1 files changed, 145 insertions, 0 deletions
diff --git a/media/mca/filterfw/java/android/filterfw/core/FilterFactory.java b/media/mca/filterfw/java/android/filterfw/core/FilterFactory.java
new file mode 100644
index 0000000..779df99
--- /dev/null
+++ b/media/mca/filterfw/java/android/filterfw/core/FilterFactory.java
@@ -0,0 +1,145 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * 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 android.filterfw.core;
+
+import android.filterfw.core.Filter;
+import android.util.Log;
+
+import dalvik.system.PathClassLoader;
+
+import java.lang.reflect.Constructor;
+import java.lang.ClassLoader;
+import java.lang.Thread;
+import java.util.HashSet;
+
+/**
+ * @hide
+ */
+public class FilterFactory {
+
+    private static FilterFactory mSharedFactory;
+    private HashSet<String> mPackages = new HashSet<String>();
+
+    private static ClassLoader mCurrentClassLoader;
+    private static HashSet<String> mLibraries;
+    private static Object mClassLoaderGuard;
+
+    static {
+        mCurrentClassLoader = Thread.currentThread().getContextClassLoader();
+        mLibraries = new HashSet<String>();
+        mClassLoaderGuard = new Object();
+    }
+
+    private static final String TAG = "FilterFactory";
+    private static boolean mLogVerbose = Log.isLoggable(TAG, Log.VERBOSE);
+
+    public static FilterFactory sharedFactory() {
+        if (mSharedFactory == null) {
+            mSharedFactory = new FilterFactory();
+        }
+        return mSharedFactory;
+    }
+
+    /**
+     * Adds a new Java library to the list to be scanned for filters.
+     * libraryPath must be an absolute path of the jar file.  This needs to be
+     * static because only one classloader per process can open a shared native
+     * library, which a filter may well have.
+     */
+    public static void addFilterLibrary(String libraryPath) {
+        if (mLogVerbose) Log.v(TAG, "Adding filter library " + libraryPath);
+        synchronized(mClassLoaderGuard) {
+            if (mLibraries.contains(libraryPath)) {
+                if (mLogVerbose) Log.v(TAG, "Library already added");
+                return;
+            }
+            mLibraries.add(libraryPath);
+            // Chain another path loader to the current chain
+            mCurrentClassLoader = new PathClassLoader(libraryPath, mCurrentClassLoader);
+        }
+    }
+
+    public void addPackage(String packageName) {
+        if (mLogVerbose) Log.v(TAG, "Adding package " + packageName);
+        /* TODO: This should use a getPackage call in the caller's context, but no such method exists.
+        Package pkg = Package.getPackage(packageName);
+        if (pkg == null) {
+            throw new IllegalArgumentException("Unknown filter package '" + packageName + "'!");
+        }
+        */
+        mPackages.add(packageName);
+    }
+
+    public Filter createFilterByClassName(String className, String filterName) {
+        if (mLogVerbose) Log.v(TAG, "Looking up class " + className);
+        Class filterClass = null;
+
+        // Look for the class in the imported packages
+        for (String packageName : mPackages) {
+            try {
+                if (mLogVerbose) Log.v(TAG, "Trying "+packageName + "." + className);
+                synchronized(mClassLoaderGuard) {
+                    filterClass = mCurrentClassLoader.loadClass(packageName + "." + className);
+                }
+            } catch (ClassNotFoundException e) {
+                continue;
+            }
+            // Exit loop if class was found.
+            if (filterClass != null) {
+                break;
+            }
+        }
+        if (filterClass == null) {
+            throw new IllegalArgumentException("Unknown filter class '" + className + "'!");
+        }
+        return createFilterByClass(filterClass, filterName);
+    }
+
+    public Filter createFilterByClass(Class filterClass, String filterName) {
+        // Make sure this is a Filter subclass
+        try {
+            filterClass.asSubclass(Filter.class);
+        } catch (ClassCastException e) {
+            throw new IllegalArgumentException("Attempting to allocate class '" + filterClass
+                + "' which is not a subclass of Filter!");
+        }
+
+        // Look for the correct constructor
+        Constructor filterConstructor = null;
+        try {
+            filterConstructor = filterClass.getConstructor(String.class);
+        } catch (NoSuchMethodException e) {
+            throw new IllegalArgumentException("The filter class '" + filterClass
+                + "' does not have a constructor of the form <init>(String name)!");
+        }
+
+        // Construct the filter
+        Filter filter = null;
+        try {
+            filter = (Filter)filterConstructor.newInstance(filterName);
+        } catch (Throwable t) {
+            // Condition checked below
+        }
+
+        if (filter == null) {
+            throw new IllegalArgumentException("Could not construct the filter '"
+                + filterName + "'!");
+        }
+        return filter;
+    }
+}