Glassfish example source code file (ACCAgentClassLoader.java)

This example Glassfish source code file (ACCAgentClassLoader.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Glassfish tags/keywords

accagentclassloader, accagentclassloader, classloader, exception, gfsystemuri, gfsystemuri, io, list, net, network, override, runtimeexception, runtimeexception, string, uri, url, url, util

The Glassfish ACCAgentClassLoader.java source code

/*
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 *
 * Copyright (c) 1997-2010 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:
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 * 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
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 * 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.appclient.client.acc.agent;

import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLClassLoader;
import java.net.URLStreamHandlerFactory;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;
import java.util.ListIterator;

/**
 * Used as the system class loader during app client launch.
 * <p>
 * The main role of this class loader is to find a splash screen image
 * that might be specified in the manifest of the app client.  Once the
 * ACC begins working it will create an ACCClassLoader for loading
 * client classes and locating client resources.
 *
 * @author tjquinn
 */
public class ACCAgentClassLoader extends URLClassLoader {

    private boolean isActive = true;

    public ACCAgentClassLoader(ClassLoader parent) {
        /*
         * This constructor is used by the VM to create a
         * system class loader (as specified by -Djava.system.class.loader
         * on the java command created from the appclient script).
         * <p>
         * Actually create two new loaders.  One will handle the GlassFish system JARs
         * and the second will temporarily handle the application resources -
         * typically for a splash screen.
         */
        super(userClassPath(),
                new URLClassLoader(GFSystemClassPath(), parent.getParent()));
    }

    public ACCAgentClassLoader(URL[] urls) {
        super(urls);
    }

    public ACCAgentClassLoader(URL[] urls, ClassLoader parent) {
        super(urls, parent);
    }

    public ACCAgentClassLoader(URL[] urls, ClassLoader parent, URLStreamHandlerFactory factory) {
        super(urls, parent, factory);
    }


    @Override
    public synchronized Class<?> loadClass(String name) throws ClassNotFoundException {
        if (isActive && isStillActive()) {
            return super.loadClass(name);
        } else {
            return getParent().loadClass(name);
        }
    }

    @Override
    public URL getResource(String name) {
        if (isActive && isStillActive()) {
            return super.getResource(name);
        } else {
            return getParent().getResource(name);
        }
    }

    @Override
    public Enumeration<URL> getResources(String name) throws IOException {
        if (isActive && isStillActive()) {
            return super.getResources(name);
        } else {
            return getParent().getResources(name);
        }
    }

    private boolean isStillActive() {
        if (isActive) {
            final String propValue = System.getProperty("org.glassfish.appclient.acc.agentLoaderDone");
            isActive = (propValue != null);
        }
        return isActive;
    }

    private static URL[] userClassPath() {
        final URI GFSystemURI = GFSystemURI();
        final List<URL> result = classPathToURLs(System.getProperty("java.class.path"));
        for (ListIterator<URL> it = result.listIterator(); it.hasNext();) {
            final URL url = it.next();
            try {
                if (url.toURI().equals(GFSystemURI)) {
                    it.remove();
                }
            } catch (URISyntaxException ex) {
                throw new RuntimeException(ex);
            }
        }

//        result.addAll(classPathToURLs(System.getenv("APPCPATH")));

        return result.toArray(new URL[result.size()]);
    }

    private static URL[] GFSystemClassPath() {
        try {
            return new URL[] {GFSystemURI().normalize().toURL()};
        } catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }

    private static URI GFSystemURI() {
        try {
            Class agentClass = Class.forName("org.glassfish.appclient.client.acc.agent.AppClientContainerAgent");
            return agentClass.getProtectionDomain().getCodeSource().getLocation().toURI().normalize();
        } catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }

    private static List<URL> classPathToURLs(final String classPath) {
        if (classPath == null) {
            return Collections.EMPTY_LIST;
        }
        final List<URL> result = new ArrayList();
        try {
            for (String classPathElement : classPath.split(File.pathSeparator)) {
                result.add(new File(classPathElement).toURI().normalize().toURL());
            }
            return result;
        } catch (Exception ex) {
            throw new RuntimeException(ex);
        }
    }
}