001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *  http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019
020package org.apache.xbean.osgi.bundle.util.equinox;
021
022import java.io.IOException;
023import java.net.URL;
024import java.net.URLClassLoader;
025import java.util.Enumeration;
026
027import org.apache.xbean.osgi.bundle.util.BundleResourceHelper;
028import org.apache.xbean.osgi.bundle.util.DelegatingBundle;
029import org.apache.xbean.osgi.bundle.util.DelegatingBundleReference;
030import org.osgi.framework.Bundle;
031import org.osgi.framework.BundleReference;
032
033/**
034 * ClassLoader for a {@link Bundle}. 
035 * <br/>
036 * This ClassLoader implementation extends the {@link URLClassLoader} and converts resource &quot;bundle&quot;
037 * URLs (found in directories or embedded jar files) into regular <tt>jar</tt> URLs. 
038 * This ClassLoader implementation will only work on Equinox framework.
039 * 
040 * @version $Rev: 1163514 $ $Date: 2011-08-31 09:37:38 +0200 (Wed, 31 Aug 2011) $
041 */
042public class EquinoxBundleClassLoader extends URLClassLoader implements DelegatingBundleReference {
043
044    private final Bundle bundle;
045    private final BundleResourceHelper resourceHelper;
046    
047    public EquinoxBundleClassLoader(Bundle bundle) {      
048        this(bundle, 
049             BundleResourceHelper.getSearchWiredBundles(true), 
050             BundleResourceHelper.getConvertResourceUrls(true));
051    }
052    
053    public EquinoxBundleClassLoader(Bundle bundle, boolean searchWiredBundles, boolean convertResourceUrls) {
054        super(new URL[] {});
055        this.bundle = bundle;
056        this.resourceHelper = new EquinoxBundleResourceHelper(bundle, searchWiredBundles, convertResourceUrls);
057    }
058    
059    @Override
060    public String toString() {
061        return "[EquinoxBundleClassLoader] " + bundle;
062    }
063  
064    @Override
065    protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
066        Class clazz = bundle.loadClass(name);
067        if (resolve) {
068            resolveClass(clazz);
069        }
070        return clazz;
071    }
072    
073    @Override
074    public URL getResource(String name) {
075        return resourceHelper.getResource(name);
076    }
077    
078    @Override
079    public Enumeration<URL> findResources(String name) throws IOException {
080        return resourceHelper.getResources(name);
081    }
082    
083    public void setSearchWiredBundles(boolean search) {
084        resourceHelper.setSearchWiredBundles(search);
085    }
086    
087    public boolean getSearchWiredBundles() {
088        return resourceHelper.getSearchWiredBundles();
089    }
090           
091    public void setConvertResourceUrls(boolean convert) {
092        resourceHelper.setConvertResourceUrls(convert);
093    }
094    
095    public boolean getConvertResourceUrls() {
096        return resourceHelper.getConvertResourceUrls();
097    }
098    
099    /**
100     * Return the bundle associated with this classloader.
101     * 
102     * In most cases the bundle associated with the classloader is a regular framework bundle. 
103     * However, in some cases the bundle associated with the classloader is a {@link DelegatingBundle}.
104     * In such cases, the <tt>unwrap</tt> parameter controls whether this function returns the
105     * {@link DelegatingBundle} instance or the main application bundle backing with the {@link DelegatingBundle}.
106     *
107     * @param unwrap If true and if the bundle associated with this classloader is a {@link DelegatingBundle}, 
108     *        this function will return the main application bundle backing with the {@link DelegatingBundle}. 
109     *        Otherwise, the bundle associated with this classloader is returned as is.
110     * @return The bundle associated with this classloader.
111     */
112    public Bundle getBundle(boolean unwrap) {
113        if (unwrap && bundle instanceof DelegatingBundle) {
114            return ((DelegatingBundle) bundle).getMainBundle();
115        }
116        return bundle;
117    }
118    
119    /**
120     * Return the bundle associated with this classloader.
121     * 
122     * This method calls {@link #getBundle(boolean) getBundle(true)} and therefore always returns a regular 
123     * framework bundle.  
124     * <br><br>
125     * Note: Some libraries use {@link BundleReference#getBundle()} to obtain a bundle for the given 
126     * classloader and expect the returned bundle instance to be work with any OSGi API. Some of these API might
127     * not work if {@link DelegatingBundle} is returned. That is why this function will always return
128     * a regular framework bundle. See {@link #getBundle(boolean)} for more information.
129     *
130     * @return The bundle associated with this classloader.
131     */
132    public Bundle getBundle() {
133        return getBundle(true);
134    }
135    
136    @Override
137    public int hashCode() {
138        return bundle.hashCode();
139    }
140
141    @Override
142    public boolean equals(Object other) {
143        if (other == this) {
144            return true;
145        }
146        if (other == null || !other.getClass().equals(getClass())) {
147            return false;
148        }
149        EquinoxBundleClassLoader otherBundleClassLoader = (EquinoxBundleClassLoader) other;
150        return this.bundle == otherBundleClassLoader.bundle;
151    }
152    
153}