(Object message, Throwable t); + + + /** + * <p> Log a message with warn log level. </p> + * + * @param message log this message + */ + public void warn(Object message); + + + /** + * <p> Log an error with warn log level. </p> + * + * @param message log this message + * @param t log this cause + */ + public void warn(Object message, Throwable t); + + + /** + * <p> Log a message with error log level. </p> + * + * @param message log this message + */ + public void error(Object message); + + + /** + * <p> Log an error with error log level. </p> + * + * @param message log this message + * @param t log this cause + */ + public void error(Object message, Throwable t); + + + /** + * <p> Log a message with fatal log level. </p> + * + * @param message log this message + */ + public void fatal(Object message); + + + /** + * <p> Log an error with fatal log level. </p> + * + * @param message log this message + * @param t log this cause + */ + public void fatal(Object message, Throwable t); + + +} diff --git a/src/org/apache/commons/logging/LogConfigurationException.java b/src/org/apache/commons/logging/LogConfigurationException.java new file mode 100644 index 0000000..b34387b --- /dev/null +++ b/src/org/apache/commons/logging/LogConfigurationException.java @@ -0,0 +1,97 @@ +/* + * Copyright 2001-2004 The Apache Software Foundation. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.commons.logging; + + +/** + * <p>An exception that is thrown only if a suitable <code>LogFactory</code> + * or <code>Log</code> instance cannot be created by the corresponding + * factory methods.</p> + * + * @author Craig R. McClanahan + * @version $Revision: 155426 $ $Date: 2005-02-26 13:10:49 +0000 (Sat, 26 Feb 2005) $ + */ + +public class LogConfigurationException extends RuntimeException { + + + /** + * Construct a new exception with <code>null</code> as its detail message. + */ + public LogConfigurationException() { + + super(); + + } + + + /** + * Construct a new exception with the specified detail message. + * + * @param message The detail message + */ + public LogConfigurationException(String message) { + + super(message); + + } + + + /** + * Construct a new exception with the specified cause and a derived + * detail message. + * + * @param cause The underlying cause + */ + public LogConfigurationException(Throwable cause) { + + this((cause == null) ? null : cause.toString(), cause); + + } + + + /** + * Construct a new exception with the specified detail message and cause. + * + * @param message The detail message + * @param cause The underlying cause + */ + public LogConfigurationException(String message, Throwable cause) { + + super(message + " (Caused by " + cause + ")"); + this.cause = cause; // Two-argument version requires JDK 1.4 or later + + } + + + /** + * The underlying cause of this exception. + */ + protected Throwable cause = null; + + + /** + * Return the underlying cause of this exception (if any). + */ + public Throwable getCause() { + + return (this.cause); + + } + + +} diff --git a/src/org/apache/commons/logging/LogFactory.java b/src/org/apache/commons/logging/LogFactory.java new file mode 100644 index 0000000..107d0f7 --- /dev/null +++ b/src/org/apache/commons/logging/LogFactory.java @@ -0,0 +1,1740 @@ +/* + * Copyright 2001-2006 The Apache Software Foundation. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.commons.logging; + + +import java.io.BufferedReader; +import java.io.FileOutputStream; +import java.io.IOException; +import java.io.InputStream; +import java.io.InputStreamReader; +import java.io.PrintStream; +import java.lang.reflect.InvocationTargetException; +import java.lang.reflect.Method; +import java.net.URL; +import java.security.AccessController; +import java.security.PrivilegedAction; +import java.util.Enumeration; +import java.util.Hashtable; +import java.util.Properties; + + +/** + * <p>Factory for creating {@link Log} instances, with discovery and + * configuration features similar to that employed by standard Java APIs + * such as JAXP.</p> + * + * <p><strong>IMPLEMENTATION NOTE</strong> - This implementation is heavily + * based on the SAXParserFactory and DocumentBuilderFactory implementations + * (corresponding to the JAXP pluggability APIs) found in Apache Xerces.</p> + * + * @author Craig R. McClanahan + * @author Costin Manolache + * @author Richard A. Sitze + * @version $Revision: 399431 $ $Date: 2006-05-03 21:58:34 +0100 (Wed, 03 May 2006) $ + */ + +public abstract class LogFactory { + + + // ----------------------------------------------------- Manifest Constants + + /** + * The name (<code>priority</code>) of the key in the config file used to + * specify the priority of that particular config file. The associated value + * is a floating-point number; higher values take priority over lower values. + */ + public static final String PRIORITY_KEY = "priority"; + + /** + * The name (<code>use_tccl</code>) of the key in the config file used + * to specify whether logging classes should be loaded via the thread + * context class loader (TCCL), or not. By default, the TCCL is used. + */ + public static final String TCCL_KEY = "use_tccl"; + + /** + * The name (<code>org.apache.commons.logging.LogFactory</code>) of the property + * used to identify the LogFactory implementation + * class name. This can be used as a system property, or as an entry in a + * configuration properties file. + */ + public static final String FACTORY_PROPERTY = + "org.apache.commons.logging.LogFactory"; + + /** + * The fully qualified class name of the fallback <code>LogFactory</code> + * implementation class to use, if no other can be found. + */ + public static final String FACTORY_DEFAULT = + "org.apache.commons.logging.impl.LogFactoryImpl"; + + /** + * The name (<code>commons-logging.properties</code>) of the properties file to search for. + */ + public static final String FACTORY_PROPERTIES = + "commons-logging.properties"; + + /** + * JDK1.3+ <a href="http://java.sun.com/j2se/1.3/docs/guide/jar/jar.html#Service%20Provider"> + * 'Service Provider' specification</a>. + * + */ + protected static final String SERVICE_ID = + "META-INF/services/org.apache.commons.logging.LogFactory"; + + /** + * The name (<code>org.apache.commons.logging.diagnostics.dest</code>) + * of the property used to enable internal commons-logging + * diagnostic output, in order to get information on what logging + * implementations are being discovered, what classloaders they + * are loaded through, etc. + * <p> + * If a system property of this name is set then the value is + * assumed to be the name of a file. The special strings + * STDOUT or STDERR (case-sensitive) indicate output to + * System.out and System.err respectively. + * <p> + * Diagnostic logging should be used only to debug problematic + * configurations and should not be set in normal production use. + */ + public static final String DIAGNOSTICS_DEST_PROPERTY = + "org.apache.commons.logging.diagnostics.dest"; + + /** + * When null (the usual case), no diagnostic output will be + * generated by LogFactory or LogFactoryImpl. When non-null, + * interesting events will be written to the specified object. + */ + private static PrintStream diagnosticsStream = null; + + /** + * A string that gets prefixed to every message output by the + * logDiagnostic method, so that users can clearly see which + * LogFactory class is generating the output. + */ + private static String diagnosticPrefix; + + /** + * <p>Setting this system property + * (<code>org.apache.commons.logging.LogFactory.HashtableImpl</code>) + * value allows the <code>Hashtable</code> used to store + * classloaders to be substituted by an alternative implementation. + * </p> + * <p> + * <strong>Note:</strong> <code>LogFactory</code> will print: + * <code><pre> + * [ERROR] LogFactory: Load of custom hashtable failed</em> + * </pre></code> + * to system error and then continue using a standard Hashtable. + * </p> + * <p> + * <strong>Usage:</strong> Set this property when Java is invoked + * and <code>LogFactory</code> will attempt to load a new instance + * of the given implementation class. + * For example, running the following ant scriplet: + * <code><pre> + * <java classname="${test.runner}" fork="yes" failonerror="${test.failonerror}"> + * ... + * <sysproperty + * key="org.apache.commons.logging.LogFactory.HashtableImpl" + * value="org.apache.commons.logging.AltHashtable"/> + * </java> + * </pre></code> + * will mean that <code>LogFactory</code> will load an instance of + * <code>org.apache.commons.logging.AltHashtable</code>. + * </p> + * <p> + * A typical use case is to allow a custom + * Hashtable implementation using weak references to be substituted. + * This will allow classloaders to be garbage collected without + * the need to release them (on 1.3+ JVMs only, of course ;) + * </p> + */ + public static final String HASHTABLE_IMPLEMENTATION_PROPERTY = + "org.apache.commons.logging.LogFactory.HashtableImpl"; + /** Name used to load the weak hashtable implementation by names */ + private static final String WEAK_HASHTABLE_CLASSNAME = + "org.apache.commons.logging.impl.WeakHashtable"; + + /** + * A reference to the classloader that loaded this class. This is the + * same as LogFactory.class.getClassLoader(). However computing this + * value isn't quite as simple as that, as we potentially need to use + * AccessControllers etc. It's more efficient to compute it once and + * cache it here. + */ + private static ClassLoader thisClassLoader; + + // ----------------------------------------------------------- Constructors + + + /** + * Protected constructor that is not available for public use. + */ + protected LogFactory() { + } + + // --------------------------------------------------------- Public Methods + + + /** + * Return the configuration attribute with the specified name (if any), + * or <code>null</code> if there is no such attribute. + * + * @param name Name of the attribute to return + */ + public abstract Object getAttribute(String name); + + + /** + * Return an array containing the names of all currently defined + * configuration attributes. If there are no such attributes, a zero + * length array is returned. + */ + public abstract String[] getAttributeNames(); + + + /** + * Convenience method to derive a name from the specified class and + * call <code>getInstance(String)</code> with it. + * + * @param clazz Class for which a suitable Log name will be derived + * + * @exception LogConfigurationException if a suitable <code>Log</code> + * instance cannot be returned + */ + public abstract Log getInstance(Class clazz) + throws LogConfigurationException; + + + /** + * <p>Construct (if necessary) and return a <code>Log</code> instance, + * using the factory's current set of configuration attributes.</p> + * + * <p><strong>NOTE</strong> - Depending upon the implementation of + * the <code>LogFactory</code> you are using, the <code>Log</code> + * instance you are returned may or may not be local to the current + * application, and may or may not be returned again on a subsequent + * call with the same name argument.</p> + * + * @param name Logical name of the <code>Log</code> instance to be + * returned (the meaning of this name is only known to the underlying + * logging implementation that is being wrapped) + * + * @exception LogConfigurationException if a suitable <code>Log</code> + * instance cannot be returned + */ + public abstract Log getInstance(String name) + throws LogConfigurationException; + + + /** + * Release any internal references to previously created {@link Log} + * instances returned by this factory. This is useful in environments + * like servlet containers, which implement application reloading by + * throwing away a ClassLoader. Dangling references to objects in that + * class loader would prevent garbage collection. + */ + public abstract void release(); + + + /** + * Remove any configuration attribute associated with the specified name. + * If there is no such attribute, no action is taken. + * + * @param name Name of the attribute to remove + */ + public abstract void removeAttribute(String name); + + + /** + * Set the configuration attribute with the specified name. Calling + * this with a <code>null</code> value is equivalent to calling + * <code>removeAttribute(name)</code>. + * + * @param name Name of the attribute to set + * @param value Value of the attribute to set, or <code>null</code> + * to remove any setting for this attribute + */ + public abstract void setAttribute(String name, Object value); + + + // ------------------------------------------------------- Static Variables + + + /** + * The previously constructed <code>LogFactory</code> instances, keyed by + * the <code>ClassLoader</code> with which it was created. + */ + protected static Hashtable factories = null; + + /** + * Prevously constructed <code>LogFactory</code> instance as in the + * <code>factories</code> map, but for the case where + * <code>getClassLoader</code> returns <code>null</code>. + * This can happen when: + * <ul> + * <li>using JDK1.1 and the calling code is loaded via the system + * classloader (very common)</li> + * <li>using JDK1.2+ and the calling code is loaded via the boot + * classloader (only likely for embedded systems work).</li> + * </ul> + * Note that <code>factories</code> is a <i>Hashtable</i> (not a HashMap), + * and hashtables don't allow null as a key. + */ + protected static LogFactory nullClassLoaderFactory = null; + + /** + * Create the hashtable which will be used to store a map of + * (context-classloader -> logfactory-object). Version 1.2+ of Java + * supports "weak references", allowing a custom Hashtable class + * to be used which uses only weak references to its keys. Using weak + * references can fix memory leaks on webapp unload in some cases (though + * not all). Version 1.1 of Java does not support weak references, so we + * must dynamically determine which we are using. And just for fun, this + * code also supports the ability for a system property to specify an + * arbitrary Hashtable implementation name. + * <p> + * Note that the correct way to ensure no memory leaks occur is to ensure + * that LogFactory.release(contextClassLoader) is called whenever a + * webapp is undeployed. + */ + private static final Hashtable createFactoryStore() { + Hashtable result = null; + String storeImplementationClass + = System.getProperty(HASHTABLE_IMPLEMENTATION_PROPERTY); + if (storeImplementationClass == null) { + storeImplementationClass = WEAK_HASHTABLE_CLASSNAME; + } + try { + Class implementationClass = Class.forName(storeImplementationClass); + result = (Hashtable) implementationClass.newInstance(); + + } catch (Throwable t) { + // ignore + if (!WEAK_HASHTABLE_CLASSNAME.equals(storeImplementationClass)) { + // if the user's trying to set up a custom implementation, give a clue + if (isDiagnosticsEnabled()) { + // use internal logging to issue the warning + logDiagnostic("[ERROR] LogFactory: Load of custom hashtable failed"); + } else { + // we *really* want this output, even if diagnostics weren't + // explicitly enabled by the user. + System.err.println("[ERROR] LogFactory: Load of custom hashtable failed"); + } + } + } + if (result == null) { + result = new Hashtable(); + } + return result; + } + + + // --------------------------------------------------------- Static Methods + + /** + * <p>Construct (if necessary) and return a <code>LogFactory</code> + * instance, using the following ordered lookup procedure to determine + * the name of the implementation class to be loaded.</p> + * <ul> + * <li>The <code>org.apache.commons.logging.LogFactory</code> system + * property.</li> + * <li>The JDK 1.3 Service Discovery mechanism</li> + * <li>Use the properties file <code>commons-logging.properties</code> + * file, if found in the class path of this class. The configuration + * file is in standard <code>java.util.Properties</code> format and + * contains the fully qualified name of the implementation class + * with the key being the system property defined above.</li> + * <li>Fall back to a default implementation class + * (<code>org.apache.commons.logging.impl.LogFactoryImpl</code>).</li> + * </ul> + * + * <p><em>NOTE</em> - If the properties file method of identifying the + * <code>LogFactory</code> implementation class is utilized, all of the + * properties defined in this file will be set as configuration attributes + * on the corresponding <code>LogFactory</code> instance.</p> + * + * <p><em>NOTE</em> - In a multithreaded environment it is possible + * that two different instances will be returned for the same + * classloader environment. + * </p> + * + * @exception LogConfigurationException if the implementation class is not + * available or cannot be instantiated. + */ + public static LogFactory getFactory() throws LogConfigurationException { + // Identify the class loader we will be using + ClassLoader contextClassLoader = getContextClassLoader(); + + if (contextClassLoader == null) { + // This is an odd enough situation to report about. This + // output will be a nuisance on JDK1.1, as the system + // classloader is null in that environment. + if (isDiagnosticsEnabled()) { + logDiagnostic("Context classloader is null."); + } + } + + // Return any previously registered factory for this class loader + LogFactory factory = getCachedFactory(contextClassLoader); + if (factory != null) { + return factory; + } + + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] LogFactory implementation requested for the first time for context classloader " + + objectId(contextClassLoader)); + logHierarchy("[LOOKUP] ", contextClassLoader); + } + + // Load properties file. + // + // If the properties file exists, then its contents are used as + // "attributes" on the LogFactory implementation class. One particular + // property may also control which LogFactory concrete subclass is + // used, but only if other discovery mechanisms fail.. + // + // As the properties file (if it exists) will be used one way or + // another in the end we may as well look for it first. + + Properties props = getConfigurationFile(contextClassLoader, FACTORY_PROPERTIES); + + // Determine whether we will be using the thread context class loader to + // load logging classes or not by checking the loaded properties file (if any). + ClassLoader baseClassLoader = contextClassLoader; + if (props != null) { + String useTCCLStr = props.getProperty(TCCL_KEY); + if (useTCCLStr != null) { + // The Boolean.valueOf(useTCCLStr).booleanValue() formulation + // is required for Java 1.2 compatability. + if (Boolean.valueOf(useTCCLStr).booleanValue() == false) { + // Don't use current context classloader when locating any + // LogFactory or Log classes, just use the class that loaded + // this abstract class. When this class is deployed in a shared + // classpath of a container, it means webapps cannot deploy their + // own logging implementations. It also means that it is up to the + // implementation whether to load library-specific config files + // from the TCCL or not. + baseClassLoader = thisClassLoader; + } + } + } + + // Determine which concrete LogFactory subclass to use. + // First, try a global system property + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] Looking for system property [" + FACTORY_PROPERTY + + "] to define the LogFactory subclass to use..."); + } + + try { + String factoryClass = System.getProperty(FACTORY_PROPERTY); + if (factoryClass != null) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] Creating an instance of LogFactory class '" + factoryClass + + "' as specified by system property " + FACTORY_PROPERTY); + } + + factory = newFactory(factoryClass, baseClassLoader, contextClassLoader); + } else { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] No system property [" + FACTORY_PROPERTY + + "] defined."); + } + } + } catch (SecurityException e) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] A security exception occurred while trying to create an" + + " instance of the custom factory class" + + ": [" + e.getMessage().trim() + + "]. Trying alternative implementations..."); + } + ; // ignore + } catch(RuntimeException e) { + // This is not consistent with the behaviour when a bad LogFactory class is + // specified in a services file. + // + // One possible exception that can occur here is a ClassCastException when + // the specified class wasn't castable to this LogFactory type. + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] An exception occurred while trying to create an" + + " instance of the custom factory class" + + ": [" + e.getMessage().trim() + + "] as specified by a system property."); + } + throw e; + } + + + // Second, try to find a service by using the JDK1.3 class + // discovery mechanism, which involves putting a file with the name + // of an interface class in the META-INF/services directory, where the + // contents of the file is a single line specifying a concrete class + // that implements the desired interface. + + if (factory == null) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] Looking for a resource file of name [" + SERVICE_ID + + "] to define the LogFactory subclass to use..."); + } + try { + InputStream is = getResourceAsStream(contextClassLoader, + SERVICE_ID); + + if( is != null ) { + // This code is needed by EBCDIC and other strange systems. + // It's a fix for bugs reported in xerces + BufferedReader rd; + try { + rd = new BufferedReader(new InputStreamReader(is, "UTF-8")); + } catch (java.io.UnsupportedEncodingException e) { + rd = new BufferedReader(new InputStreamReader(is)); + } + + String factoryClassName = rd.readLine(); + rd.close(); + + if (factoryClassName != null && + ! "".equals(factoryClassName)) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] Creating an instance of LogFactory class " + factoryClassName + + " as specified by file '" + SERVICE_ID + + "' which was present in the path of the context" + + " classloader."); + } + factory = newFactory(factoryClassName, baseClassLoader, contextClassLoader ); + } + } else { + // is == null + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] No resource file with name '" + SERVICE_ID + + "' found."); + } + } + } catch( Exception ex ) { + // note: if the specified LogFactory class wasn't compatible with LogFactory + // for some reason, a ClassCastException will be caught here, and attempts will + // continue to find a compatible class. + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] A security exception occurred while trying to create an" + + " instance of the custom factory class" + + ": [" + ex.getMessage().trim() + + "]. Trying alternative implementations..."); + } + ; // ignore + } + } + + + // Third try looking into the properties file read earlier (if found) + + if (factory == null) { + if (props != null) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] Looking in properties file for entry with key '" + + FACTORY_PROPERTY + + "' to define the LogFactory subclass to use..."); + } + String factoryClass = props.getProperty(FACTORY_PROPERTY); + if (factoryClass != null) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] Properties file specifies LogFactory subclass '" + + factoryClass + "'"); + } + factory = newFactory(factoryClass, baseClassLoader, contextClassLoader); + + // TODO: think about whether we need to handle exceptions from newFactory + } else { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] Properties file has no entry specifying LogFactory subclass."); + } + } + } else { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] No properties file available to determine" + + " LogFactory subclass from.."); + } + } + } + + + // Fourth, try the fallback implementation class + + if (factory == null) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] Loading the default LogFactory implementation '" + FACTORY_DEFAULT + + "' via the same classloader that loaded this LogFactory" + + " class (ie not looking in the context classloader)."); + } + + // Note: unlike the above code which can try to load custom LogFactory + // implementations via the TCCL, we don't try to load the default LogFactory + // implementation via the context classloader because: + // * that can cause problems (see comments in newFactory method) + // * no-one should be customising the code of the default class + // Yes, we do give up the ability for the child to ship a newer + // version of the LogFactoryImpl class and have it used dynamically + // by an old LogFactory class in the parent, but that isn't + // necessarily a good idea anyway. + factory = newFactory(FACTORY_DEFAULT, thisClassLoader, contextClassLoader); + } + + if (factory != null) { + /** + * Always cache using context class loader. + */ + cacheFactory(contextClassLoader, factory); + + if( props!=null ) { + Enumeration names = props.propertyNames(); + while (names.hasMoreElements()) { + String name = (String) names.nextElement(); + String value = props.getProperty(name); + factory.setAttribute(name, value); + } + } + } + + return factory; + } + + + /** + * Convenience method to return a named logger, without the application + * having to care about factories. + * + * @param clazz Class from which a log name will be derived + * + * @exception LogConfigurationException if a suitable <code>Log</code> + * instance cannot be returned + */ + public static Log getLog(Class clazz) + throws LogConfigurationException { + + // BEGIN android-added + return getLog(clazz.getName()); + // END android-added + // BEGIN android-deleted + //return (getFactory().getInstance(clazz)); + // END android-deleted + + } + + + /** + * Convenience method to return a named logger, without the application + * having to care about factories. + * + * @param name Logical name of the <code>Log</code> instance to be + * returned (the meaning of this name is only known to the underlying + * logging implementation that is being wrapped) + * + * @exception LogConfigurationException if a suitable <code>Log</code> + * instance cannot be returned + */ + public static Log getLog(String name) + throws LogConfigurationException { + + // BEGIN android-added + return new org.apache.commons.logging.impl.Jdk14Logger(name); + // END android-added + // BEGIN android-deleted + //return (getFactory().getInstance(name)); + // END android-deleted + + } + + + /** + * Release any internal references to previously created {@link LogFactory} + * instances that have been associated with the specified class loader + * (if any), after calling the instance method <code>release()</code> on + * each of them. + * + * @param classLoader ClassLoader for which to release the LogFactory + */ + public static void release(ClassLoader classLoader) { + + if (isDiagnosticsEnabled()) { + logDiagnostic("Releasing factory for classloader " + objectId(classLoader)); + } + synchronized (factories) { + if (classLoader == null) { + if (nullClassLoaderFactory != null) { + nullClassLoaderFactory.release(); + nullClassLoaderFactory = null; + } + } else { + LogFactory factory = (LogFactory) factories.get(classLoader); + if (factory != null) { + factory.release(); + factories.remove(classLoader); + } + } + } + + } + + + /** + * Release any internal references to previously created {@link LogFactory} + * instances, after calling the instance method <code>release()</code> on + * each of them. This is useful in environments like servlet containers, + * which implement application reloading by throwing away a ClassLoader. + * Dangling references to objects in that class loader would prevent + * garbage collection. + */ + public static void releaseAll() { + + if (isDiagnosticsEnabled()) { + logDiagnostic("Releasing factory for all classloaders."); + } + synchronized (factories) { + Enumeration elements = factories.elements(); + while (elements.hasMoreElements()) { + LogFactory element = (LogFactory) elements.nextElement(); + element.release(); + } + factories.clear(); + + if (nullClassLoaderFactory != null) { + nullClassLoaderFactory.release(); + nullClassLoaderFactory = null; + } + } + + } + + + // ------------------------------------------------------ Protected Methods + + /** + * Safely get access to the classloader for the specified class. + * <p> + * Theoretically, calling getClassLoader can throw a security exception, + * and so should be done under an AccessController in order to provide + * maximum flexibility. However in practice people don't appear to use + * security policies that forbid getClassLoader calls. So for the moment + * all code is written to call this method rather than Class.getClassLoader, + * so that we could put AccessController stuff in this method without any + * disruption later if we need to. + * <p> + * Even when using an AccessController, however, this method can still + * throw SecurityException. Commons-logging basically relies on the + * ability to access classloaders, ie a policy that forbids all + * classloader access will also prevent commons-logging from working: + * currently this method will throw an exception preventing the entire app + * from starting up. Maybe it would be good to detect this situation and + * just disable all commons-logging? Not high priority though - as stated + * above, security policies that prevent classloader access aren't common. + * + * @since 1.1 + */ + protected static ClassLoader getClassLoader(Class clazz) { + try { + return clazz.getClassLoader(); + } catch(SecurityException ex) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "Unable to get classloader for class '" + clazz + + "' due to security restrictions - " + ex.getMessage()); + } + throw ex; + } + } + + /** + * Calls LogFactory.directGetContextClassLoader under the control of an + * AccessController class. This means that java code running under a + * security manager that forbids access to ClassLoaders will still work + * if this class is given appropriate privileges, even when the caller + * doesn't have such privileges. Without using an AccessController, the + * the entire call stack must have the privilege before the call is + * allowed. + * + * @return the context classloader associated with the current thread, + * or null if security doesn't allow it. + * + * @throws LogConfigurationException if there was some weird error while + * attempting to get the context classloader. + * + * @throws SecurityException if the current java security policy doesn't + * allow this class to access the context classloader. + */ + protected static ClassLoader getContextClassLoader() + throws LogConfigurationException { + + return (ClassLoader)AccessController.doPrivileged( + new PrivilegedAction() { + public Object run() { + return directGetContextClassLoader(); + } + }); + } + + /** + * Return the thread context class loader if available; otherwise return + * null. + * <p> + * Most/all code should call getContextClassLoader rather than calling + * this method directly. + * <p> + * The thread context class loader is available for JDK 1.2 + * or later, if certain security conditions are met. + * <p> + * Note that no internal logging is done within this method because + * this method is called every time LogFactory.getLogger() is called, + * and we don't want too much output generated here. + * + * @exception LogConfigurationException if a suitable class loader + * cannot be identified. + * + * @exception SecurityException if the java security policy forbids + * access to the context classloader from one of the classes in the + * current call stack. + * @since 1.1 + */ + protected static ClassLoader directGetContextClassLoader() + throws LogConfigurationException + { + ClassLoader classLoader = null; + + try { + // Are we running on a JDK 1.2 or later system? + Method method = Thread.class.getMethod("getContextClassLoader", + (Class[]) null); + + // Get the thread context class loader (if there is one) + try { + classLoader = (ClassLoader)method.invoke(Thread.currentThread(), + (Object[]) null); + } catch (IllegalAccessException e) { + throw new LogConfigurationException + ("Unexpected IllegalAccessException", e); + } catch (InvocationTargetException e) { + /** + * InvocationTargetException is thrown by 'invoke' when + * the method being invoked (getContextClassLoader) throws + * an exception. + * + * getContextClassLoader() throws SecurityException when + * the context class loader isn't an ancestor of the + * calling class's class loader, or if security + * permissions are restricted. + * + * In the first case (not related), we want to ignore and + * keep going. We cannot help but also ignore the second + * with the logic below, but other calls elsewhere (to + * obtain a class loader) will trigger this exception where + * we can make a distinction. + */ + if (e.getTargetException() instanceof SecurityException) { + ; // ignore + } else { + // Capture 'e.getTargetException()' exception for details + // alternate: log 'e.getTargetException()', and pass back 'e'. + throw new LogConfigurationException + ("Unexpected InvocationTargetException", e.getTargetException()); + } + } + } catch (NoSuchMethodException e) { + // Assume we are running on JDK 1.1 + classLoader = getClassLoader(LogFactory.class); + + // We deliberately don't log a message here to outputStream; + // this message would be output for every call to LogFactory.getLog() + // when running on JDK1.1 + // + // if (outputStream != null) { + // outputStream.println( + // "Method Thread.getContextClassLoader does not exist;" + // + " assuming this is JDK 1.1, and that the context" + // + " classloader is the same as the class that loaded" + // + " the concrete LogFactory class."); + // } + + } + + // Return the selected class loader + return classLoader; + } + + /** + * Check cached factories (keyed by contextClassLoader) + * + * @param contextClassLoader is the context classloader associated + * with the current thread. This allows separate LogFactory objects + * per component within a container, provided each component has + * a distinct context classloader set. This parameter may be null + * in JDK1.1, and in embedded systems where jcl-using code is + * placed in the bootclasspath. + * + * @return the factory associated with the specified classloader if + * one has previously been created, or null if this is the first time + * we have seen this particular classloader. + */ + private static LogFactory getCachedFactory(ClassLoader contextClassLoader) + { + LogFactory factory = null; + + if (contextClassLoader == null) { + // We have to handle this specially, as factories is a Hashtable + // and those don't accept null as a key value. + // + // nb: nullClassLoaderFactory might be null. That's ok. + factory = nullClassLoaderFactory; + } else { + factory = (LogFactory) factories.get(contextClassLoader); + } + + return factory; + } + + /** + * Remember this factory, so later calls to LogFactory.getCachedFactory + * can return the previously created object (together with all its + * cached Log objects). + * + * @param classLoader should be the current context classloader. Note that + * this can be null under some circumstances; this is ok. + * + * @param factory should be the factory to cache. This should never be null. + */ + private static void cacheFactory(ClassLoader classLoader, LogFactory factory) + { + // Ideally we would assert(factory != null) here. However reporting + // errors from within a logging implementation is a little tricky! + + if (factory != null) { + if (classLoader == null) { + nullClassLoaderFactory = factory; + } else { + factories.put(classLoader, factory); + } + } + } + + /** + * Return a new instance of the specified <code>LogFactory</code> + * implementation class, loaded by the specified class loader. + * If that fails, try the class loader used to load this + * (abstract) LogFactory. + * <p> + * <h2>ClassLoader conflicts</h2> + * Note that there can be problems if the specified ClassLoader is not the + * same as the classloader that loaded this class, ie when loading a + * concrete LogFactory subclass via a context classloader. + * <p> + * The problem is the same one that can occur when loading a concrete Log + * subclass via a context classloader. + * <p> + * The problem occurs when code running in the context classloader calls + * class X which was loaded via a parent classloader, and class X then calls + * LogFactory.getFactory (either directly or via LogFactory.getLog). Because + * class X was loaded via the parent, it binds to LogFactory loaded via + * the parent. When the code in this method finds some LogFactoryYYYY + * class in the child (context) classloader, and there also happens to be a + * LogFactory class defined in the child classloader, then LogFactoryYYYY + * will be bound to LogFactory@childloader. It cannot be cast to + * LogFactory@parentloader, ie this method cannot return the object as + * the desired type. Note that it doesn't matter if the LogFactory class + * in the child classloader is identical to the LogFactory class in the + * parent classloader, they are not compatible. + * <p> + * The solution taken here is to simply print out an error message when + * this occurs then throw an exception. The deployer of the application + * must ensure they remove all occurrences of the LogFactory class from + * the child classloader in order to resolve the issue. Note that they + * do not have to move the custom LogFactory subclass; that is ok as + * long as the only LogFactory class it can find to bind to is in the + * parent classloader. + * <p> + * @param factoryClass Fully qualified name of the <code>LogFactory</code> + * implementation class + * @param classLoader ClassLoader from which to load this class + * @param contextClassLoader is the context that this new factory will + * manage logging for. + * + * @exception LogConfigurationException if a suitable instance + * cannot be created + * @since 1.1 + */ + protected static LogFactory newFactory(final String factoryClass, + final ClassLoader classLoader, + final ClassLoader contextClassLoader) + throws LogConfigurationException + { + // Note that any unchecked exceptions thrown by the createFactory + // method will propagate out of this method; in particular a + // ClassCastException can be thrown. + Object result = AccessController.doPrivileged( + new PrivilegedAction() { + public Object run() { + return createFactory(factoryClass, classLoader); + } + }); + + if (result instanceof LogConfigurationException) { + LogConfigurationException ex = (LogConfigurationException) result; + if (isDiagnosticsEnabled()) { + logDiagnostic( + "An error occurred while loading the factory class:" + + ex.getMessage()); + } + throw ex; + } + if (isDiagnosticsEnabled()) { + logDiagnostic( + "Created object " + objectId(result) + + " to manage classloader " + objectId(contextClassLoader)); + } + return (LogFactory)result; + } + + /** + * Method provided for backwards compatibility; see newFactory version that + * takes 3 parameters. + * <p> + * This method would only ever be called in some rather odd situation. + * Note that this method is static, so overriding in a subclass doesn't + * have any effect unless this method is called from a method in that + * subclass. However this method only makes sense to use from the + * getFactory method, and as that is almost always invoked via + * LogFactory.getFactory, any custom definition in a subclass would be + * pointless. Only a class with a custom getFactory method, then invoked + * directly via CustomFactoryImpl.getFactory or similar would ever call + * this. Anyway, it's here just in case, though the "managed class loader" + * value output to the diagnostics will not report the correct value. + */ + protected static LogFactory newFactory(final String factoryClass, + final ClassLoader classLoader) { + return newFactory(factoryClass, classLoader, null); + } + + /** + * Implements the operations described in the javadoc for newFactory. + * + * @param factoryClass + * + * @param classLoader used to load the specified factory class. This is + * expected to be either the TCCL or the classloader which loaded this + * class. Note that the classloader which loaded this class might be + * "null" (ie the bootloader) for embedded systems. + * + * @return either a LogFactory object or a LogConfigurationException object. + * @since 1.1 + */ + protected static Object createFactory(String factoryClass, ClassLoader classLoader) { + + // This will be used to diagnose bad configurations + // and allow a useful message to be sent to the user + Class logFactoryClass = null; + try { + if (classLoader != null) { + try { + // First the given class loader param (thread class loader) + + // Warning: must typecast here & allow exception + // to be generated/caught & recast properly. + logFactoryClass = classLoader.loadClass(factoryClass); + if (LogFactory.class.isAssignableFrom(logFactoryClass)) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "Loaded class " + logFactoryClass.getName() + + " from classloader " + objectId(classLoader)); + } + } else { + // + // This indicates a problem with the ClassLoader tree. + // An incompatible ClassLoader was used to load the + // implementation. + // As the same classes + // must be available in multiple class loaders, + // it is very likely that multiple JCL jars are present. + // The most likely fix for this + // problem is to remove the extra JCL jars from the + // ClassLoader hierarchy. + // + if (isDiagnosticsEnabled()) { + logDiagnostic( + "Factory class " + logFactoryClass.getName() + + " loaded from classloader " + objectId(logFactoryClass.getClassLoader()) + + " does not extend '" + LogFactory.class.getName() + + "' as loaded by this classloader."); + logHierarchy("[BAD CL TREE] ", classLoader); + } + } + + return (LogFactory) logFactoryClass.newInstance(); + + } catch (ClassNotFoundException ex) { + if (classLoader == thisClassLoader) { + // Nothing more to try, onwards. + if (isDiagnosticsEnabled()) { + logDiagnostic( + "Unable to locate any class called '" + factoryClass + + "' via classloader " + objectId(classLoader)); + } + throw ex; + } + // ignore exception, continue + } catch (NoClassDefFoundError e) { + if (classLoader == thisClassLoader) { + // Nothing more to try, onwards. + if (isDiagnosticsEnabled()) { + logDiagnostic( + "Class '" + factoryClass + "' cannot be loaded" + + " via classloader " + objectId(classLoader) + + " - it depends on some other class that cannot" + + " be found."); + } + throw e; + } + // ignore exception, continue + } catch(ClassCastException e) { + if (classLoader == thisClassLoader) { + // There's no point in falling through to the code below that + // tries again with thisClassLoader, because we've just tried + // loading with that loader (not the TCCL). Just throw an + // appropriate exception here. + + final boolean implementsLogFactory = implementsLogFactory(logFactoryClass); + + // + // Construct a good message: users may not actual expect that a custom implementation + // has been specified. Several well known containers use this mechanism to adapt JCL + // to their native logging system. + // + String msg = + "The application has specified that a custom LogFactory implementation should be used but " + + "Class '" + factoryClass + "' cannot be converted to '" + + LogFactory.class.getName() + "'. "; + if (implementsLogFactory) { + msg = msg + "The conflict is caused by the presence of multiple LogFactory classes in incompatible classloaders. " + + "Background can be found in http://jakarta.apache.org/commons/logging/tech.html. " + + "If you have not explicitly specified a custom LogFactory then it is likely that " + + "the container has set one without your knowledge. " + + "In this case, consider using the commons-logging-adapters.jar file or " + + "specifying the standard LogFactory from the command line. "; + } else { + msg = msg + "Please check the custom implementation. "; + } + msg = msg + "Help can be found @http://jakarta.apache.org/commons/logging/troubleshooting.html."; + + if (isDiagnosticsEnabled()) { + logDiagnostic(msg); + } + + ClassCastException ex = new ClassCastException(msg); + throw ex; + } + + // Ignore exception, continue. Presumably the classloader was the + // TCCL; the code below will try to load the class via thisClassLoader. + // This will handle the case where the original calling class is in + // a shared classpath but the TCCL has a copy of LogFactory and the + // specified LogFactory implementation; we will fall back to using the + // LogFactory implementation from the same classloader as this class. + // + // Issue: this doesn't handle the reverse case, where this LogFactory + // is in the webapp, and the specified LogFactory implementation is + // in a shared classpath. In that case: + // (a) the class really does implement LogFactory (bad log msg above) + // (b) the fallback code will result in exactly the same problem. + } + } + + /* At this point, either classLoader == null, OR + * classLoader was unable to load factoryClass. + * + * In either case, we call Class.forName, which is equivalent + * to LogFactory.class.getClassLoader().load(name), ie we ignore + * the classloader parameter the caller passed, and fall back + * to trying the classloader associated with this class. See the + * javadoc for the newFactory method for more info on the + * consequences of this. + * + * Notes: + * * LogFactory.class.getClassLoader() may return 'null' + * if LogFactory is loaded by the bootstrap classloader. + */ + // Warning: must typecast here & allow exception + // to be generated/caught & recast properly. + if (isDiagnosticsEnabled()) { + logDiagnostic( + "Unable to load factory class via classloader " + + objectId(classLoader) + + " - trying the classloader associated with this LogFactory."); + } + logFactoryClass = Class.forName(factoryClass); + return (LogFactory) logFactoryClass.newInstance(); + } catch (Exception e) { + // Check to see if we've got a bad configuration + if (isDiagnosticsEnabled()) { + logDiagnostic("Unable to create LogFactory instance."); + } + if (logFactoryClass != null + && !LogFactory.class.isAssignableFrom(logFactoryClass)) { + + return new LogConfigurationException( + "The chosen LogFactory implementation does not extend LogFactory." + + " Please check your configuration.", + e); + } + return new LogConfigurationException(e); + } + } + + /** + * Determines whether the given class actually implements <code>LogFactory</code>. + * Diagnostic information is also logged. + * <p> + * <strong>Usage:</strong> to diagnose whether a classloader conflict is the cause + * of incompatibility. The test used is whether the class is assignable from + * the <code>LogFactory</code> class loaded by the class's classloader. + * @param logFactoryClass <code>Class</code> which may implement <code>LogFactory</code> + * @return true if the <code>logFactoryClass</code> does extend + * <code>LogFactory</code> when that class is loaded via the same + * classloader that loaded the <code>logFactoryClass</code>. + */ + private static boolean implementsLogFactory(Class logFactoryClass) { + boolean implementsLogFactory = false; + if (logFactoryClass != null) { + try { + ClassLoader logFactoryClassLoader = logFactoryClass.getClassLoader(); + if (logFactoryClassLoader == null) { + logDiagnostic("[CUSTOM LOG FACTORY] was loaded by the boot classloader"); + } else { + logHierarchy("[CUSTOM LOG FACTORY] ", logFactoryClassLoader); + Class factoryFromCustomLoader + = Class.forName("org.apache.commons.logging.LogFactory", false, logFactoryClassLoader); + implementsLogFactory = factoryFromCustomLoader.isAssignableFrom(logFactoryClass); + if (implementsLogFactory) { + logDiagnostic("[CUSTOM LOG FACTORY] " + logFactoryClass.getName() + + " implements LogFactory but was loaded by an incompatible classloader."); + } else { + logDiagnostic("[CUSTOM LOG FACTORY] " + logFactoryClass.getName() + + " does not implement LogFactory."); + } + } + } catch (SecurityException e) { + // + // The application is running within a hostile security environment. + // This will make it very hard to diagnose issues with JCL. + // Consider running less securely whilst debugging this issue. + // + logDiagnostic("[CUSTOM LOG FACTORY] SecurityException thrown whilst trying to determine whether " + + "the compatibility was caused by a classloader conflict: " + + e.getMessage()); + } catch (LinkageError e) { + // + // This should be an unusual circumstance. + // LinkageError's usually indicate that a dependent class has incompatibly changed. + // Another possibility may be an exception thrown by an initializer. + // Time for a clean rebuild? + // + logDiagnostic("[CUSTOM LOG FACTORY] LinkageError thrown whilst trying to determine whether " + + "the compatibility was caused by a classloader conflict: " + + e.getMessage()); + } catch (ClassNotFoundException e) { + // + // LogFactory cannot be loaded by the classloader which loaded the custom factory implementation. + // The custom implementation is not viable until this is corrected. + // Ensure that the JCL jar and the custom class are available from the same classloader. + // Running with diagnostics on should give information about the classloaders used + // to load the custom factory. + // + logDiagnostic("[CUSTOM LOG FACTORY] LogFactory class cannot be loaded by classloader which loaded the " + + "custom LogFactory implementation. Is the custom factory in the right classloader?"); + } + } + return implementsLogFactory; + } + + /** + * Applets may run in an environment where accessing resources of a loader is + * a secure operation, but where the commons-logging library has explicitly + * been granted permission for that operation. In this case, we need to + * run the operation using an AccessController. + */ + private static InputStream getResourceAsStream(final ClassLoader loader, + final String name) + { + return (InputStream)AccessController.doPrivileged( + new PrivilegedAction() { + public Object run() { + if (loader != null) { + return loader.getResourceAsStream(name); + } else { + return ClassLoader.getSystemResourceAsStream(name); + } + } + }); + } + + /** + * Given a filename, return an enumeration of URLs pointing to + * all the occurrences of that filename in the classpath. + * <p> + * This is just like ClassLoader.getResources except that the + * operation is done under an AccessController so that this method will + * succeed when this jarfile is privileged but the caller is not. + * This method must therefore remain private to avoid security issues. + * <p> + * If no instances are found, an Enumeration is returned whose + * hasMoreElements method returns false (ie an "empty" enumeration). + * If resources could not be listed for some reason, null is returned. + */ + private static Enumeration getResources(final ClassLoader loader, + final String name) + { + PrivilegedAction action = + new PrivilegedAction() { + public Object run() { + try { + if (loader != null) { + return loader.getResources(name); + } else { + return ClassLoader.getSystemResources(name); + } + } catch(IOException e) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "Exception while trying to find configuration file " + + name + ":" + e.getMessage()); + } + return null; + } catch(NoSuchMethodError e) { + // we must be running on a 1.1 JVM which doesn't support + // ClassLoader.getSystemResources; just return null in + // this case. + return null; + } + } + }; + Object result = AccessController.doPrivileged(action); + return (Enumeration) result; + } + + /** + * Given a URL that refers to a .properties file, load that file. + * This is done under an AccessController so that this method will + * succeed when this jarfile is privileged but the caller is not. + * This method must therefore remain private to avoid security issues. + * <p> + * Null is returned if the URL cannot be opened. + */ + private static Properties getProperties(final URL url) { + PrivilegedAction action = + new PrivilegedAction() { + public Object run() { + try { + InputStream stream = url.openStream(); + if (stream != null) { + Properties props = new Properties(); + props.load(stream); + stream.close(); + return props; + } + } catch(IOException e) { + if (isDiagnosticsEnabled()) { + logDiagnostic("Unable to read URL " + url); + } + } + + return null; + } + }; + return (Properties) AccessController.doPrivileged(action); + } + + /** + * Locate a user-provided configuration file. + * <p> + * The classpath of the specified classLoader (usually the context classloader) + * is searched for properties files of the specified name. If none is found, + * null is returned. If more than one is found, then the file with the greatest + * value for its PRIORITY property is returned. If multiple files have the + * same PRIORITY value then the first in the classpath is returned. + * <p> + * This differs from the 1.0.x releases; those always use the first one found. + * However as the priority is a new field, this change is backwards compatible. + * <p> + * The purpose of the priority field is to allow a webserver administrator to + * override logging settings in all webapps by placing a commons-logging.properties + * file in a shared classpath location with a priority > 0; this overrides any + * commons-logging.properties files without priorities which are in the + * webapps. Webapps can also use explicit priorities to override a configuration + * file in the shared classpath if needed. + */ + private static final Properties getConfigurationFile( + ClassLoader classLoader, String fileName) { + + Properties props = null; + double priority = 0.0; + URL propsUrl = null; + try { + Enumeration urls = getResources(classLoader, fileName); + + if (urls == null) { + return null; + } + + while (urls.hasMoreElements()) { + URL url = (URL) urls.nextElement(); + + Properties newProps = getProperties(url); + if (newProps != null) { + if (props == null) { + propsUrl = url; + props = newProps; + String priorityStr = props.getProperty(PRIORITY_KEY); + priority = 0.0; + if (priorityStr != null) { + priority = Double.parseDouble(priorityStr); + } + + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] Properties file found at '" + url + "'" + + " with priority " + priority); + } + } else { + String newPriorityStr = newProps.getProperty(PRIORITY_KEY); + double newPriority = 0.0; + if (newPriorityStr != null) { + newPriority = Double.parseDouble(newPriorityStr); + } + + if (newPriority > priority) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] Properties file at '" + url + "'" + + " with priority " + newPriority + + " overrides file at '" + propsUrl + "'" + + " with priority " + priority); + } + + propsUrl = url; + props = newProps; + priority = newPriority; + } else { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[LOOKUP] Properties file at '" + url + "'" + + " with priority " + newPriority + + " does not override file at '" + propsUrl + "'" + + " with priority " + priority); + } + } + } + + } + } + } catch (SecurityException e) { + if (isDiagnosticsEnabled()) { + logDiagnostic("SecurityException thrown while trying to find/read config files."); + } + } + + if (isDiagnosticsEnabled()) { + if (props == null) { + logDiagnostic( + "[LOOKUP] No properties file of name '" + fileName + + "' found."); + } else { + logDiagnostic( + "[LOOKUP] Properties file of name '" + fileName + + "' found at '" + propsUrl + '"'); + } + } + + return props; + } + + /** + * Determines whether the user wants internal diagnostic output. If so, + * returns an appropriate writer object. Users can enable diagnostic + * output by setting the system property named {@link #DIAGNOSTICS_DEST_PROPERTY} to + * a filename, or the special values STDOUT or STDERR. + */ + private static void initDiagnostics() { + String dest; + try { + dest = System.getProperty(DIAGNOSTICS_DEST_PROPERTY); + if (dest == null) { + return; + } + } catch(SecurityException ex) { + // We must be running in some very secure environment. + // We just have to assume output is not wanted.. + return; + } + + if (dest.equals("STDOUT")) { + diagnosticsStream = System.out; + } else if (dest.equals("STDERR")) { + diagnosticsStream = System.err; + } else { + try { + // open the file in append mode + FileOutputStream fos = new FileOutputStream(dest, true); + diagnosticsStream = new PrintStream(fos); + } catch(IOException ex) { + // We should report this to the user - but how? + return; + } + } + + // In order to avoid confusion where multiple instances of JCL are + // being used via different classloaders within the same app, we + // ensure each logged message has a prefix of form + // [LogFactory from classloader OID] + // + // Note that this prefix should be kept consistent with that + // in LogFactoryImpl. However here we don't need to output info + // about the actual *instance* of LogFactory, as all methods that + // output diagnostics from this class are static. + String classLoaderName; + try { + ClassLoader classLoader = thisClassLoader; + if (thisClassLoader == null) { + classLoaderName = "BOOTLOADER"; + } else { + classLoaderName = objectId(classLoader); + } + } catch(SecurityException e) { + classLoaderName = "UNKNOWN"; + } + diagnosticPrefix = "[LogFactory from " + classLoaderName + "] "; + } + + /** + * Indicates true if the user has enabled internal logging. + * <p> + * By the way, sorry for the incorrect grammar, but calling this method + * areDiagnosticsEnabled just isn't java beans style. + * + * @return true if calls to logDiagnostic will have any effect. + * @since 1.1 + */ + protected static boolean isDiagnosticsEnabled() { + return diagnosticsStream != null; + } + + /** + * Write the specified message to the internal logging destination. + * <p> + * Note that this method is private; concrete subclasses of this class + * should not call it because the diagnosticPrefix string this + * method puts in front of all its messages is LogFactory@...., + * while subclasses should put SomeSubClass@... + * <p> + * Subclasses should instead compute their own prefix, then call + * logRawDiagnostic. Note that calling isDiagnosticsEnabled is + * fine for subclasses. + * <p> + * Note that it is safe to call this method before initDiagnostics + * is called; any output will just be ignored (as isDiagnosticsEnabled + * will return false). + * + * @param msg is the diagnostic message to be output. + */ + private static final void logDiagnostic(String msg) { + if (diagnosticsStream != null) { + diagnosticsStream.print(diagnosticPrefix); + diagnosticsStream.println(msg); + diagnosticsStream.flush(); + } + } + + /** + * Write the specified message to the internal logging destination. + * + * @param msg is the diagnostic message to be output. + * @since 1.1 + */ + protected static final void logRawDiagnostic(String msg) { + if (diagnosticsStream != null) { + diagnosticsStream.println(msg); + diagnosticsStream.flush(); + } + } + + /** + * Generate useful diagnostics regarding the classloader tree for + * the specified class. + * <p> + * As an example, if the specified class was loaded via a webapp's + * classloader, then you may get the following output: + * <pre> + * Class com.acme.Foo was loaded via classloader 11111 + * ClassLoader tree: 11111 -> 22222 (SYSTEM) -> 33333 -> BOOT + * </pre> + * <p> + * This method returns immediately if isDiagnosticsEnabled() + * returns false. + * + * @param clazz is the class whose classloader + tree are to be + * output. + */ + private static void logClassLoaderEnvironment(Class clazz) { + if (!isDiagnosticsEnabled()) { + return; + } + + try { + logDiagnostic("[ENV] Extension directories (java.ext.dir): " + System.getProperty("java.ext.dir")); + logDiagnostic("[ENV] Application classpath (java.class.path): " + System.getProperty("java.class.path")); + } catch(SecurityException ex) { + logDiagnostic("[ENV] Security setting prevent interrogation of system classpaths."); + } + + String className = clazz.getName(); + ClassLoader classLoader; + + try { + classLoader = getClassLoader(clazz); + } catch(SecurityException ex) { + // not much useful diagnostics we can print here! + logDiagnostic( + "[ENV] Security forbids determining the classloader for " + className); + return; + } + + logDiagnostic( + "[ENV] Class " + className + " was loaded via classloader " + + objectId(classLoader)); + logHierarchy("[ENV] Ancestry of classloader which loaded " + className + " is ", classLoader); + } + + /** + * Logs diagnostic messages about the given classloader + * and it's hierarchy. The prefix is prepended to the message + * and is intended to make it easier to understand the logs. + * @param prefix + * @param classLoader + */ + private static void logHierarchy(String prefix, ClassLoader classLoader) { + if (!isDiagnosticsEnabled()) { + return; + } + ClassLoader systemClassLoader; + if (classLoader != null) { + final String classLoaderString = classLoader.toString(); + logDiagnostic(prefix + objectId(classLoader) + " == '" + classLoaderString + "'"); + } + + try { + systemClassLoader = ClassLoader.getSystemClassLoader(); + } catch(SecurityException ex) { + logDiagnostic( + prefix + "Security forbids determining the system classloader."); + return; + } + if (classLoader != null) { + StringBuffer buf = new StringBuffer(prefix + "ClassLoader tree:"); + for(;;) { + buf.append(objectId(classLoader)); + if (classLoader == systemClassLoader) { + buf.append(" (SYSTEM) "); + } + + try { + classLoader = classLoader.getParent(); + } catch(SecurityException ex) { + buf.append(" --> SECRET"); + break; + } + + buf.append(" --> "); + if (classLoader == null) { + buf.append("BOOT"); + break; + } + } + logDiagnostic(buf.toString()); + } + } + + /** + * Returns a string that uniquely identifies the specified object, including + * its class. + * <p> + * The returned string is of form "classname@hashcode", ie is the same as + * the return value of the Object.toString() method, but works even when + * the specified object's class has overidden the toString method. + * + * @param o may be null. + * @return a string of form classname@hashcode, or "null" if param o is null. + * @since 1.1 + */ + public static String objectId(Object o) { + if (o == null) { + return "null"; + } else { + return o.getClass().getName() + "@" + System.identityHashCode(o); + } + } + + // ---------------------------------------------------------------------- + // Static initialiser block to perform initialisation at class load time. + // + // We can't do this in the class constructor, as there are many + // static methods on this class that can be called before any + // LogFactory instances are created, and they depend upon this + // stuff having been set up. + // + // Note that this block must come after any variable declarations used + // by any methods called from this block, as we want any static initialiser + // associated with the variable to run first. If static initialisers for + // variables run after this code, then (a) their value might be needed + // by methods called from here, and (b) they might *override* any value + // computed here! + // + // So the wisest thing to do is just to place this code at the very end + // of the class file. + // ---------------------------------------------------------------------- + + static { + // note: it's safe to call methods before initDiagnostics. + thisClassLoader = getClassLoader(LogFactory.class); + initDiagnostics(); + logClassLoaderEnvironment(LogFactory.class); + factories = createFactoryStore(); + if (isDiagnosticsEnabled()) { + logDiagnostic("BOOTSTRAP COMPLETED"); + } + } +} diff --git a/src/org/apache/commons/logging/LogSource.java b/src/org/apache/commons/logging/LogSource.java new file mode 100644 index 0000000..e3c0603 --- /dev/null +++ b/src/org/apache/commons/logging/LogSource.java @@ -0,0 +1,261 @@ +/* + * Copyright 2001-2004 The Apache Software Foundation. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.commons.logging; + + +import java.lang.reflect.Constructor; +import java.util.Hashtable; + +import org.apache.commons.logging.impl.NoOpLog; + + +/** + * <p>Factory for creating {@link Log} instances. Applications should call + * the <code>makeNewLogInstance()</code> method to instantiate new instances + * of the configured {@link Log} implementation class.</p> + * + * <p>By default, calling <code>getInstance()</code> will use the following + * algorithm:</p> + * <ul> + * <li>If Log4J is available, return an instance of + * <code>org.apache.commons.logging.impl.Log4JLogger</code>.</li> + * <li>If JDK 1.4 or later is available, return an instance of + * <code>org.apache.commons.logging.impl.Jdk14Logger</code>.</li> + * <li>Otherwise, return an instance of + * <code>org.apache.commons.logging.impl.NoOpLog</code>.</li> + * </ul> + * + * <p>You can change the default behavior in one of two ways:</p> + * <ul> + * <li>On the startup command line, set the system property + * <code>org.apache.commons.logging.log</code> to the name of the + * <code>org.apache.commons.logging.Log</code> implementation class + * you want to use.</li> + * <li>At runtime, call <code>LogSource.setLogImplementation()</code>.</li> + * </ul> + * + * @deprecated Use {@link LogFactory} instead - The default factory + * implementation performs exactly the same algorithm as this class did + * + * @author Rod Waldhoff + * @version $Id: LogSource.java 155426 2005-02-26 13:10:49Z dirkv $ + */ +public class LogSource { + + // ------------------------------------------------------- Class Attributes + + static protected Hashtable logs = new Hashtable(); + + /** Is log4j available (in the current classpath) */ + static protected boolean log4jIsAvailable = false; + + /** Is JDK 1.4 logging available */ + static protected boolean jdk14IsAvailable = false; + + /** Constructor for current log class */ + static protected Constructor logImplctor = null; + + + // ----------------------------------------------------- Class Initializers + + static { + + // Is Log4J Available? + try { + if (null != Class.forName("org.apache.log4j.Logger")) { + log4jIsAvailable = true; + } else { + log4jIsAvailable = false; + } + } catch (Throwable t) { + log4jIsAvailable = false; + } + + // Is JDK 1.4 Logging Available? + try { + if ((null != Class.forName("java.util.logging.Logger")) && + (null != Class.forName("org.apache.commons.logging.impl.Jdk14Logger"))) { + jdk14IsAvailable = true; + } else { + jdk14IsAvailable = false; + } + } catch (Throwable t) { + jdk14IsAvailable = false; + } + + // Set the default Log implementation + String name = null; + try { + name = System.getProperty("org.apache.commons.logging.log"); + if (name == null) { + name = System.getProperty("org.apache.commons.logging.Log"); + } + } catch (Throwable t) { + } + if (name != null) { + try { + setLogImplementation(name); + } catch (Throwable t) { + try { + setLogImplementation + ("org.apache.commons.logging.impl.NoOpLog"); + } catch (Throwable u) { + ; + } + } + } else { + try { + if (log4jIsAvailable) { + setLogImplementation + ("org.apache.commons.logging.impl.Log4JLogger"); + } else if (jdk14IsAvailable) { + setLogImplementation + ("org.apache.commons.logging.impl.Jdk14Logger"); + } else { + setLogImplementation + ("org.apache.commons.logging.impl.NoOpLog"); + } + } catch (Throwable t) { + try { + setLogImplementation + ("org.apache.commons.logging.impl.NoOpLog"); + } catch (Throwable u) { + ; + } + } + } + + } + + + // ------------------------------------------------------------ Constructor + + + /** Don't allow others to create instances */ + private LogSource() { + } + + + // ---------------------------------------------------------- Class Methods + + + /** + * Set the log implementation/log implementation factory + * by the name of the class. The given class + * must implement {@link Log}, and provide a constructor that + * takes a single {@link String} argument (containing the name + * of the log). + */ + static public void setLogImplementation(String classname) throws + LinkageError, ExceptionInInitializerError, + NoSuchMethodException, SecurityException, + ClassNotFoundException { + try { + Class logclass = Class.forName(classname); + Class[] argtypes = new Class[1]; + argtypes[0] = "".getClass(); + logImplctor = logclass.getConstructor(argtypes); + } catch (Throwable t) { + logImplctor = null; + } + } + + + /** + * Set the log implementation/log implementation factory + * by class. The given class must implement {@link Log}, + * and provide a constructor that takes a single {@link String} + * argument (containing the name of the log). + */ + static public void setLogImplementation(Class logclass) throws + LinkageError, ExceptionInInitializerError, + NoSuchMethodException, SecurityException { + Class[] argtypes = new Class[1]; + argtypes[0] = "".getClass(); + logImplctor = logclass.getConstructor(argtypes); + } + + + /** Get a <code>Log</code> instance by class name */ + static public Log getInstance(String name) { + Log log = (Log) (logs.get(name)); + if (null == log) { + log = makeNewLogInstance(name); + logs.put(name, log); + } + return log; + } + + + /** Get a <code>Log</code> instance by class */ + static public Log getInstance(Class clazz) { + return getInstance(clazz.getName()); + } + + + /** + * Create a new {@link Log} implementation, based + * on the given <i>name</i>. + * <p> + * The specific {@link Log} implementation returned + * is determined by the value of the + * <tt>org.apache.commons.logging.log</tt> property. + * The value of <tt>org.apache.commons.logging.log</tt> may be set to + * the fully specified name of a class that implements + * the {@link Log} interface. This class must also + * have a public constructor that takes a single + * {@link String} argument (containing the <i>name</i> + * of the {@link Log} to be constructed. + * <p> + * When <tt>org.apache.commons.logging.log</tt> is not set, + * or when no corresponding class can be found, + * this method will return a Log4JLogger + * if the log4j Logger class is + * available in the {@link LogSource}'s classpath, or a + * Jdk14Logger if we are on a JDK 1.4 or later system, or + * NoOpLog if neither of the above conditions is true. + * + * @param name the log name (or category) + */ + static public Log makeNewLogInstance(String name) { + + Log log = null; + try { + Object[] args = new Object[1]; + args[0] = name; + log = (Log) (logImplctor.newInstance(args)); + } catch (Throwable t) { + log = null; + } + if (null == log) { + log = new NoOpLog(name); + } + return log; + + } + + + /** + * Returns a {@link String} array containing the names of + * all logs known to me. + */ + static public String[] getLogNames() { + return (String[]) (logs.keySet().toArray(new String[logs.size()])); + } + + +} diff --git a/src/org/apache/commons/logging/impl/Jdk14Logger.java b/src/org/apache/commons/logging/impl/Jdk14Logger.java new file mode 100644 index 0000000..d4f840c --- /dev/null +++ b/src/org/apache/commons/logging/impl/Jdk14Logger.java @@ -0,0 +1,303 @@ +/* + * Copyright 2001-2004 The Apache Software Foundation. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + + +package org.apache.commons.logging.impl; + + +import java.io.Serializable; +import java.util.logging.Level; +import java.util.logging.Logger; + +import org.apache.commons.logging.Log; + + +/** + * <p>Implementation of the <code>org.apache.commons.logging.Log</code> + * interface that wraps the standard JDK logging mechanisms that were + * introduced in the Merlin release (JDK 1.4).</p> + * + * @author <a href="mailto:sanders@apache.org">Scott Sanders</a> + * @author <a href="mailto:bloritsch@apache.org">Berin Loritsch</a> + * @author <a href="mailto:donaldp@apache.org">Peter Donald</a> + * @version $Revision: 370652 $ $Date: 2006-01-19 22:23:48 +0000 (Thu, 19 Jan 2006) $ + */ + +public class Jdk14Logger implements Log, Serializable { + + /** + * This member variable simply ensures that any attempt to initialise + * this class in a pre-1.4 JVM will result in an ExceptionInInitializerError. + * It must not be private, as an optimising compiler could detect that it + * is not used and optimise it away. + */ + protected static final Level dummyLevel = Level.FINE; + + // ----------------------------------------------------------- Constructors + + + /** + * Construct a named instance of this Logger. + * + * @param name Name of the logger to be constructed + */ + public Jdk14Logger(String name) { + + this.name = name; + logger = getLogger(); + + } + + + // ----------------------------------------------------- Instance Variables + + + /** + * The underlying Logger implementation we are using. + */ + protected transient Logger logger = null; + + + /** + * The name of the logger we are wrapping. + */ + protected String name = null; + + + // --------------------------------------------------------- Public Methods + + private void log( Level level, String msg, Throwable ex ) { + + Logger logger = getLogger(); + if (logger.isLoggable(level)) { + // Hack (?) to get the stack trace. + Throwable dummyException=new Throwable(); + StackTraceElement locations[]=dummyException.getStackTrace(); + // Caller will be the third element + String cname="unknown"; + String method="unknown"; + if( locations!=null && locations.length >2 ) { + StackTraceElement caller=locations[2]; + cname=caller.getClassName(); + method=caller.getMethodName(); + } + if( ex==null ) { + logger.logp( level, cname, method, msg ); + } else { + logger.logp( level, cname, method, msg, ex ); + } + } + + } + + /** + * Logs a message with <code>java.util.logging.Level.FINE</code>. + * + * @param message to log + * @see org.apache.commons.logging.Log#debug(Object) + */ + public void debug(Object message) { + log(Level.FINE, String.valueOf(message), null); + } + + + /** + * Logs a message with <code>java.util.logging.Level.FINE</code>. + * + * @param message to log + * @param exception log this cause + * @see org.apache.commons.logging.Log#debug(Object, Throwable) + */ + public void debug(Object message, Throwable exception) { + log(Level.FINE, String.valueOf(message), exception); + } + + + /** + * Logs a message with <code>java.util.logging.Level.SEVERE</code>. + * + * @param message to log + * @see org.apache.commons.logging.Log#error(Object) + */ + public void error(Object message) { + log(Level.SEVERE, String.valueOf(message), null); + } + + + /** + * Logs a message with <code>java.util.logging.Level.SEVERE</code>. + * + * @param message to log + * @param exception log this cause + * @see org.apache.commons.logging.Log#error(Object, Throwable) + */ + public void error(Object message, Throwable exception) { + log(Level.SEVERE, String.valueOf(message), exception); + } + + + /** + * Logs a message with <code>java.util.logging.Level.SEVERE</code>. + * + * @param message to log + * @see org.apache.commons.logging.Log#fatal(Object) + */ + public void fatal(Object message) { + log(Level.SEVERE, String.valueOf(message), null); + } + + + /** + * Logs a message with <code>java.util.logging.Level.SEVERE</code>. + * + * @param message to log + * @param exception log this cause + * @see org.apache.commons.logging.Log#fatal(Object, Throwable) + */ + public void fatal(Object message, Throwable exception) { + log(Level.SEVERE, String.valueOf(message), exception); + } + + + /** + * Return the native Logger instance we are using. + */ + public Logger getLogger() { + if (logger == null) { + logger = Logger.getLogger(name); + } + return (logger); + } + + + /** + * Logs a message with <code>java.util.logging.Level.INFO</code>. + * + * @param message to log + * @see org.apache.commons.logging.Log#info(Object) + */ + public void info(Object message) { + log(Level.INFO, String.valueOf(message), null); + } + + + /** + * Logs a message with <code>java.util.logging.Level.INFO</code>. + * + * @param message to log + * @param exception log this cause + * @see org.apache.commons.logging.Log#info(Object, Throwable) + */ + public void info(Object message, Throwable exception) { + log(Level.INFO, String.valueOf(message), exception); + } + + + /** + * Is debug logging currently enabled? + */ + public boolean isDebugEnabled() { + return (getLogger().isLoggable(Level.FINE)); + } + + + /** + * Is error logging currently enabled? + */ + public boolean isErrorEnabled() { + return (getLogger().isLoggable(Level.SEVERE)); + } + + + /** + * Is fatal logging currently enabled? + */ + public boolean isFatalEnabled() { + return (getLogger().isLoggable(Level.SEVERE)); + } + + + /** + * Is info logging currently enabled? + */ + public boolean isInfoEnabled() { + return (getLogger().isLoggable(Level.INFO)); + } + + + /** + * Is trace logging currently enabled? + */ + public boolean isTraceEnabled() { + return (getLogger().isLoggable(Level.FINEST)); + } + + + /** + * Is warn logging currently enabled? + */ + public boolean isWarnEnabled() { + return (getLogger().isLoggable(Level.WARNING)); + } + + + /** + * Logs a message with <code>java.util.logging.Level.FINEST</code>. + * + * @param message to log + * @see org.apache.commons.logging.Log#trace(Object) + */ + public void trace(Object message) { + log(Level.FINEST, String.valueOf(message), null); + } + + + /** + * Logs a message with <code>java.util.logging.Level.FINEST</code>. + * + * @param message to log + * @param exception log this cause + * @see org.apache.commons.logging.Log#trace(Object, Throwable) + */ + public void trace(Object message, Throwable exception) { + log(Level.FINEST, String.valueOf(message), exception); + } + + + /** + * Logs a message with <code>java.util.logging.Level.WARNING</code>. + * + * @param message to log + * @see org.apache.commons.logging.Log#warn(Object) + */ + public void warn(Object message) { + log(Level.WARNING, String.valueOf(message), null); + } + + + /** + * Logs a message with <code>java.util.logging.Level.WARNING</code>. + * + * @param message to log + * @param exception log this cause + * @see org.apache.commons.logging.Log#warn(Object, Throwable) + */ + public void warn(Object message, Throwable exception) { + log(Level.WARNING, String.valueOf(message), exception); + } + + +} diff --git a/src/org/apache/commons/logging/impl/LogFactoryImpl.java b/src/org/apache/commons/logging/impl/LogFactoryImpl.java new file mode 100644 index 0000000..8937b2f --- /dev/null +++ b/src/org/apache/commons/logging/impl/LogFactoryImpl.java @@ -0,0 +1,1400 @@ +/* + * Copyright 2001-2004 The Apache Software Foundation. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.commons.logging.impl; + + +import java.lang.reflect.Constructor; +import java.lang.reflect.InvocationTargetException; +import java.lang.reflect.Method; +import java.net.URL; +import java.util.Enumeration; +import java.util.Hashtable; +import java.util.Vector; + +import org.apache.commons.logging.Log; +import org.apache.commons.logging.LogConfigurationException; +import org.apache.commons.logging.LogFactory; + + +/** + * <p>Concrete subclass of {@link LogFactory} that implements the + * following algorithm to dynamically select a logging implementation + * class to instantiate a wrapper for.</p> + * <ul> + * <li>Use a factory configuration attribute named + * <code>org.apache.commons.logging.Log</code> to identify the + * requested implementation class.</li> + * <li>Use the <code>org.apache.commons.logging.Log</code> system property + * to identify the requested implementation class.</li> + * <li>If <em>Log4J</em> is available, return an instance of + * <code>org.apache.commons.logging.impl.Log4JLogger</code>.</li> + * <li>If <em>JDK 1.4 or later</em> is available, return an instance of + * <code>org.apache.commons.logging.impl.Jdk14Logger</code>.</li> + * <li>Otherwise, return an instance of + * <code>org.apache.commons.logging.impl.SimpleLog</code>.</li> + * </ul> + * + * <p>If the selected {@link Log} implementation class has a + * <code>setLogFactory()</code> method that accepts a {@link LogFactory} + * parameter, this method will be called on each newly created instance + * to identify the associated factory. This makes factory configuration + * attributes available to the Log instance, if it so desires.</p> + * + * <p>This factory will remember previously created <code>Log</code> instances + * for the same name, and will return them on repeated requests to the + * <code>getInstance()</code> method.</p> + * + * @author Rod Waldhoff + * @author Craig R. McClanahan + * @author Richard A. Sitze + * @author Brian Stansberry + * @version $Revision: 399224 $ $Date: 2006-05-03 10:25:54 +0100 (Wed, 03 May 2006) $ + */ + +public class LogFactoryImpl extends LogFactory { + + + /** Log4JLogger class name */ + private static final String LOGGING_IMPL_LOG4J_LOGGER = "org.apache.commons.logging.impl.Log4JLogger"; + /** Jdk14Logger class name */ + private static final String LOGGING_IMPL_JDK14_LOGGER = "org.apache.commons.logging.impl.Jdk14Logger"; + /** Jdk13LumberjackLogger class name */ + private static final String LOGGING_IMPL_LUMBERJACK_LOGGER = "org.apache.commons.logging.impl.Jdk13LumberjackLogger"; + /** SimpleLog class name */ + private static final String LOGGING_IMPL_SIMPLE_LOGGER = "org.apache.commons.logging.impl.SimpleLog"; + + private static final String PKG_IMPL="org.apache.commons.logging.impl."; + private static final int PKG_LEN = PKG_IMPL.length(); + + // ----------------------------------------------------------- Constructors + + + + /** + * Public no-arguments constructor required by the lookup mechanism. + */ + public LogFactoryImpl() { + super(); + initDiagnostics(); // method on this object + if (isDiagnosticsEnabled()) { + logDiagnostic("Instance created."); + } + } + + + // ----------------------------------------------------- Manifest Constants + + + /** + * The name (<code>org.apache.commons.logging.Log</code>) of the system + * property identifying our {@link Log} implementation class. + */ + public static final String LOG_PROPERTY = + "org.apache.commons.logging.Log"; + + + /** + * The deprecated system property used for backwards compatibility with + * old versions of JCL. + */ + protected static final String LOG_PROPERTY_OLD = + "org.apache.commons.logging.log"; + + /** + * The name (<code>org.apache.commons.logging.Log.allowFlawedContext</code>) + * of the system property which can be set true/false to + * determine system behaviour when a bad context-classloader is encountered. + * When set to false, a LogConfigurationException is thrown if + * LogFactoryImpl is loaded via a child classloader of the TCCL (this + * should never happen in sane systems). + * + * Default behaviour: true (tolerates bad context classloaders) + * + * See also method setAttribute. + */ + public static final String ALLOW_FLAWED_CONTEXT_PROPERTY = + "org.apache.commons.logging.Log.allowFlawedContext"; + + /** + * The name (<code>org.apache.commons.logging.Log.allowFlawedDiscovery</code>) + * of the system property which can be set true/false to + * determine system behaviour when a bad logging adapter class is + * encountered during logging discovery. When set to false, an + * exception will be thrown and the app will fail to start. When set + * to true, discovery will continue (though the user might end up + * with a different logging implementation than they expected). + * + * Default behaviour: true (tolerates bad logging adapters) + * + * See also method setAttribute. + */ + public static final String ALLOW_FLAWED_DISCOVERY_PROPERTY = + "org.apache.commons.logging.Log.allowFlawedDiscovery"; + + /** + * The name (<code>org.apache.commons.logging.Log.allowFlawedHierarchy</code>) + * of the system property which can be set true/false to + * determine system behaviour when a logging adapter class is + * encountered which has bound to the wrong Log class implementation. + * When set to false, an exception will be thrown and the app will fail + * to start. When set to true, discovery will continue (though the user + * might end up with a different logging implementation than they expected). + * + * Default behaviour: true (tolerates bad Log class hierarchy) + * + * See also method setAttribute. + */ + public static final String ALLOW_FLAWED_HIERARCHY_PROPERTY = + "org.apache.commons.logging.Log.allowFlawedHierarchy"; + + + /** + * The names of classes that will be tried (in order) as logging + * adapters. Each class is expected to implement the Log interface, + * and to throw NoClassDefFound or ExceptionInInitializerError when + * loaded if the underlying logging library is not available. Any + * other error indicates that the underlying logging library is available + * but broken/unusable for some reason. + */ + private static final String[] classesToDiscover = { + LOGGING_IMPL_LOG4J_LOGGER, + "org.apache.commons.logging.impl.Jdk14Logger", + "org.apache.commons.logging.impl.Jdk13LumberjackLogger", + "org.apache.commons.logging.impl.SimpleLog" + }; + + + // ----------------------------------------------------- Instance Variables + + /** + * Determines whether logging classes should be loaded using the thread-context + * classloader, or via the classloader that loaded this LogFactoryImpl class. + */ + private boolean useTCCL = true; + + /** + * The string prefixed to every message output by the logDiagnostic method. + */ + private String diagnosticPrefix; + + + /** + * Configuration attributes. + */ + protected Hashtable attributes = new Hashtable(); + + + /** + * The {@link org.apache.commons.logging.Log} instances that have + * already been created, keyed by logger name. + */ + protected Hashtable instances = new Hashtable(); + + + /** + * Name of the class implementing the Log interface. + */ + private String logClassName; + + + /** + * The one-argument constructor of the + * {@link org.apache.commons.logging.Log} + * implementation class that will be used to create new instances. + * This value is initialized by <code>getLogConstructor()</code>, + * and then returned repeatedly. + */ + protected Constructor logConstructor = null; + + + /** + * The signature of the Constructor to be used. + */ + protected Class logConstructorSignature[] = + { java.lang.String.class }; + + + /** + * The one-argument <code>setLogFactory</code> method of the selected + * {@link org.apache.commons.logging.Log} method, if it exists. + */ + protected Method logMethod = null; + + + /** + * The signature of the <code>setLogFactory</code> method to be used. + */ + protected Class logMethodSignature[] = + { LogFactory.class }; + + /** + * See getBaseClassLoader and initConfiguration. + */ + private boolean allowFlawedContext; + + /** + * See handleFlawedDiscovery and initConfiguration. + */ + private boolean allowFlawedDiscovery; + + /** + * See handleFlawedHierarchy and initConfiguration. + */ + private boolean allowFlawedHierarchy; + + // --------------------------------------------------------- Public Methods + + + /** + * Return the configuration attribute with the specified name (if any), + * or <code>null</code> if there is no such attribute. + * + * @param name Name of the attribute to return + */ + public Object getAttribute(String name) { + + return (attributes.get(name)); + + } + + + /** + * Return an array containing the names of all currently defined + * configuration attributes. If there are no such attributes, a zero + * length array is returned. + */ + public String[] getAttributeNames() { + + Vector names = new Vector(); + Enumeration keys = attributes.keys(); + while (keys.hasMoreElements()) { + names.addElement((String) keys.nextElement()); + } + String results[] = new String[names.size()]; + for (int i = 0; i < results.length; i++) { + results[i] = (String) names.elementAt(i); + } + return (results); + + } + + + /** + * Convenience method to derive a name from the specified class and + * call <code>getInstance(String)</code> with it. + * + * @param clazz Class for which a suitable Log name will be derived + * + * @exception LogConfigurationException if a suitable <code>Log</code> + * instance cannot be returned + */ + public Log getInstance(Class clazz) throws LogConfigurationException { + + return (getInstance(clazz.getName())); + + } + + + /** + * <p>Construct (if necessary) and return a <code>Log</code> instance, + * using the factory's current set of configuration attributes.</p> + * + * <p><strong>NOTE</strong> - Depending upon the implementation of + * the <code>LogFactory</code> you are using, the <code>Log</code> + * instance you are returned may or may not be local to the current + * application, and may or may not be returned again on a subsequent + * call with the same name argument.</p> + * + * @param name Logical name of the <code>Log</code> instance to be + * returned (the meaning of this name is only known to the underlying + * logging implementation that is being wrapped) + * + * @exception LogConfigurationException if a suitable <code>Log</code> + * instance cannot be returned + */ + public Log getInstance(String name) throws LogConfigurationException { + + Log instance = (Log) instances.get(name); + if (instance == null) { + instance = newInstance(name); + instances.put(name, instance); + } + return (instance); + + } + + + /** + * Release any internal references to previously created + * {@link org.apache.commons.logging.Log} + * instances returned by this factory. This is useful in environments + * like servlet containers, which implement application reloading by + * throwing away a ClassLoader. Dangling references to objects in that + * class loader would prevent garbage collection. + */ + public void release() { + + logDiagnostic("Releasing all known loggers"); + instances.clear(); + } + + + /** + * Remove any configuration attribute associated with the specified name. + * If there is no such attribute, no action is taken. + * + * @param name Name of the attribute to remove + */ + public void removeAttribute(String name) { + + attributes.remove(name); + + } + + + /** + * Set the configuration attribute with the specified name. Calling + * this with a <code>null</code> value is equivalent to calling + * <code>removeAttribute(name)</code>. + * <p> + * This method can be used to set logging configuration programmatically + * rather than via system properties. It can also be used in code running + * within a container (such as a webapp) to configure behaviour on a + * per-component level instead of globally as system properties would do. + * To use this method instead of a system property, call + * <pre> + * LogFactory.getFactory().setAttribute(...) + * </pre> + * This must be done before the first Log object is created; configuration + * changes after that point will be ignored. + * <p> + * This method is also called automatically if LogFactory detects a + * commons-logging.properties file; every entry in that file is set + * automatically as an attribute here. + * + * @param name Name of the attribute to set + * @param value Value of the attribute to set, or <code>null</code> + * to remove any setting for this attribute + */ + public void setAttribute(String name, Object value) { + + if (logConstructor != null) { + logDiagnostic("setAttribute: call too late; configuration already performed."); + } + + if (value == null) { + attributes.remove(name); + } else { + attributes.put(name, value); + } + + if (name.equals(TCCL_KEY)) { + useTCCL = Boolean.valueOf(value.toString()).booleanValue(); + } + + } + + + // ------------------------------------------------------ + // Static Methods + // + // These methods only defined as workarounds for a java 1.2 bug; + // theoretically none of these are needed. + // ------------------------------------------------------ + + /** + * Gets the context classloader. + * This method is a workaround for a java 1.2 compiler bug. + * @since 1.1 + */ + protected static ClassLoader getContextClassLoader() throws LogConfigurationException { + return LogFactory.getContextClassLoader(); + } + + + /** + * Workaround for bug in Java1.2; in theory this method is not needed. + * See LogFactory.isDiagnosticsEnabled. + */ + protected static boolean isDiagnosticsEnabled() { + return LogFactory.isDiagnosticsEnabled(); + } + + + /** + * Workaround for bug in Java1.2; in theory this method is not needed. + * See LogFactory.getClassLoader. + * @since 1.1 + */ + protected static ClassLoader getClassLoader(Class clazz) { + return LogFactory.getClassLoader(clazz); + } + + + // ------------------------------------------------------ Protected Methods + + /** + * Calculate and cache a string that uniquely identifies this instance, + * including which classloader the object was loaded from. + * <p> + * This string will later be prefixed to each "internal logging" message + * emitted, so that users can clearly see any unexpected behaviour. + * <p> + * Note that this method does not detect whether internal logging is + * enabled or not, nor where to output stuff if it is; that is all + * handled by the parent LogFactory class. This method just computes + * its own unique prefix for log messages. + */ + private void initDiagnostics() { + // It would be nice to include an identifier of the context classloader + // that this LogFactoryImpl object is responsible for. However that + // isn't possible as that information isn't available. It is possible + // to figure this out by looking at the logging from LogFactory to + // see the context & impl ids from when this object was instantiated, + // in order to link the impl id output as this object's prefix back to + // the context it is intended to manage. + // Note that this prefix should be kept consistent with that + // in LogFactory. + Class clazz = this.getClass(); + ClassLoader classLoader = getClassLoader(clazz); + String classLoaderName; + try { + if (classLoader == null) { + classLoaderName = "BOOTLOADER"; + } else { + classLoaderName = objectId(classLoader); + } + } catch(SecurityException e) { + classLoaderName = "UNKNOWN"; + } + diagnosticPrefix = "[LogFactoryImpl@" + System.identityHashCode(this) + " from " + classLoaderName + "] "; + } + + + /** + * Output a diagnostic message to a user-specified destination (if the + * user has enabled diagnostic logging). + * + * @param msg diagnostic message + * @since 1.1 + */ + protected void logDiagnostic(String msg) { + if (isDiagnosticsEnabled()) { + logRawDiagnostic(diagnosticPrefix + msg); + } + } + + /** + * Return the fully qualified Java classname of the {@link Log} + * implementation we will be using. + * + * @deprecated Never invoked by this class; subclasses should not assume + * it will be. + */ + protected String getLogClassName() { + + if (logClassName == null) { + discoverLogImplementation(getClass().getName()); + } + + return logClassName; + } + + + /** + * <p>Return the <code>Constructor</code> that can be called to instantiate + * new {@link org.apache.commons.logging.Log} instances.</p> + * + * <p><strong>IMPLEMENTATION NOTE</strong> - Race conditions caused by + * calling this method from more than one thread are ignored, because + * the same <code>Constructor</code> instance will ultimately be derived + * in all circumstances.</p> + * + * @exception LogConfigurationException if a suitable constructor + * cannot be returned + * + * @deprecated Never invoked by this class; subclasses should not assume + * it will be. + */ + protected Constructor getLogConstructor() + throws LogConfigurationException { + + // Return the previously identified Constructor (if any) + if (logConstructor == null) { + discoverLogImplementation(getClass().getName()); + } + + return logConstructor; + } + + + /** + * Is <em>JDK 1.3 with Lumberjack</em> logging available? + * + * @deprecated Never invoked by this class; subclasses should not assume + * it will be. + */ + protected boolean isJdk13LumberjackAvailable() { + return isLogLibraryAvailable( + "Jdk13Lumberjack", + "org.apache.commons.logging.impl.Jdk13LumberjackLogger"); + } + + + /** + * <p>Return <code>true</code> if <em>JDK 1.4 or later</em> logging + * is available. Also checks that the <code>Throwable</code> class + * supports <code>getStackTrace()</code>, which is required by + * Jdk14Logger.</p> + * + * @deprecated Never invoked by this class; subclasses should not assume + * it will be. + */ + protected boolean isJdk14Available() { + return isLogLibraryAvailable( + "Jdk14", + "org.apache.commons.logging.impl.Jdk14Logger"); + } + + + /** + * Is a <em>Log4J</em> implementation available? + * + * @deprecated Never invoked by this class; subclasses should not assume + * it will be. + */ + protected boolean isLog4JAvailable() { + return isLogLibraryAvailable( + "Log4J", + LOGGING_IMPL_LOG4J_LOGGER); + } + + + /** + * Create and return a new {@link org.apache.commons.logging.Log} + * instance for the specified name. + * + * @param name Name of the new logger + * + * @exception LogConfigurationException if a new instance cannot + * be created + */ + protected Log newInstance(String name) throws LogConfigurationException { + + Log instance = null; + try { + if (logConstructor == null) { + instance = discoverLogImplementation(name); + } + else { + Object params[] = { name }; + instance = (Log) logConstructor.newInstance(params); + } + + if (logMethod != null) { + Object params[] = { this }; + logMethod.invoke(instance, params); + } + + return (instance); + + } catch (LogConfigurationException lce) { + + // this type of exception means there was a problem in discovery + // and we've already output diagnostics about the issue, etc.; + // just pass it on + throw (LogConfigurationException) lce; + + } catch (InvocationTargetException e) { + // A problem occurred invoking the Constructor or Method + // previously discovered + Throwable c = e.getTargetException(); + if (c != null) { + throw new LogConfigurationException(c); + } else { + throw new LogConfigurationException(e); + } + } catch (Throwable t) { + // A problem occurred invoking the Constructor or Method + // previously discovered + throw new LogConfigurationException(t); + } + } + + + // ------------------------------------------------------ Private Methods + + /** + * Utility method to check whether a particular logging library is + * present and available for use. Note that this does <i>not</i> + * affect the future behaviour of this class. + */ + private boolean isLogLibraryAvailable(String name, String classname) { + if (isDiagnosticsEnabled()) { + logDiagnostic("Checking for '" + name + "'."); + } + try { + Log log = createLogFromClass( + classname, + this.getClass().getName(), // dummy category + false); + + if (log == null) { + if (isDiagnosticsEnabled()) { + logDiagnostic("Did not find '" + name + "'."); + } + return false; + } else { + if (isDiagnosticsEnabled()) { + logDiagnostic("Found '" + name + "'."); + } + return true; + } + } catch(LogConfigurationException e) { + if (isDiagnosticsEnabled()) { + logDiagnostic("Logging system '" + name + "' is available but not useable."); + } + return false; + } + } + + /** + * Attempt to find an attribute (see method setAttribute) or a + * system property with the provided name and return its value. + * <p> + * The attributes associated with this object are checked before + * system properties in case someone has explicitly called setAttribute, + * or a configuration property has been set in a commons-logging.properties + * file. + * + * @return the value associated with the property, or null. + */ + private String getConfigurationValue(String property) { + if (isDiagnosticsEnabled()) { + logDiagnostic("[ENV] Trying to get configuration for item " + property); + } + + Object valueObj = getAttribute(property); + if (valueObj != null) { + if (isDiagnosticsEnabled()) { + logDiagnostic("[ENV] Found LogFactory attribute [" + valueObj + "] for " + property); + } + return valueObj.toString(); + } + + if (isDiagnosticsEnabled()) { + logDiagnostic("[ENV] No LogFactory attribute found for " + property); + } + + try { + String value = System.getProperty(property); + if (value != null) { + if (isDiagnosticsEnabled()) { + logDiagnostic("[ENV] Found system property [" + value + "] for " + property); + } + return value; + } + + if (isDiagnosticsEnabled()) { + logDiagnostic("[ENV] No system property found for property " + property); + } + } catch (SecurityException e) { + if (isDiagnosticsEnabled()) { + logDiagnostic("[ENV] Security prevented reading system property " + property); + } + } + + if (isDiagnosticsEnabled()) { + logDiagnostic("[ENV] No configuration defined for item " + property); + } + + return null; + } + + /** + * Get the setting for the user-configurable behaviour specified by key. + * If nothing has explicitly been set, then return dflt. + */ + private boolean getBooleanConfiguration(String key, boolean dflt) { + String val = getConfigurationValue(key); + if (val == null) + return dflt; + return Boolean.valueOf(val).booleanValue(); + } + + /** + * Initialize a number of variables that control the behaviour of this + * class and that can be tweaked by the user. This is done when the first + * logger is created, not in the constructor of this class, because we + * need to give the user a chance to call method setAttribute in order to + * configure this object. + */ + private void initConfiguration() { + allowFlawedContext = getBooleanConfiguration(ALLOW_FLAWED_CONTEXT_PROPERTY, true); + allowFlawedDiscovery = getBooleanConfiguration(ALLOW_FLAWED_DISCOVERY_PROPERTY, true); + allowFlawedHierarchy = getBooleanConfiguration(ALLOW_FLAWED_HIERARCHY_PROPERTY, true); + } + + + /** + * Attempts to create a Log instance for the given category name. + * Follows the discovery process described in the class javadoc. + * + * @param logCategory the name of the log category + * + * @throws LogConfigurationException if an error in discovery occurs, + * or if no adapter at all can be instantiated + */ + private Log discoverLogImplementation(String logCategory) + throws LogConfigurationException + { + if (isDiagnosticsEnabled()) { + logDiagnostic("Discovering a Log implementation..."); + } + + initConfiguration(); + + Log result = null; + + // See if the user specified the Log implementation to use + String specifiedLogClassName = findUserSpecifiedLogClassName(); + + if (specifiedLogClassName != null) { + if (isDiagnosticsEnabled()) { + logDiagnostic("Attempting to load user-specified log class '" + + specifiedLogClassName + "'..."); + } + + result = createLogFromClass(specifiedLogClassName, + logCategory, + true); + if (result == null) { + StringBuffer messageBuffer = new StringBuffer("User-specified log class '"); + messageBuffer.append(specifiedLogClassName); + messageBuffer.append("' cannot be found or is not useable."); + + // Mistyping or misspelling names is a common fault. + // Construct a good error message, if we can + if (specifiedLogClassName != null) { + informUponSimilarName(messageBuffer, specifiedLogClassName, LOGGING_IMPL_LOG4J_LOGGER); + informUponSimilarName(messageBuffer, specifiedLogClassName, LOGGING_IMPL_JDK14_LOGGER); + informUponSimilarName(messageBuffer, specifiedLogClassName, LOGGING_IMPL_LUMBERJACK_LOGGER); + informUponSimilarName(messageBuffer, specifiedLogClassName, LOGGING_IMPL_SIMPLE_LOGGER); + } + throw new LogConfigurationException(messageBuffer.toString()); + } + + return result; + } + + // No user specified log; try to discover what's on the classpath + // + // Note that we deliberately loop here over classesToDiscover and + // expect method createLogFromClass to loop over the possible source + // classloaders. The effect is: + // for each discoverable log adapter + // for each possible classloader + // see if it works + // + // It appears reasonable at first glance to do the opposite: + // for each possible classloader + // for each discoverable log adapter + // see if it works + // + // The latter certainly has advantages for user-installable logging + // libraries such as log4j; in a webapp for example this code should + // first check whether the user has provided any of the possible + // logging libraries before looking in the parent classloader. + // Unfortunately, however, Jdk14Logger will always work in jvm>=1.4, + // and SimpleLog will always work in any JVM. So the loop would never + // ever look for logging libraries in the parent classpath. Yet many + // users would expect that putting log4j there would cause it to be + // detected (and this is the historical JCL behaviour). So we go with + // the first approach. A user that has bundled a specific logging lib + // in a webapp should use a commons-logging.properties file or a + // service file in META-INF to force use of that logging lib anyway, + // rather than relying on discovery. + + if (isDiagnosticsEnabled()) { + logDiagnostic( + "No user-specified Log implementation; performing discovery" + + " using the standard supported logging implementations..."); + } + for(int i=0; (i<classesToDiscover.length) && (result == null); ++i) { + result = createLogFromClass(classesToDiscover[i], logCategory, true); + } + + if (result == null) { + throw new LogConfigurationException + ("No suitable Log implementation"); + } + + return result; + } + + + /** + * Appends message if the given name is similar to the candidate. + * @param messageBuffer <code>StringBuffer</code> the message should be appended to, + * not null + * @param name the (trimmed) name to be test against the candidate, not null + * @param candidate the candidate name (not null) + */ + private void informUponSimilarName(final StringBuffer messageBuffer, final String name, + final String candidate) { + if (name.equals(candidate)) { + // Don't suggest a name that is exactly the same as the one the + // user tried... + return; + } + + // If the user provides a name that is in the right package, and gets + // the first 5 characters of the adapter class right (ignoring case), + // then suggest the candidate adapter class name. + if (name.regionMatches(true, 0, candidate, 0, PKG_LEN + 5)) { + messageBuffer.append(" Did you mean '"); + messageBuffer.append(candidate); + messageBuffer.append("'?"); + } + } + + + /** + * Checks system properties and the attribute map for + * a Log implementation specified by the user under the + * property names {@link #LOG_PROPERTY} or {@link #LOG_PROPERTY_OLD}. + * + * @return classname specified by the user, or <code>null</code> + */ + private String findUserSpecifiedLogClassName() + { + if (isDiagnosticsEnabled()) { + logDiagnostic("Trying to get log class from attribute '" + LOG_PROPERTY + "'"); + } + String specifiedClass = (String) getAttribute(LOG_PROPERTY); + + if (specifiedClass == null) { // @deprecated + if (isDiagnosticsEnabled()) { + logDiagnostic("Trying to get log class from attribute '" + + LOG_PROPERTY_OLD + "'"); + } + specifiedClass = (String) getAttribute(LOG_PROPERTY_OLD); + } + + if (specifiedClass == null) { + if (isDiagnosticsEnabled()) { + logDiagnostic("Trying to get log class from system property '" + + LOG_PROPERTY + "'"); + } + try { + specifiedClass = System.getProperty(LOG_PROPERTY); + } catch (SecurityException e) { + if (isDiagnosticsEnabled()) { + logDiagnostic("No access allowed to system property '" + + LOG_PROPERTY + "' - " + e.getMessage()); + } + } + } + + if (specifiedClass == null) { // @deprecated + if (isDiagnosticsEnabled()) { + logDiagnostic("Trying to get log class from system property '" + + LOG_PROPERTY_OLD + "'"); + } + try { + specifiedClass = System.getProperty(LOG_PROPERTY_OLD); + } catch (SecurityException e) { + if (isDiagnosticsEnabled()) { + logDiagnostic("No access allowed to system property '" + + LOG_PROPERTY_OLD + "' - " + e.getMessage()); + } + } + } + + // Remove any whitespace; it's never valid in a classname so its + // presence just means a user mistake. As we know what they meant, + // we may as well strip the spaces. + if (specifiedClass != null) { + specifiedClass = specifiedClass.trim(); + } + + return specifiedClass; + } + + + /** + * Attempts to load the given class, find a suitable constructor, + * and instantiate an instance of Log. + * + * @param logAdapterClassName classname of the Log implementation + * + * @param logCategory argument to pass to the Log implementation's + * constructor + * + * @param affectState <code>true</code> if this object's state should + * be affected by this method call, <code>false</code> otherwise. + * + * @return an instance of the given class, or null if the logging + * library associated with the specified adapter is not available. + * + * @throws LogConfigurationException if there was a serious error with + * configuration and the handleFlawedDiscovery method decided this + * problem was fatal. + */ + private Log createLogFromClass(String logAdapterClassName, + String logCategory, + boolean affectState) + throws LogConfigurationException { + + if (isDiagnosticsEnabled()) { + logDiagnostic("Attempting to instantiate '" + logAdapterClassName + "'"); + } + + Object[] params = { logCategory }; + Log logAdapter = null; + Constructor constructor = null; + + Class logAdapterClass = null; + ClassLoader currentCL = getBaseClassLoader(); + + for(;;) { + // Loop through the classloader hierarchy trying to find + // a viable classloader. + logDiagnostic( + "Trying to load '" + + logAdapterClassName + + "' from classloader " + + objectId(currentCL)); + try { + if (isDiagnosticsEnabled()) { + // Show the location of the first occurrence of the .class file + // in the classpath. This is the location that ClassLoader.loadClass + // will load the class from -- unless the classloader is doing + // something weird. + URL url; + String resourceName = logAdapterClassName.replace('.', '/') + ".class"; + if (currentCL != null) { + url = currentCL.getResource(resourceName ); + } else { + url = ClassLoader.getSystemResource(resourceName + ".class"); + } + + if (url == null) { + logDiagnostic("Class '" + logAdapterClassName + "' [" + resourceName + "] cannot be found."); + } else { + logDiagnostic("Class '" + logAdapterClassName + "' was found at '" + url + "'"); + } + } + + Class c = null; + try { + c = Class.forName(logAdapterClassName, true, currentCL); + } catch (ClassNotFoundException originalClassNotFoundException) { + // The current classloader was unable to find the log adapter + // in this or any ancestor classloader. There's no point in + // trying higher up in the hierarchy in this case.. + String msg = "" + originalClassNotFoundException.getMessage(); + logDiagnostic( + "The log adapter '" + + logAdapterClassName + + "' is not available via classloader " + + objectId(currentCL) + + ": " + + msg.trim()); + try { + // Try the class classloader. + // This may work in cases where the TCCL + // does not contain the code executed or JCL. + // This behaviour indicates that the application + // classloading strategy is not consistent with the + // Java 1.2 classloading guidelines but JCL can + // and so should handle this case. + c = Class.forName(logAdapterClassName); + } catch (ClassNotFoundException secondaryClassNotFoundException) { + // no point continuing: this adapter isn't available + msg = "" + secondaryClassNotFoundException.getMessage(); + logDiagnostic( + "The log adapter '" + + logAdapterClassName + + "' is not available via the LogFactoryImpl class classloader: " + + msg.trim()); + break; + } + } + + constructor = c.getConstructor(logConstructorSignature); + Object o = constructor.newInstance(params); + + // Note that we do this test after trying to create an instance + // [rather than testing Log.class.isAssignableFrom(c)] so that + // we don't complain about Log hierarchy problems when the + // adapter couldn't be instantiated anyway. + if (o instanceof Log) { + logAdapterClass = c; + logAdapter = (Log) o; + break; + } + + // Oops, we have a potential problem here. An adapter class + // has been found and its underlying lib is present too, but + // there are multiple Log interface classes available making it + // impossible to cast to the type the caller wanted. We + // certainly can't use this logger, but we need to know whether + // to keep on discovering or terminate now. + // + // The handleFlawedHierarchy method will throw + // LogConfigurationException if it regards this problem as + // fatal, and just return if not. + handleFlawedHierarchy(currentCL, c); + } catch (NoClassDefFoundError e) { + // We were able to load the adapter but it had references to + // other classes that could not be found. This simply means that + // the underlying logger library is not present in this or any + // ancestor classloader. There's no point in trying higher up + // in the hierarchy in this case.. + String msg = "" + e.getMessage(); + logDiagnostic( + "The log adapter '" + + logAdapterClassName + + "' is missing dependencies when loaded via classloader " + + objectId(currentCL) + + ": " + + msg.trim()); + break; + } catch (ExceptionInInitializerError e) { + // A static initializer block or the initializer code associated + // with a static variable on the log adapter class has thrown + // an exception. + // + // We treat this as meaning the adapter's underlying logging + // library could not be found. + String msg = "" + e.getMessage(); + logDiagnostic( + "The log adapter '" + + logAdapterClassName + + "' is unable to initialize itself when loaded via classloader " + + objectId(currentCL) + + ": " + + msg.trim()); + break; + } catch(LogConfigurationException e) { + // call to handleFlawedHierarchy above must have thrown + // a LogConfigurationException, so just throw it on + throw e; + } catch(Throwable t) { + // handleFlawedDiscovery will determine whether this is a fatal + // problem or not. If it is fatal, then a LogConfigurationException + // will be thrown. + handleFlawedDiscovery(logAdapterClassName, currentCL, t); + } + + if (currentCL == null) { + break; + } + + // try the parent classloader + currentCL = currentCL.getParent(); + } + + if ((logAdapter != null) && affectState) { + // We've succeeded, so set instance fields + this.logClassName = logAdapterClassName; + this.logConstructor = constructor; + + // Identify the <code>setLogFactory</code> method (if there is one) + try { + this.logMethod = logAdapterClass.getMethod("setLogFactory", + logMethodSignature); + logDiagnostic("Found method setLogFactory(LogFactory) in '" + + logAdapterClassName + "'"); + } catch (Throwable t) { + this.logMethod = null; + logDiagnostic( + "[INFO] '" + logAdapterClassName + + "' from classloader " + objectId(currentCL) + + " does not declare optional method " + + "setLogFactory(LogFactory)"); + } + + logDiagnostic( + "Log adapter '" + logAdapterClassName + + "' from classloader " + objectId(logAdapterClass.getClassLoader()) + + " has been selected for use."); + } + + return logAdapter; + } + + + /** + * Return the classloader from which we should try to load the logging + * adapter classes. + * <p> + * This method usually returns the context classloader. However if it + * is discovered that the classloader which loaded this class is a child + * of the context classloader <i>and</i> the allowFlawedContext option + * has been set then the classloader which loaded this class is returned + * instead. + * <p> + * The only time when the classloader which loaded this class is a + * descendant (rather than the same as or an ancestor of the context + * classloader) is when an app has created custom classloaders but + * failed to correctly set the context classloader. This is a bug in + * the calling application; however we provide the option for JCL to + * simply generate a warning rather than fail outright. + * + */ + private ClassLoader getBaseClassLoader() throws LogConfigurationException { + ClassLoader thisClassLoader = getClassLoader(LogFactoryImpl.class); + + if (useTCCL == false) { + return thisClassLoader; + } + + ClassLoader contextClassLoader = getContextClassLoader(); + + ClassLoader baseClassLoader = getLowestClassLoader( + contextClassLoader, thisClassLoader); + + if (baseClassLoader == null) { + // The two classloaders are not part of a parent child relationship. + // In some classloading setups (e.g. JBoss with its + // UnifiedLoaderRepository) this can still work, so if user hasn't + // forbidden it, just return the contextClassLoader. + if (allowFlawedContext) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "[WARNING] the context classloader is not part of a" + + " parent-child relationship with the classloader that" + + " loaded LogFactoryImpl."); + } + // If contextClassLoader were null, getLowestClassLoader() would + // have returned thisClassLoader. The fact we are here means + // contextClassLoader is not null, so we can just return it. + return contextClassLoader; + } + else { + throw new LogConfigurationException( + "Bad classloader hierarchy; LogFactoryImpl was loaded via" + + " a classloader that is not related to the current context" + + " classloader."); + } + } + + if (baseClassLoader != contextClassLoader) { + // We really should just use the contextClassLoader as the starting + // point for scanning for log adapter classes. However it is expected + // that there are a number of broken systems out there which create + // custom classloaders but fail to set the context classloader so + // we handle those flawed systems anyway. + if (allowFlawedContext) { + if (isDiagnosticsEnabled()) { + logDiagnostic( + "Warning: the context classloader is an ancestor of the" + + " classloader that loaded LogFactoryImpl; it should be" + + " the same or a descendant. The application using" + + " commons-logging should ensure the context classloader" + + " is used correctly."); + } + } else { + throw new LogConfigurationException( + "Bad classloader hierarchy; LogFactoryImpl was loaded via" + + " a classloader that is not related to the current context" + + " classloader."); + } + } + + return baseClassLoader; + } + + /** + * Given two related classloaders, return the one which is a child of + * the other. + * <p> + * @param c1 is a classloader (including the null classloader) + * @param c2 is a classloader (including the null classloader) + * + * @return c1 if it has c2 as an ancestor, c2 if it has c1 as an ancestor, + * and null if neither is an ancestor of the other. + */ + private ClassLoader getLowestClassLoader(ClassLoader c1, ClassLoader c2) { + // TODO: use AccessController when dealing with classloaders here + + if (c1 == null) + return c2; + + if (c2 == null) + return c1; + + ClassLoader current; + + // scan c1's ancestors to find c2 + current = c1; + while (current != null) { + if (current == c2) + return c1; + current = current.getParent(); + } + + // scan c2's ancestors to find c1 + current = c2; + while (current != null) { + if (current == c1) + return c2; + current = current.getParent(); + } + + return null; + } + + /** + * Generates an internal diagnostic logging of the discovery failure and + * then throws a <code>LogConfigurationException</code> that wraps + * the passed <code>Throwable</code>. + * + * @param logAdapterClassName is the class name of the Log implementation + * that could not be instantiated. Cannot be <code>null</code>. + * + * @param classLoader is the classloader that we were trying to load the + * logAdapterClassName from when the exception occurred. + * + * @param discoveryFlaw is the Throwable created by the classloader + * + * @throws LogConfigurationException ALWAYS + */ + private void handleFlawedDiscovery(String logAdapterClassName, + ClassLoader classLoader, + Throwable discoveryFlaw) { + + if (isDiagnosticsEnabled()) { + logDiagnostic("Could not instantiate Log '" + + logAdapterClassName + "' -- " + + discoveryFlaw.getClass().getName() + ": " + + discoveryFlaw.getLocalizedMessage()); + } + + if (!allowFlawedDiscovery) { + throw new LogConfigurationException(discoveryFlaw); + } + } + + + /** + * Report a problem loading the log adapter, then either return + * (if the situation is considered recoverable) or throw a + * LogConfigurationException. + * <p> + * There are two possible reasons why we successfully loaded the + * specified log adapter class then failed to cast it to a Log object: + * <ol> + * <li>the specific class just doesn't implement the Log interface + * (user screwed up), or + * <li> the specified class has bound to a Log class loaded by some other + * classloader; Log@classloaderX cannot be cast to Log@classloaderY. + * </ol> + * <p> + * Here we try to figure out which case has occurred so we can give the + * user some reasonable feedback. + * + * @param badClassLoader is the classloader we loaded the problem class from, + * ie it is equivalent to badClass.getClassLoader(). + * + * @param badClass is a Class object with the desired name, but which + * does not implement Log correctly. + * + * @throws LogConfigurationException when the situation + * should not be recovered from. + */ + private void handleFlawedHierarchy(ClassLoader badClassLoader, Class badClass) + throws LogConfigurationException { + + boolean implementsLog = false; + String logInterfaceName = Log.class.getName(); + Class interfaces[] = badClass.getInterfaces(); + for (int i = 0; i < interfaces.length; i++) { + if (logInterfaceName.equals(interfaces[i].getName())) { + implementsLog = true; + break; + } + } + + if (implementsLog) { + // the class does implement an interface called Log, but + // it is in the wrong classloader + if (isDiagnosticsEnabled()) { + try { + ClassLoader logInterfaceClassLoader = getClassLoader(Log.class); + logDiagnostic( + "Class '" + badClass.getName() + + "' was found in classloader " + + objectId(badClassLoader) + + ". It is bound to a Log interface which is not" + + " the one loaded from classloader " + + objectId(logInterfaceClassLoader)); + } catch (Throwable t) { + logDiagnostic( + "Error while trying to output diagnostics about" + + " bad class '" + badClass + "'"); + } + } + + if (!allowFlawedHierarchy) { + StringBuffer msg = new StringBuffer(); + msg.append("Terminating logging for this context "); + msg.append("due to bad log hierarchy. "); + msg.append("You have more than one version of '"); + msg.append(Log.class.getName()); + msg.append("' visible."); + if (isDiagnosticsEnabled()) { + logDiagnostic(msg.toString()); + } + throw new LogConfigurationException(msg.toString()); + } + + if (isDiagnosticsEnabled()) { + StringBuffer msg = new StringBuffer(); + msg.append("Warning: bad log hierarchy. "); + msg.append("You have more than one version of '"); + msg.append(Log.class.getName()); + msg.append("' visible."); + logDiagnostic(msg.toString()); + } + } else { + // this is just a bad adapter class + if (!allowFlawedDiscovery) { + StringBuffer msg = new StringBuffer(); + msg.append("Terminating logging for this context. "); + msg.append("Log class '"); + msg.append(badClass.getName()); + msg.append("' does not implement the Log interface."); + if (isDiagnosticsEnabled()) { + logDiagnostic(msg.toString()); + } + + throw new LogConfigurationException(msg.toString()); + } + + if (isDiagnosticsEnabled()) { + StringBuffer msg = new StringBuffer(); + msg.append("[WARNING] Log class '"); + msg.append(badClass.getName()); + msg.append("' does not implement the Log interface."); + logDiagnostic(msg.toString()); + } + } + } +} diff --git a/src/org/apache/commons/logging/impl/NoOpLog.java b/src/org/apache/commons/logging/impl/NoOpLog.java new file mode 100644 index 0000000..b698813 --- /dev/null +++ b/src/org/apache/commons/logging/impl/NoOpLog.java @@ -0,0 +1,106 @@ +/* + * Copyright 2001-2004 The Apache Software Foundation. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + + +package org.apache.commons.logging.impl; + + +import java.io.Serializable; +import org.apache.commons.logging.Log; + + +/** + * <p>Trivial implementation of Log that throws away all messages. No + * configurable system properties are supported.</p> + * + * @author <a href="mailto:sanders@apache.org">Scott Sanders</a> + * @author Rod Waldhoff + * @version $Id: NoOpLog.java 155426 2005-02-26 13:10:49Z dirkv $ + */ +public class NoOpLog implements Log, Serializable { + + /** Convenience constructor */ + public NoOpLog() { } + /** Base constructor */ + public NoOpLog(String name) { } + /** Do nothing */ + public void trace(Object message) { } + /** Do nothing */ + public void trace(Object message, Throwable t) { } + /** Do nothing */ + public void debug(Object message) { } + /** Do nothing */ + public void debug(Object message, Throwable t) { } + /** Do nothing */ + public void info(Object message) { } + /** Do nothing */ + public void info(Object message, Throwable t) { } + /** Do nothing */ + public void warn(Object message) { } + /** Do nothing */ + public void warn(Object message, Throwable t) { } + /** Do nothing */ + public void error(Object message) { } + /** Do nothing */ + public void error(Object message, Throwable t) { } + /** Do nothing */ + public void fatal(Object message) { } + /** Do nothing */ + public void fatal(Object message, Throwable t) { } + + /** + * Debug is never enabled. + * + * @return false + */ + public final boolean isDebugEnabled() { return false; } + + /** + * Error is never enabled. + * + * @return false + */ + public final boolean isErrorEnabled() { return false; } + + /** + * Fatal is never enabled. + * + * @return false + */ + public final boolean isFatalEnabled() { return false; } + + /** + * Info is never enabled. + * + * @return false + */ + public final boolean isInfoEnabled() { return false; } + + /** + * Trace is never enabled. + * + * @return false + */ + public final boolean isTraceEnabled() { return false; } + + /** + * Warn is never enabled. + * + * @return false + */ + public final boolean isWarnEnabled() { return false; } + +} diff --git a/src/org/apache/commons/logging/impl/SimpleLog.java b/src/org/apache/commons/logging/impl/SimpleLog.java new file mode 100644 index 0000000..6b643d3 --- /dev/null +++ b/src/org/apache/commons/logging/impl/SimpleLog.java @@ -0,0 +1,709 @@ +/* + * Copyright 2001-2004 The Apache Software Foundation. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + + +package org.apache.commons.logging.impl; + +import java.io.InputStream; +import java.io.Serializable; +import java.lang.reflect.InvocationTargetException; +import java.lang.reflect.Method; +import java.security.AccessController; +import java.security.PrivilegedAction; +import java.text.DateFormat; +import java.text.SimpleDateFormat; +import java.util.Date; +import java.util.Properties; + +import org.apache.commons.logging.Log; +import org.apache.commons.logging.LogConfigurationException; + +/** + * <p>Simple implementation of Log that sends all enabled log messages, + * for all defined loggers, to System.err. The following system properties + * are supported to configure the behavior of this logger:</p> + * <ul> + * <li><code>org.apache.commons.logging.simplelog.defaultlog</code> - + * Default logging detail level for all instances of SimpleLog. + * Must be one of ("trace", "debug", "info", "warn", "error", or "fatal"). + * If not specified, defaults to "info". </li> + * <li><code>org.apache.commons.logging.simplelog.log.xxxxx</code> - + * Logging detail level for a SimpleLog instance named "xxxxx". + * Must be one of ("trace", "debug", "info", "warn", "error", or "fatal"). + * If not specified, the default logging detail level is used.</li> + * <li><code>org.apache.commons.logging.simplelog.showlogname</code> - + * Set to <code>true</code> if you want the Log instance name to be + * included in output messages. Defaults to <code>false</code>.</li> + * <li><code>org.apache.commons.logging.simplelog.showShortLogname</code> - + * Set to <code>true</code> if you want the last component of the name to be + * included in output messages. Defaults to <code>true</code>.</li> + * <li><code>org.apache.commons.logging.simplelog.showdatetime</code> - + * Set to <code>true</code> if you want the current date and time + * to be included in output messages. Default is <code>false</code>.</li> + * <li><code>org.apache.commons.logging.simplelog.dateTimeFormat</code> - + * The date and time format to be used in the output messages. + * The pattern describing the date and time format is the same that is + * used in <code>java.text.SimpleDateFormat</code>. If the format is not + * specified or is invalid, the default format is used. + * The default format is <code>yyyy/MM/dd HH:mm:ss:SSS zzz</code>.</li> + * </ul> + * + * <p>In addition to looking for system properties with the names specified + * above, this implementation also checks for a class loader resource named + * <code>"simplelog.properties"</code>, and includes any matching definitions + * from this resource (if it exists).</p> + * + * @author <a href="mailto:sanders@apache.org">Scott Sanders</a> + * @author Rod Waldhoff + * @author Robert Burrell Donkin + * + * @version $Id: SimpleLog.java 399221 2006-05-03 09:20:24Z dennisl $ + */ +public class SimpleLog implements Log, Serializable { + + + // ------------------------------------------------------- Class Attributes + + /** All system properties used by <code>SimpleLog</code> start with this */ + static protected final String systemPrefix = + "org.apache.commons.logging.simplelog."; + + /** Properties loaded from simplelog.properties */ + static protected final Properties simpleLogProps = new Properties(); + + /** The default format to use when formating dates */ + static protected final String DEFAULT_DATE_TIME_FORMAT = + "yyyy/MM/dd HH:mm:ss:SSS zzz"; + + /** Include the instance name in the log message? */ + static protected boolean showLogName = false; + /** Include the short name ( last component ) of the logger in the log + * message. Defaults to true - otherwise we'll be lost in a flood of + * messages without knowing who sends them. + */ + static protected boolean showShortName = true; + /** Include the current time in the log message */ + static protected boolean showDateTime = false; + /** The date and time format to use in the log message */ + static protected String dateTimeFormat = DEFAULT_DATE_TIME_FORMAT; + /** Used to format times */ + static protected DateFormat dateFormatter = null; + + // ---------------------------------------------------- Log Level Constants + + + /** "Trace" level logging. */ + public static final int LOG_LEVEL_TRACE = 1; + /** "Debug" level logging. */ + public static final int LOG_LEVEL_DEBUG = 2; + /** "Info" level logging. */ + public static final int LOG_LEVEL_INFO = 3; + /** "Warn" level logging. */ + public static final int LOG_LEVEL_WARN = 4; + /** "Error" level logging. */ + public static final int LOG_LEVEL_ERROR = 5; + /** "Fatal" level logging. */ + public static final int LOG_LEVEL_FATAL = 6; + + /** Enable all logging levels */ + public static final int LOG_LEVEL_ALL = (LOG_LEVEL_TRACE - 1); + + /** Enable no logging levels */ + public static final int LOG_LEVEL_OFF = (LOG_LEVEL_FATAL + 1); + + // ------------------------------------------------------------ Initializer + + private static String getStringProperty(String name) { + String prop = null; + try { + prop = System.getProperty(name); + } catch (SecurityException e) { + ; // Ignore + } + return (prop == null) ? simpleLogProps.getProperty(name) : prop; + } + + private static String getStringProperty(String name, String dephault) { + String prop = getStringProperty(name); + return (prop == null) ? dephault : prop; + } + + private static boolean getBooleanProperty(String name, boolean dephault) { + String prop = getStringProperty(name); + return (prop == null) ? dephault : "true".equalsIgnoreCase(prop); + } + + // Initialize class attributes. + // Load properties file, if found. + // Override with system properties. + static { + // Add props from the resource simplelog.properties + InputStream in = getResourceAsStream("simplelog.properties"); + if(null != in) { + try { + simpleLogProps.load(in); + in.close(); + } catch(java.io.IOException e) { + // ignored + } + } + + showLogName = getBooleanProperty( systemPrefix + "showlogname", showLogName); + showShortName = getBooleanProperty( systemPrefix + "showShortLogname", showShortName); + showDateTime = getBooleanProperty( systemPrefix + "showdatetime", showDateTime); + + if(showDateTime) { + dateTimeFormat = getStringProperty(systemPrefix + "dateTimeFormat", + dateTimeFormat); + try { + dateFormatter = new SimpleDateFormat(dateTimeFormat); + } catch(IllegalArgumentException e) { + // If the format pattern is invalid - use the default format + dateTimeFormat = DEFAULT_DATE_TIME_FORMAT; + dateFormatter = new SimpleDateFormat(dateTimeFormat); + } + } + } + + + // ------------------------------------------------------------- Attributes + + /** The name of this simple log instance */ + protected String logName = null; + /** The current log level */ + protected int currentLogLevel; + /** The short name of this simple log instance */ + private String shortLogName = null; + + + // ------------------------------------------------------------ Constructor + + /** + * Construct a simple log with given name. + * + * @param name log name + */ + public SimpleLog(String name) { + + logName = name; + + // Set initial log level + // Used to be: set default log level to ERROR + // IMHO it should be lower, but at least info ( costin ). + setLevel(SimpleLog.LOG_LEVEL_INFO); + + // Set log level from properties + String lvl = getStringProperty(systemPrefix + "log." + logName); + int i = String.valueOf(name).lastIndexOf("."); + while(null == lvl && i > -1) { + name = name.substring(0,i); + lvl = getStringProperty(systemPrefix + "log." + name); + i = String.valueOf(name).lastIndexOf("."); + } + + if(null == lvl) { + lvl = getStringProperty(systemPrefix + "defaultlog"); + } + + if("all".equalsIgnoreCase(lvl)) { + setLevel(SimpleLog.LOG_LEVEL_ALL); + } else if("trace".equalsIgnoreCase(lvl)) { + setLevel(SimpleLog.LOG_LEVEL_TRACE); + } else if("debug".equalsIgnoreCase(lvl)) { + setLevel(SimpleLog.LOG_LEVEL_DEBUG); + } else if("info".equalsIgnoreCase(lvl)) { + setLevel(SimpleLog.LOG_LEVEL_INFO); + } else if("warn".equalsIgnoreCase(lvl)) { + setLevel(SimpleLog.LOG_LEVEL_WARN); + } else if("error".equalsIgnoreCase(lvl)) { + setLevel(SimpleLog.LOG_LEVEL_ERROR); + } else if("fatal".equalsIgnoreCase(lvl)) { + setLevel(SimpleLog.LOG_LEVEL_FATAL); + } else if("off".equalsIgnoreCase(lvl)) { + setLevel(SimpleLog.LOG_LEVEL_OFF); + } + + } + + + // -------------------------------------------------------- Properties + + /** + * <p> Set logging level. </p> + * + * @param currentLogLevel new logging level + */ + public void setLevel(int currentLogLevel) { + + this.currentLogLevel = currentLogLevel; + + } + + + /** + * <p> Get logging level. </p> + */ + public int getLevel() { + + return currentLogLevel; + } + + + // -------------------------------------------------------- Logging Methods + + + /** + * <p> Do the actual logging. + * This method assembles the message + * and then calls <code>write()</code> to cause it to be written.</p> + * + * @param type One of the LOG_LEVEL_XXX constants defining the log level + * @param message The message itself (typically a String) + * @param t The exception whose stack trace should be logged + */ + protected void log(int type, Object message, Throwable t) { + // Use a string buffer for better performance + StringBuffer buf = new StringBuffer(); + + // Append date-time if so configured + if(showDateTime) { + buf.append(dateFormatter.format(new Date())); + buf.append(" "); + } + + // Append a readable representation of the log level + switch(type) { + case SimpleLog.LOG_LEVEL_TRACE: buf.append("[TRACE] "); break; + case SimpleLog.LOG_LEVEL_DEBUG: buf.append("[DEBUG] "); break; + case SimpleLog.LOG_LEVEL_INFO: buf.append("[INFO] "); break; + case SimpleLog.LOG_LEVEL_WARN: buf.append("[WARN] "); break; + case SimpleLog.LOG_LEVEL_ERROR: buf.append("[ERROR] "); break; + case SimpleLog.LOG_LEVEL_FATAL: buf.append("[FATAL] "); break; + } + + // Append the name of the log instance if so configured + if( showShortName) { + if( shortLogName==null ) { + // Cut all but the last component of the name for both styles + shortLogName = logName.substring(logName.lastIndexOf(".") + 1); + shortLogName = + shortLogName.substring(shortLogName.lastIndexOf("/") + 1); + } + buf.append(String.valueOf(shortLogName)).append(" - "); + } else if(showLogName) { + buf.append(String.valueOf(logName)).append(" - "); + } + + // Append the message + buf.append(String.valueOf(message)); + + // Append stack trace if not null + if(t != null) { + buf.append(" <"); + buf.append(t.toString()); + buf.append(">"); + + java.io.StringWriter sw= new java.io.StringWriter(1024); + java.io.PrintWriter pw= new java.io.PrintWriter(sw); + t.printStackTrace(pw); + pw.close(); + buf.append(sw.toString()); + } + + // Print to the appropriate destination + write(buf); + + } + + + /** + * <p>Write the content of the message accumulated in the specified + * <code>StringBuffer</code> to the appropriate output destination. The + * default implementation writes to <code>System.err</code>.</p> + * + * @param buffer A <code>StringBuffer</code> containing the accumulated + * text to be logged + */ + protected void write(StringBuffer buffer) { + + System.err.println(buffer.toString()); + + } + + + /** + * Is the given log level currently enabled? + * + * @param logLevel is this level enabled? + */ + protected boolean isLevelEnabled(int logLevel) { + // log level are numerically ordered so can use simple numeric + // comparison + return (logLevel >= currentLogLevel); + } + + + // -------------------------------------------------------- Log Implementation + + + /** + * Logs a message with + * <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_DEBUG</code>. + * + * @param message to log + * @see org.apache.commons.logging.Log#debug(Object) + */ + public final void debug(Object message) { + + if (isLevelEnabled(SimpleLog.LOG_LEVEL_DEBUG)) { + log(SimpleLog.LOG_LEVEL_DEBUG, message, null); + } + } + + + /** + * Logs a message with + * <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_DEBUG</code>. + * + * @param message to log + * @param t log this cause + * @see org.apache.commons.logging.Log#debug(Object, Throwable) + */ + public final void debug(Object message, Throwable t) { + + if (isLevelEnabled(SimpleLog.LOG_LEVEL_DEBUG)) { + log(SimpleLog.LOG_LEVEL_DEBUG, message, t); + } + } + + + /** + * Logs a message with + * <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_TRACE</code>. + * + * @param message to log + * @see org.apache.commons.logging.Log#trace(Object) + */ + public final void trace(Object message) { + + if (isLevelEnabled(SimpleLog.LOG_LEVEL_TRACE)) { + log(SimpleLog.LOG_LEVEL_TRACE, message, null); + } + } + + + /** + * Logs a message with + * <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_TRACE</code>. + * + * @param message to log + * @param t log this cause + * @see org.apache.commons.logging.Log#trace(Object, Throwable) + */ + public final void trace(Object message, Throwable t) { + + if (isLevelEnabled(SimpleLog.LOG_LEVEL_TRACE)) { + log(SimpleLog.LOG_LEVEL_TRACE, message, t); + } + } + + + /** + * Logs a message with + * <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_INFO</code>. + * + * @param message to log + * @see org.apache.commons.logging.Log#info(Object) + */ + public final void info(Object message) { + + if (isLevelEnabled(SimpleLog.LOG_LEVEL_INFO)) { + log(SimpleLog.LOG_LEVEL_INFO,message,null); + } + } + + + /** + * Logs a message with + * <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_INFO</code>. + * + * @param message to log + * @param t log this cause + * @see org.apache.commons.logging.Log#info(Object, Throwable) + */ + public final void info(Object message, Throwable t) { + + if (isLevelEnabled(SimpleLog.LOG_LEVEL_INFO)) { + log(SimpleLog.LOG_LEVEL_INFO, message, t); + } + } + + + /** + * Logs a message with + * <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_WARN</code>. + * + * @param message to log + * @see org.apache.commons.logging.Log#warn(Object) + */ + public final void warn(Object message) { + + if (isLevelEnabled(SimpleLog.LOG_LEVEL_WARN)) { + log(SimpleLog.LOG_LEVEL_WARN, message, null); + } + } + + + /** + * Logs a message with + * <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_WARN</code>. + * + * @param message to log + * @param t log this cause + * @see org.apache.commons.logging.Log#warn(Object, Throwable) + */ + public final void warn(Object message, Throwable t) { + + if (isLevelEnabled(SimpleLog.LOG_LEVEL_WARN)) { + log(SimpleLog.LOG_LEVEL_WARN, message, t); + } + } + + + /** + * Logs a message with + * <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_ERROR</code>. + * + * @param message to log + * @see org.apache.commons.logging.Log#error(Object) + */ + public final void error(Object message) { + + if (isLevelEnabled(SimpleLog.LOG_LEVEL_ERROR)) { + log(SimpleLog.LOG_LEVEL_ERROR, message, null); + } + } + + + /** + * Logs a message with + * <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_ERROR</code>. + * + * @param message to log + * @param t log this cause + * @see org.apache.commons.logging.Log#error(Object, Throwable) + */ + public final void error(Object message, Throwable t) { + + if (isLevelEnabled(SimpleLog.LOG_LEVEL_ERROR)) { + log(SimpleLog.LOG_LEVEL_ERROR, message, t); + } + } + + + /** + * Log a message with + * <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_FATAL</code>. + * + * @param message to log + * @see org.apache.commons.logging.Log#fatal(Object) + */ + public final void fatal(Object message) { + + if (isLevelEnabled(SimpleLog.LOG_LEVEL_FATAL)) { + log(SimpleLog.LOG_LEVEL_FATAL, message, null); + } + } + + + /** + * Logs a message with + * <code>org.apache.commons.logging.impl.SimpleLog.LOG_LEVEL_FATAL</code>. + * + * @param message to log + * @param t log this cause + * @see org.apache.commons.logging.Log#fatal(Object, Throwable) + */ + public final void fatal(Object message, Throwable t) { + + if (isLevelEnabled(SimpleLog.LOG_LEVEL_FATAL)) { + log(SimpleLog.LOG_LEVEL_FATAL, message, t); + } + } + + + /** + * <p> Are debug messages currently enabled? </p> + * + * <p> This allows expensive operations such as <code>String</code> + * concatenation to be avoided when the message will be ignored by the + * logger. </p> + */ + public final boolean isDebugEnabled() { + + return isLevelEnabled(SimpleLog.LOG_LEVEL_DEBUG); + } + + + /** + * <p> Are error messages currently enabled? </p> + * + * <p> This allows expensive operations such as <code>String</code> + * concatenation to be avoided when the message will be ignored by the + * logger. </p> + */ + public final boolean isErrorEnabled() { + + return isLevelEnabled(SimpleLog.LOG_LEVEL_ERROR); + } + + + /** + * <p> Are fatal messages currently enabled? </p> + * + * <p> This allows expensive operations such as <code>String</code> + * concatenation to be avoided when the message will be ignored by the + * logger. </p> + */ + public final boolean isFatalEnabled() { + + return isLevelEnabled(SimpleLog.LOG_LEVEL_FATAL); + } + + + /** + * <p> Are info messages currently enabled? </p> + * + * <p> This allows expensive operations such as <code>String</code> + * concatenation to be avoided when the message will be ignored by the + * logger. </p> + */ + public final boolean isInfoEnabled() { + + return isLevelEnabled(SimpleLog.LOG_LEVEL_INFO); + } + + + /** + * <p> Are trace messages currently enabled? </p> + * + * <p> This allows expensive operations such as <code>String</code> + * concatenation to be avoided when the message will be ignored by the + * logger. </p> + */ + public final boolean isTraceEnabled() { + + return isLevelEnabled(SimpleLog.LOG_LEVEL_TRACE); + } + + + /** + * <p> Are warn messages currently enabled? </p> + * + * <p> This allows expensive operations such as <code>String</code> + * concatenation to be avoided when the message will be ignored by the + * logger. </p> + */ + public final boolean isWarnEnabled() { + + return isLevelEnabled(SimpleLog.LOG_LEVEL_WARN); + } + + + /** + * Return the thread context class loader if available. + * Otherwise return null. + * + * The thread context class loader is available for JDK 1.2 + * or later, if certain security conditions are met. + * + * @exception LogConfigurationException if a suitable class loader + * cannot be identified. + */ + private static ClassLoader getContextClassLoader() + { + ClassLoader classLoader = null; + + if (classLoader == null) { + try { + // Are we running on a JDK 1.2 or later system? + Method method = Thread.class.getMethod("getContextClassLoader", + (Class[]) null); + + // Get the thread context class loader (if there is one) + try { + classLoader = (ClassLoader)method.invoke(Thread.currentThread(), + (Object[]) null); + + } catch (IllegalAccessException e) { + ; // ignore + } catch (InvocationTargetException e) { + /** + * InvocationTargetException is thrown by 'invoke' when + * the method being invoked (getContextClassLoader) throws + * an exception. + * + * getContextClassLoader() throws SecurityException when + * the context class loader isn't an ancestor of the + * calling class's class loader, or if security + * permissions are restricted. + * + * In the first case (not related), we want to ignore and + * keep going. We cannot help but also ignore the second + * with the logic below, but other calls elsewhere (to + * obtain a class loader) will trigger this exception where + * we can make a distinction. + */ + if (e.getTargetException() instanceof SecurityException) { + ; // ignore + } else { + // Capture 'e.getTargetException()' exception for details + // alternate: log 'e.getTargetException()', and pass back 'e'. + throw new LogConfigurationException + ("Unexpected InvocationTargetException", e.getTargetException()); + } + } + } catch (NoSuchMethodException e) { + // Assume we are running on JDK 1.1 + ; // ignore + } + } + + if (classLoader == null) { + classLoader = SimpleLog.class.getClassLoader(); + } + + // Return the selected class loader + return classLoader; + } + + private static InputStream getResourceAsStream(final String name) + { + return (InputStream)AccessController.doPrivileged( + new PrivilegedAction() { + public Object run() { + ClassLoader threadCL = getContextClassLoader(); + + if (threadCL != null) { + return threadCL.getResourceAsStream(name); + } else { + return ClassLoader.getSystemResourceAsStream(name); + } + } + }); + } +} + diff --git a/src/org/apache/commons/logging/impl/WeakHashtable.java b/src/org/apache/commons/logging/impl/WeakHashtable.java new file mode 100644 index 0000000..e4749b6 --- /dev/null +++ b/src/org/apache/commons/logging/impl/WeakHashtable.java @@ -0,0 +1,478 @@ +/* + * Copyright 2004 The Apache Software Foundation. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + + +package org.apache.commons.logging.impl; + +import java.lang.ref.ReferenceQueue; +import java.lang.ref.WeakReference; +import java.util.*; + +/** + * <p>Implementation of <code>Hashtable</code> that uses <code>WeakReference</code>'s + * to hold its keys thus allowing them to be reclaimed by the garbage collector. + * The associated values are retained using strong references.</p> + * + * <p>This class follows the symantics of <code>Hashtable</code> as closely as + * possible. It therefore does not accept null values or keys.</p> + * + * <p><strong>Note:</strong> + * This is <em>not</em> intended to be a general purpose hash table replacement. + * This implementation is also tuned towards a particular purpose: for use as a replacement + * for <code>Hashtable</code> in <code>LogFactory</code>. This application requires + * good liveliness for <code>get</code> and <code>put</code>. Various tradeoffs + * have been made with this in mind. + * </p> + * <p> + * <strong>Usage:</strong> typical use case is as a drop-in replacement + * for the <code>Hashtable</code> used in <code>LogFactory</code> for J2EE enviroments + * running 1.3+ JVMs. Use of this class <i>in most cases</i> (see below) will + * allow classloaders to be collected by the garbage collector without the need + * to call {@link org.apache.commons.logging.LogFactory#release(ClassLoader) LogFactory.release(ClassLoader)}. + * </p> + * + * <p><code>org.apache.commons.logging.LogFactory</code> checks whether this class + * can be supported by the current JVM, and if so then uses it to store + * references to the <code>LogFactory</code> implementationd it loads + * (rather than using a standard Hashtable instance). + * Having this class used instead of <code>Hashtable</code> solves + * certain issues related to dynamic reloading of applications in J2EE-style + * environments. However this class requires java 1.3 or later (due to its use + * of <code>java.lang.ref.WeakReference</code> and associates). + * And by the way, this extends <code>Hashtable</code> rather than <code>HashMap</code> + * for backwards compatibility reasons. See the documentation + * for method <code>LogFactory.createFactoryStore</code> for more details.</p> + * + * <p>The reason all this is necessary is due to a issue which + * arises during hot deploy in a J2EE-like containers. + * Each component running in the container owns one or more classloaders; when + * the component loads a LogFactory instance via the component classloader + * a reference to it gets stored in the static LogFactory.factories member, + * keyed by the component's classloader so different components don't + * stomp on each other. When the component is later unloaded, the container + * sets the component's classloader to null with the intent that all the + * component's classes get garbage-collected. However there's still a + * reference to the component's classloader from a key in the "global" + * <code>LogFactory</code>'s factories member! If <code>LogFactory.release()</code> + * is called whenever component is unloaded, the classloaders will be correctly + * garbage collected; this <i>should</i> be done by any container that + * bundles commons-logging by default. However, holding the classloader + * references weakly ensures that the classloader will be garbage collected + * without the container performing this step. </p> + * + * <p> + * <strong>Limitations:</strong> + * There is still one (unusual) scenario in which a component will not + * be correctly unloaded without an explicit release. Though weak references + * are used for its keys, it is necessary to use strong references for its values. + * </p> + * + * <p> If the abstract class <code>LogFactory</code> is + * loaded by the container classloader but a subclass of + * <code>LogFactory</code> [LogFactory1] is loaded by the component's + * classloader and an instance stored in the static map associated with the + * base LogFactory class, then there is a strong reference from the LogFactory + * class to the LogFactory1 instance (as normal) and a strong reference from + * the LogFactory1 instance to the component classloader via + * <code>getClass().getClassLoader()</code>. This chain of references will prevent + * collection of the child classloader.</p> + * + * <p> + * Such a situation occurs when the commons-logging.jar is + * loaded by a parent classloader (e.g. a server level classloader in a + * servlet container) and a custom <code>LogFactory</code> implementation is + * loaded by a child classloader (e.g. a web app classloader).</p> + * + * <p>To avoid this scenario, ensure + * that any custom LogFactory subclass is loaded by the same classloader as + * the base <code>LogFactory</code>. Creating custom LogFactory subclasses is, + * however, rare. The standard LogFactoryImpl class should be sufficient + * for most or all users.</p> + * + * + * @author Brian Stansberry + * + * @since 1.1 + */ +public final class WeakHashtable extends Hashtable { + + /** + * The maximum number of times put() or remove() can be called before + * the map will be purged of all cleared entries. + */ + private static final int MAX_CHANGES_BEFORE_PURGE = 100; + + /** + * The maximum number of times put() or remove() can be called before + * the map will be purged of one cleared entry. + */ + private static final int PARTIAL_PURGE_COUNT = 10; + + /* ReferenceQueue we check for gc'd keys */ + private ReferenceQueue queue = new ReferenceQueue(); + /* Counter used to control how often we purge gc'd entries */ + private int changeCount = 0; + + /** + * Constructs a WeakHashtable with the Hashtable default + * capacity and load factor. + */ + public WeakHashtable() {} + + + /** + *@see Hashtable + */ + public boolean containsKey(Object key) { + // purge should not be required + Referenced referenced = new Referenced(key); + return super.containsKey(referenced); + } + + /** + *@see Hashtable + */ + public Enumeration elements() { + purge(); + return super.elements(); + } + + /** + *@see Hashtable + */ + public Set entrySet() { + purge(); + Set referencedEntries = super.entrySet(); + Set unreferencedEntries = new HashSet(); + for (Iterator it=referencedEntries.iterator(); it.hasNext();) { + Map.Entry entry = (Map.Entry) it.next(); + Referenced referencedKey = (Referenced) entry.getKey(); + Object key = referencedKey.getValue(); + Object value = entry.getValue(); + if (key != null) { + Entry dereferencedEntry = new Entry(key, value); + unreferencedEntries.add(dereferencedEntry); + } + } + return unreferencedEntries; + } + + /** + *@see Hashtable + */ + public Object get(Object key) { + // for performance reasons, no purge + Referenced referenceKey = new Referenced(key); + return super.get(referenceKey); + } + + /** + *@see Hashtable + */ + public Enumeration keys() { + purge(); + final Enumeration enumer = super.keys(); + return new Enumeration() { + public boolean hasMoreElements() { + return enumer.hasMoreElements(); + } + public Object nextElement() { + Referenced nextReference = (Referenced) enumer.nextElement(); + return nextReference.getValue(); + } + }; + } + + + /** + *@see Hashtable + */ + public Set keySet() { + purge(); + Set referencedKeys = super.keySet(); + Set unreferencedKeys = new HashSet(); + for (Iterator it=referencedKeys.iterator(); it.hasNext();) { + Referenced referenceKey = (Referenced) it.next(); + Object keyValue = referenceKey.getValue(); + if (keyValue != null) { + unreferencedKeys.add(keyValue); + } + } + return unreferencedKeys; + } + + /** + *@see Hashtable + */ + public Object put(Object key, Object value) { + // check for nulls, ensuring symantics match superclass + if (key == null) { + throw new NullPointerException("Null keys are not allowed"); + } + if (value == null) { + throw new NullPointerException("Null values are not allowed"); + } + + // for performance reasons, only purge every + // MAX_CHANGES_BEFORE_PURGE times + if (changeCount++ > MAX_CHANGES_BEFORE_PURGE) { + purge(); + changeCount = 0; + } + // do a partial purge more often + else if ((changeCount % PARTIAL_PURGE_COUNT) == 0) { + purgeOne(); + } + + Object result = null; + Referenced keyRef = new Referenced(key, queue); + return super.put(keyRef, value); + } + + /** + *@see Hashtable + */ + public void putAll(Map t) { + if (t != null) { + Set entrySet = t.entrySet(); + for (Iterator it=entrySet.iterator(); it.hasNext();) { + Map.Entry entry = (Map.Entry) it.next(); + put(entry.getKey(), entry.getValue()); + } + } + } + + /** + *@see Hashtable + */ + public Collection values() { + purge(); + return super.values(); + } + + /** + *@see Hashtable + */ + public Object remove(Object key) { + // for performance reasons, only purge every + // MAX_CHANGES_BEFORE_PURGE times + if (changeCount++ > MAX_CHANGES_BEFORE_PURGE) { + purge(); + changeCount = 0; + } + // do a partial purge more often + else if ((changeCount % PARTIAL_PURGE_COUNT) == 0) { + purgeOne(); + } + return super.remove(new Referenced(key)); + } + + /** + *@see Hashtable + */ + public boolean isEmpty() { + purge(); + return super.isEmpty(); + } + + /** + *@see Hashtable + */ + public int size() { + purge(); + return super.size(); + } + + /** + *@see Hashtable + */ + public String toString() { + purge(); + return super.toString(); + } + + /** + * @see Hashtable + */ + protected void rehash() { + // purge here to save the effort of rehashing dead entries + purge(); + super.rehash(); + } + + /** + * Purges all entries whose wrapped keys + * have been garbage collected. + */ + private void purge() { + synchronized (queue) { + WeakKey key; + while ((key = (WeakKey) queue.poll()) != null) { + super.remove(key.getReferenced()); + } + } + } + + /** + * Purges one entry whose wrapped key + * has been garbage collected. + */ + private void purgeOne() { + + synchronized (queue) { + WeakKey key = (WeakKey) queue.poll(); + if (key != null) { + super.remove(key.getReferenced()); + } + } + } + + /** Entry implementation */ + private final static class Entry implements Map.Entry { + + private final Object key; + private final Object value; + + private Entry(Object key, Object value) { + this.key = key; + this.value = value; + } + + public boolean equals(Object o) { + boolean result = false; + if (o != null && o instanceof Map.Entry) { + Map.Entry entry = (Map.Entry) o; + result = (getKey()==null ? + entry.getKey() == null : + getKey().equals(entry.getKey())) + && + (getValue()==null ? + entry.getValue() == null : + getValue().equals(entry.getValue())); + } + return result; + } + + public int hashCode() { + + return (getKey()==null ? 0 : getKey().hashCode()) ^ + (getValue()==null ? 0 : getValue().hashCode()); + } + + public Object setValue(Object value) { + throw new UnsupportedOperationException("Entry.setValue is not supported."); + } + + public Object getValue() { + return value; + } + + public Object getKey() { + return key; + } + } + + + /** Wrapper giving correct symantics for equals and hashcode */ + private final static class Referenced { + + private final WeakReference reference; + private final int hashCode; + + /** + * + * @throws NullPointerException if referant is <code>null</code> + */ + private Referenced(Object referant) { + reference = new WeakReference(referant); + // Calc a permanent hashCode so calls to Hashtable.remove() + // work if the WeakReference has been cleared + hashCode = referant.hashCode(); + } + + /** + * + * @throws NullPointerException if key is <code>null</code> + */ + private Referenced(Object key, ReferenceQueue queue) { + reference = new WeakKey(key, queue, this); + // Calc a permanent hashCode so calls to Hashtable.remove() + // work if the WeakReference has been cleared + hashCode = key.hashCode(); + + } + + public int hashCode() { + return hashCode; + } + + private Object getValue() { + return reference.get(); + } + + public boolean equals(Object o) { + boolean result = false; + if (o instanceof Referenced) { + Referenced otherKey = (Referenced) o; + Object thisKeyValue = getValue(); + Object otherKeyValue = otherKey.getValue(); + if (thisKeyValue == null) { + result = (otherKeyValue == null); + + // Since our hashcode was calculated from the original + // non-null referant, the above check breaks the + // hashcode/equals contract, as two cleared Referenced + // objects could test equal but have different hashcodes. + // We can reduce (not eliminate) the chance of this + // happening by comparing hashcodes. + if (result == true) { + result = (this.hashCode() == otherKey.hashCode()); + } + // In any case, as our c'tor does not allow null referants + // and Hashtable does not do equality checks between + // existing keys, normal hashtable operations should never + // result in an equals comparison between null referants + } + else + { + result = thisKeyValue.equals(otherKeyValue); + } + } + return result; + } + } + + /** + * WeakReference subclass that holds a hard reference to an + * associated <code>value</code> and also makes accessible + * the Referenced object holding it. + */ + private final static class WeakKey extends WeakReference { + + private final Referenced referenced; + + private WeakKey(Object key, + ReferenceQueue queue, + Referenced referenced) { + super(key, queue); + this.referenced = referenced; + } + + private Referenced getReferenced() { + return referenced; + } + } +} diff --git a/src/org/apache/commons/logging/impl/package.html b/src/org/apache/commons/logging/impl/package.html new file mode 100644 index 0000000..eb26b76 --- /dev/null +++ b/src/org/apache/commons/logging/impl/package.html @@ -0,0 +1,21 @@ +<!-- + + Copyright 2001-2004 The Apache Software Foundation. + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. + +--> + +<body> +<p>Concrete implementations of commons-logging wrapper APIs.</p> +</body> diff --git a/src/org/apache/commons/logging/package.html b/src/org/apache/commons/logging/package.html new file mode 100644 index 0000000..cfde4f0 --- /dev/null +++ b/src/org/apache/commons/logging/package.html @@ -0,0 +1,254 @@ +<!-- + + Copyright 2001-2004 The Apache Software Foundation. + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. + +--> + +<body> +<p>Simple wrapper API around multiple logging APIs.</p> + + +<h3>Overview</h3> + +<p>This package provides an API for logging in server-based applications that +can be used around a variety of different logging implementations, including +prebuilt support for the following:</p> +<ul> +<li><a href="http://logging.apache.org/log4j/">Log4J</a> (version 1.2 or later) + from Apache's Jakarta project. Each named <a href="Log.html">Log</a> + instance is connected to a corresponding Log4J Logger.</li> +<li><a href="http://java.sun.com/j2se/1.4/docs/guide/util/logging/index.html"> + JDK Logging API</a>, included in JDK 1.4 or later systems. Each named + <a href="Log.html">Log</a> instance is connected to a corresponding + <code>java.util.logging.Logger</code> instance.</li> +<li><a href="http://avalon.apache.org/logkit/">LogKit</a> from Apache's + Avalon project. Each named <a href="Log.html">Log</a> instance is + connected to a corresponding LogKit <code>Logger</code>.</li> +<li><a href="impl/NoOpLog.html">NoOpLog</a> implementation that simply swallows + all log output, for all named <a href="Log.html">Log</a> instances.</li> +<li><a href="impl/SimpleLog.html">SimpleLog</a> implementation that writes all + log output, for all named <a href="Log.html">Log</a> instances, to + System.err.</li> +</ul> + + +<h3>Quick Start Guide</h3> + +<p>For those impatient to just get on with it, the following example +illustrates the typical declaration and use of a logger that is named (by +convention) after the calling class: + +<pre> + import org.apache.commons.logging.Log; + import org.apache.commons.logging.LogFactory; + + public class Foo { + + private Log log = LogFactory.getLog(Foo.class); + + public void foo() { + ... + try { + if (log.isDebugEnabled()) { + log.debug("About to do something to object " + name); + } + name.bar(); + } catch (IllegalStateException e) { + log.error("Something bad happened to " + name, e); + } + ... + } +</pre> + +<p>Unless you configure things differently, all log output will be written +to System.err. Therefore, you really will want to review the remainder of +this page in order to understand how to configure logging for your +application.</p> + + +<h3>Configuring the Commons Logging Package</h3> + + +<h4>Choosing a <code>LogFactory</code> Implementation</h4> + +<p>From an application perspective, the first requirement is to retrieve an +object reference to the <code>LogFactory</code> instance that will be used +to create <code><a href="Log.html">Log</a></code> instances for this +application. This is normally accomplished by calling the static +<code>getFactory()</code> method. This method implements the following +discovery algorithm to select the name of the <code>LogFactory</code> +implementation class this application wants to use:</p> +<ul> +<li>Check for a system property named + <code>org.apache.commons.logging.LogFactory</code>.</li> +<li>Use the JDK 1.3 JAR Services Discovery mechanism (see + <a href="http://java.sun.com/j2se/1.3/docs/guide/jar/jar.html"> + http://java.sun.com/j2se/1.3/docs/guide/jar/jar.html</a> for + more information) to look for a resource named + <code>META-INF/services/org.apache.commons.logging.LogFactory</code> + whose first line is assumed to contain the desired class name.</li> +<li>Look for a properties file named <code>commons-logging.properties</code> + visible in the application class path, with a property named + <code>org.apache.commons.logging.LogFactory</code> defining the + desired implementation class name.</li> +<li>Fall back to a default implementation, which is described + further below.</li> +</ul> + +<p>If a <code>commons-logging.properties</code> file is found, all of the +properties defined there are also used to set configuration attributes on +the instantiated <code>LogFactory</code> instance.</p> + +<p>Once an implementation class name is selected, the corresponding class is +loaded from the current Thread context class loader (if there is one), or +from the class loader that loaded the <code>LogFactory</code> class itself +otherwise. This allows a copy of <code>commons-logging.jar</code> to be +shared in a multiple class loader environment (such as a servlet container), +but still allow each web application to provide its own <code>LogFactory</code> +implementation, if it so desires. An instance of this class will then be +created, and cached per class loader. + + +<h4>The Default <code>LogFactory</code> Implementation</h4> + +<p>The Logging Package APIs include a default <code>LogFactory</code> +implementation class (<a href="impl/LogFactoryImpl.html"> +org.apache.commons.logging.impl.LogFactoryImpl</a>) that is selected if no +other implementation class name can be discovered. Its primary purpose is +to create (as necessary) and return <a href="Log.html">Log</a> instances +in response to calls to the <code>getInstance()</code> method. The default +implementation uses the following rules:</p> +<ul> +<li>At most one <code>Log</code> instance of the same name will be created. + Subsequent <code>getInstance()</code> calls to the same + <code>LogFactory</code> instance, with the same name or <code>Class</code> + parameter, will return the same <code>Log</code> instance.</li> +<li>When a new <code>Log</code> instance must be created, the default + <code>LogFactory</code> implementation uses the following discovery + process: + <ul> + <li>Look for a configuration attribute of this factory named + <code>org.apache.commons.logging.Log</code> (for backwards + compatibility to pre-1.0 versions of this API, an attribute + <code>org.apache.commons.logging.log</code> is also consulted).</li> + <li>Look for a system property named + <code>org.apache.commons.logging.Log</code> (for backwards + compatibility to pre-1.0 versions of this API, a system property + <code>org.apache.commons.logging.log</code> is also consulted).</li> + <li>If the Log4J logging system is available in the application + class path, use the corresponding wrapper class + (<a href="impl/Log4JLogger.html">Log4JLogger</a>).</li> + <li>If the application is executing on a JDK 1.4 system, use + the corresponding wrapper class + (<a href="impl/Jdk14Logger.html">Jdk14Logger</a>).</li> + <li>Fall back to the default simple logging implementation + (<a href="impl/SimpleLog.html">SimpleLog</a>).</li> + </ul></li> +<li>Load the class of the specified name from the thread context class + loader (if any), or from the class loader that loaded the + <code>LogFactory</code> class otherwise.</li> +<li>Instantiate an instance of the selected <code>Log</code> + implementation class, passing the specified name as the single + argument to its constructor.</li> +</ul> + +<p>See the <a href="impl/SimpleLog.html">SimpleLog</a> JavaDocs for detailed +configuration information for this default implementation.</p> + + +<h4>Configuring the Underlying Logging System</h4> + +<p>The basic principle is that the user is totally responsible for the +configuration of the underlying logging system. +Commons-logging should not change the existing configuration.</p> + +<p>Each individual <a href="Log.html">Log</a> implementation may +support its own configuration properties. These will be documented in the +class descriptions for the corresponding implementation class.</p> + +<p>Finally, some <code>Log</code> implementations (such as the one for Log4J) +require an external configuration file for the entire logging environment. +This file should be prepared in a manner that is specific to the actual logging +technology being used.</p> + + +<h3>Using the Logging Package APIs</h3> + +<p>Use of the Logging Package APIs, from the perspective of an application +component, consists of the following steps:</p> +<ol> +<li>Acquire a reference to an instance of + <a href="Log.html">org.apache.commons.logging.Log</a>, by calling the + factory method + <a href="LogFactory.html#getInstance(java.lang.String)"> + LogFactory.getInstance(String name)</a>. Your application can contain + references to multiple loggers that are used for different + purposes. A typical scenario for a server application is to have each + major component of the server use its own Log instance.</li> +<li>Cause messages to be logged (if the corresponding detail level is enabled) + by calling appropriate methods (<code>trace()</code>, <code>debug()</code>, + <code>info()</code>, <code>warn()</code>, <code>error</code>, and + <code>fatal()</code>).</li> +</ol> + +<p>For convenience, <code>LogFactory</code> also offers a static method +<code>getLog()</code> that combines the typical two-step pattern:</p> +<pre> + Log log = LogFactory.getFactory().getInstance(Foo.class); +</pre> +<p>into a single method call:</p> +<pre> + Log log = LogFactory.getLog(Foo.class); +</pre> + +<p>For example, you might use the following technique to initialize and +use a <a href="Log.html">Log</a> instance in an application component:</p> +<pre> +import org.apache.commons.logging.Log; +import org.apache.commons.logging.LogFactory; + +public class MyComponent { + + protected Log log = + LogFactory.getLog(MyComponent.class); + + // Called once at startup time + public void start() { + ... + log.info("MyComponent started"); + ... + } + + // Called once at shutdown time + public void stop() { + ... + log.info("MyComponent stopped"); + ... + } + + // Called repeatedly to process a particular argument value + // which you want logged if debugging is enabled + public void process(String value) { + ... + // Do the string concatenation only if logging is enabled + if (log.isDebugEnabled()) + log.debug("MyComponent processing " + value); + ... + } + +} +</pre> + +</body> |