001/*
002 * (C) Copyright 2006-2012 Nuxeo SA (http://nuxeo.com/) and contributors.
003 *
004 * All rights reserved. This program and the accompanying materials
005 * are made available under the terms of the GNU Lesser General Public License
006 * (LGPL) version 2.1 which accompanies this distribution, and is available at
007 * http://www.gnu.org/licenses/lgpl.html
008 *
009 * This library is distributed in the hope that it will be useful,
010 * but WITHOUT ANY WARRANTY; without even the implied warranty of
011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012 * Lesser General Public License for more details.
013 *
014 * Contributors:
015 *     bstefanescu, jcarsique
016 */
017package org.nuxeo.osgi.application;
018
019import java.lang.reflect.Method;
020import java.net.URL;
021
022/**
023 * @author <a href="mailto:bs@nuxeo.com">Bogdan Stefanescu</a>
024 * @since 5.4.2
025 */
026public class MutableClassLoaderDelegate implements MutableClassLoader {
027
028    protected final ClassLoader cl;
029
030    protected Method addURL;
031
032    public MutableClassLoaderDelegate(ClassLoader cl) throws IllegalArgumentException {
033        this.cl = cl;
034        Class<?> clazz = cl.getClass();
035        do {
036            try {
037                addURL = clazz.getDeclaredMethod("addURL", URL.class);
038            } catch (NoSuchMethodException e) {
039                clazz = clazz.getSuperclass();
040            } catch (SecurityException e) {
041                throw new IllegalArgumentException("Failed to adapt class loader: " + cl.getClass(), e);
042            }
043        } while (addURL == null && clazz != null);
044        if (addURL == null) {
045            throw new IllegalArgumentException("Incompatible class loader: " + cl.getClass()
046                    + ". ClassLoader must provide a method: addURL(URL url)");
047        }
048        addURL.setAccessible(true);
049    }
050
051    @Override
052    public void addURL(URL url) {
053        try {
054            addURL.invoke(cl, url);
055        } catch (ReflectiveOperationException e) {
056            throw new RuntimeException("Failed to add URL to class loader: " + url, e);
057        }
058    }
059
060    @Override
061    public ClassLoader getClassLoader() {
062        return cl;
063    }
064
065    @Override
066    public Class<?> loadClass(String startupClass) throws ClassNotFoundException {
067        return cl.loadClass(startupClass);
068    }
069
070}