org.glassfish.osgijavaeebase.BundleClassLoader Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of osgi-javaee-base Show documentation
There is a newer version: 1.0.9
/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2009-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package org.glassfish.osgijavaeebase;

import org.osgi.framework.Bundle;

import java.io.IOException;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.Enumeration;
import java.util.NoSuchElementException;

/**
 * This is a delegating class loader.
 * It always delegates to OSGi bundle's class loader.
 * ClassLoader.defineClass() is never called in the context of this class.
 * There will never be a class for which getClassLoader()
 * would return this class loader.
 * It overrides loadClass(), getResource() and getResources() as opposed to
 * their findXYZ() equivalents so that the OSGi export control mechanism
 * is enforced even for classes and resources available in the system/boot
 * class loader.
 *
 * @author [email protected]
 */
public class BundleClassLoader extends ClassLoader
{
    private Bundle bundle;

    public BundleClassLoader(Bundle b)
    {
        super(Bundle.class.getClassLoader());
        this.bundle = b;
    }

    @Override
    public synchronized Class loadClass(final String name, boolean resolve) throws ClassNotFoundException
    {
        return bundle.loadClass(name);
    }

    @Override
    public URL getResource(String name)
    {
        return bundle.getResource(name);
    }

    @Override
    public Enumeration getResources(String name) throws IOException
    {
        Enumeration resources = bundle.getResources(name);
        if (resources == null)
        {
            // This check is needed, because ClassLoader.getResources()
            // expects us to return an empty enumeration.
            resources = new Enumeration()
            {

                public boolean hasMoreElements()
                {
                    return false;
                }

                public URL nextElement()
                {
                    throw new NoSuchElementException();
                }
            };
        }
        return resources;
    }
}