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Diffstat (limited to 'src/org/apache/commons/logging/LogSource.java')
| -rw-r--r-- | src/org/apache/commons/logging/LogSource.java | 261 |
1 files changed, 261 insertions, 0 deletions
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()])); + } + + +} |