Glassfish example source code file (EarClassLoader.java)

This example Glassfish source code file (EarClassLoader.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

classloader, classloader, classloaderholder, classloaderholder, delegatingclassloader, delegatingclassloader, earclassloader, earclassloader, earlibclassloader, exception, linkedlist, list, override, string, util

The Glassfish EarClassLoader.java source code

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * 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
 * 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
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 */

package org.glassfish.javaee.full.deployment;

import java.util.*;

import com.sun.enterprise.loader.ASURLClassLoader;
import org.glassfish.internal.api.DelegatingClassLoader;
import org.jvnet.hk2.component.PreDestroy;

/**
 * Simplistic class loader which will delegate to each module class loader in the order
 * they were added to the instance
 *
 * @author Jerome Dochez
 */
public class EarClassLoader extends ASURLClassLoader
{

    private List<ClassLoaderHolder> moduleClassLoaders = new LinkedList();
    boolean isPreDestroyCalled = false;

    public EarClassLoader(ClassLoader classLoader) {
        super(classLoader); 
    }

    public void addModuleClassLoader(String moduleName, ClassLoader cl) {
        moduleClassLoaders.add(new ClassLoaderHolder(moduleName, cl));
    }

    public ClassLoader getModuleClassLoader(String moduleName) {
        for (ClassLoaderHolder clh : moduleClassLoaders) {
            if (moduleName.equals(clh.moduleName)) {
                return clh.loader;
            }
        }
        return null;
    }

    @Override
    public void preDestroy() {
        if (isPreDestroyCalled) {
            return;
        }

        try {
            for (ClassLoaderHolder clh : moduleClassLoaders) {
                // destroy all the module classloaders
                if ( !(clh.loader instanceof EarLibClassLoader) &&  
                     !(clh.loader instanceof EarClassLoader) && 
                     !isRARCL(clh.loader)) {
                    try {
                        PreDestroy.class.cast(clh.loader).preDestroy();
                    } catch (Exception e) {
                        // ignore, the class loader does not need to be 
                        // explicitly stopped.
                    }
                }
            }

            // destroy itself
            super.preDestroy();

            //now destroy embedded Connector CLs
            DelegatingClassLoader dcl = (DelegatingClassLoader)this.getParent();
            for(DelegatingClassLoader.ClassFinder cf : dcl.getDelegates()){
                try {
                    PreDestroy.class.cast(cf).preDestroy();
                } catch (Exception e) {
                    // ignore, the class loader does not need to be 
                    // explicitly stopped.
                }
            }

            // now destroy the EarLibClassLoader
            PreDestroy.class.cast(this.getParent().getParent()).preDestroy();

            moduleClassLoaders = null;
        } catch (Exception e) {
            // ignore, the class loader does not need to be explicitely stopped.
        }

        isPreDestroyCalled = true;
    }

    private boolean isRARCL(ClassLoader loader) {
        DelegatingClassLoader connectorCL = (DelegatingClassLoader) this.getParent();
        return connectorCL.getDelegates().contains(loader);
    }

    private class ClassLoaderHolder {
        final ClassLoader loader;
        final String moduleName;

        private ClassLoaderHolder(String moduleName, ClassLoader loader) {
            this.loader = loader;
            this.moduleName = moduleName;
        }
    }

    @Override
    protected String getClassLoaderName() {
        return "EarClassLoader";
    }
}