| /* |
| * Copyright 1999-2004 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.cocoon.servlet; |
| |
| import java.io.File; |
| import java.io.IOException; |
| import java.net.URL; |
| import java.net.URLClassLoader; |
| import java.net.URLStreamHandlerFactory; |
| |
| /** |
| * The <code>ParanoidClassLoader</code> reverses the search order for |
| * classes. It checks this classloader before it checks its parent. |
| * |
| * @author <a href="mailto:bloritsch@apache.org">Berin Loritsch</a> |
| * @author <a href="http://www.apache.org/~sylvain/">Sylvain Wallez</a> |
| * @version CVS $Id: ParanoidClassLoader.java,v 1.2 2004/03/05 13:02:02 bdelacretaz Exp $ |
| */ |
| |
| public class ParanoidClassLoader extends URLClassLoader { |
| |
| /** |
| * Default constructor has no parents or initial <code>URL</code>s. |
| */ |
| public ParanoidClassLoader() { |
| this(null, null, null); |
| } |
| |
| /** |
| * Alternate constructor to define a parent. |
| */ |
| public ParanoidClassLoader(final ClassLoader parent) { |
| this(new URL[0], parent, null); |
| } |
| |
| /** |
| * Alternate constructor to define initial <code>URL</code>s. |
| */ |
| public ParanoidClassLoader(final URL[] urls) { |
| this(urls, null, null); |
| } |
| |
| /** |
| * Alternate constructor to define a parent and initial |
| * <code>URL</code>s. |
| */ |
| public ParanoidClassLoader(final URL[] urls, final ClassLoader parent) { |
| this(urls, parent, null); |
| } |
| |
| /** |
| * Alternate constructor to define a parent, initial |
| * <code>URL</code>s, and a default |
| * <code>URLStreamHandlerFactory</code>. |
| */ |
| public ParanoidClassLoader(final URL[] urls, final ClassLoader parent, final URLStreamHandlerFactory factory) { |
| super(urls, parent, factory); |
| } |
| |
| /** |
| * Extends <code>URLClassLoader</code>'s initialization methods so |
| * we return a <code>ParanoidClassLoad</code> instead. |
| */ |
| public static final URLClassLoader newInstance(final URL[] urls) { |
| return new ParanoidClassLoader(urls); |
| } |
| |
| /** |
| * Extends <code>URLClassLoader</code>'s initialization methods so |
| * we return a <code>ParanoidClassLoad</code> instead. |
| */ |
| public static final URLClassLoader newInstance(final URL[] urls, final ClassLoader parent) { |
| return new ParanoidClassLoader(urls, parent); |
| } |
| |
| /** |
| * Loads the class from this <code>ClassLoader</class>. If the |
| * class does not exist in this one, we check the parent. Please |
| * note that this is the exact opposite of the |
| * <code>ClassLoader</code> spec. We use it to work around |
| * inconsistent class loaders from third party vendors. |
| * |
| * @param name the name of the class |
| * @param resolve if <code>true</code> then resolve the class |
| * @return the resulting <code>Class</code> object |
| * @exception ClassNotFoundException if the class could not be found |
| */ |
| public final Class loadClass(String name, boolean resolve) |
| throws ClassNotFoundException |
| { |
| // First check if it's already loaded |
| Class clazz = findLoadedClass(name); |
| |
| if (clazz == null) { |
| |
| try { |
| clazz = findClass(name); |
| //System.err.println("Paranoid load : " + name); |
| } catch (ClassNotFoundException cnfe) { |
| ClassLoader parent = getParent(); |
| if (parent != null) { |
| // Ask to parent ClassLoader (can also throw a CNFE). |
| clazz = parent.loadClass(name); |
| } else { |
| // Propagate exception |
| throw cnfe; |
| } |
| } |
| } |
| |
| if (resolve) { |
| resolveClass(clazz); |
| } |
| |
| return clazz; |
| } |
| |
| /** |
| * Gets a resource from this <code>ClassLoader</class>. If the |
| * resource does not exist in this one, we check the parent. |
| * Please note that this is the exact opposite of the |
| * <code>ClassLoader</code> spec. We use it to work around |
| * inconsistent class loaders from third party vendors. |
| * |
| * @param name of resource |
| */ |
| public final URL getResource(final String name) { |
| |
| URL resource = findResource(name); |
| ClassLoader parent = this.getParent(); |
| if (resource == null && parent != null) { |
| resource = parent.getResource(name); |
| } |
| |
| return resource; |
| } |
| |
| /** |
| * Adds a new directory of class files. |
| * |
| * @param file for jar or directory |
| * @throws IOException |
| */ |
| public final void addDirectory(File file) throws IOException { |
| this.addURL(file.getCanonicalFile().toURL()); |
| } |
| |
| /** |
| * Adds a new URL |
| */ |
| |
| public void addURL(URL url) { |
| super.addURL(url); |
| } |
| } |