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Glassfish example source code file (APIClassLoaderServiceImpl.java)
The Glassfish APIClassLoaderServiceImpl.java source code/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright (c) 2007-2010 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 com.sun.enterprise.v3.server; import com.sun.enterprise.module.Module; import com.sun.enterprise.module.ModulesRegistry; import com.sun.enterprise.module.ModuleLifecycleListener; import com.sun.enterprise.module.common_impl.CompositeEnumeration; import com.sun.logging.LogDomains; import org.jvnet.hk2.annotations.Inject; import org.jvnet.hk2.annotations.Service; import org.jvnet.hk2.component.PostConstruct; import java.io.IOException; import java.util.logging.Level; import java.util.logging.Logger; import java.util.*; import java.net.URL; /** * This class is responsible for creating a ClassLoader that can * load classes exported by any OSGi bundle in the system for public use. * Such classes include Java EE API, AMX API, appserv-ext API, etc. * CommonClassLoader delegates to this class loader.. * It does special treatment of META-INF/mailcap file. For such resources, * it searches all available bundles. * * @author Sanjeeb.Sahoo@Sun.COM */ @Service public class APIClassLoaderServiceImpl implements PostConstruct { /* * Implementation Note: * 1. This class depends on OSGi runtime, so not portable on HK2. * 2. APIClassLoader maintains a blacklist, i.e., classes and resources that could not be loaded to avoid * unnecessary delegation. It flushes that list everytime a new bundle is installed in the system. * This takes care of performance problem in typical production use of GlassFish. */ private ClassLoader theAPIClassLoader; @Inject ModulesRegistry mr; private static final String APIExporterModuleName = "GlassFish-Application-Common-Module"; // NOI18N private static final String MAILCAP = "META-INF/mailcap"; final static Logger logger = LogDomains.getLogger(APIClassLoaderServiceImpl.class, LogDomains.LOADER_LOGGER); private Module APIModule; public void postConstruct() { try { createAPIClassLoader(); } catch (IOException e) { throw new RuntimeException(e); } } private void createAPIClassLoader() throws IOException { APIModule = mr.getModules(APIExporterModuleName).iterator().next(); assert (APIModule != null); final ClassLoader apiModuleLoader = APIModule.getClassLoader(); /* * We don't directly retrun APIModule's class loader, because * that class loader does not delegate to the parent. Instead, it * relies on OSGi bundle to load the classes. That behavior is * fine if we want to honor OSGi classloading semantics. APIClassLoader * wants to use delegation model so that we don't have to set * bootdelegation=* for OSGi bundles. * Since the parent of bundle classloader will have glassfish launching classes, felix or any other * OSGi framework classes and their dependencies, we don't want to delegate to such a class loader. * Instead, we delegate to JRE's extension class loader if we don't find any class via APIModuleLoader. * With this, user can actually embed a different version of Felix as part of their app. */ theAPIClassLoader = new APIClassLoader(apiModuleLoader, getExtensionClassLoader()); logger.logp(Level.FINE, "APIClassLoaderService", "createAPIClassLoader", "APIClassLoader = {0}", new Object[]{theAPIClassLoader}); } private ClassLoader getExtensionClassLoader() { return ClassLoader.getSystemClassLoader().getParent(); } public ClassLoader getAPIClassLoader() { return theAPIClassLoader; } private class APIClassLoader extends ClassLoader { // list of not found classes and resources. // the string represents resource name, so foo/Bar.class for foo.Bar private Set<String> blacklist; private final ClassLoader apiModuleLoader; /** * This method takes two classloaders which is unusual. Both the class loaders are consulted, * so they both are delegates, but depending on the class/resource being requested, one is preferred * over the other. The second argument is the classic parent class loader, where as the first one * is the OSGi gateway classloader. For all java.* names, we consult only the parent loader. * For any other names, we first consult the OSGi gateway loader and then parent. See more comments in * loadClass() method implementation of this class. * @param apiModuleLoader ClassLoader corresponding to the APIModule * @param parent ClassLoader that's consulted for all java.* classes and for classes * not found via apiModuleLoader */ public APIClassLoader(ClassLoader apiModuleLoader, ClassLoader parent) { super(parent); this.apiModuleLoader = apiModuleLoader; blacklist = new HashSet<String>(); // add a listener to manage blacklist in APIClassLoader mr.register(new ModuleLifecycleListener() { public void moduleInstalled(Module module) { clearBlackList(); } public void moduleResolved(Module module) { } public void moduleStarted(Module module) { } public void moduleStopped(Module module) { } public void moduleUpdated(Module module) { clearBlackList(); } }); } @Override public Class<?> loadClass(String name) throws ClassNotFoundException { return loadClass(name, false); } @Override protected synchronized Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException { // First check if we know this can't be loaded final String resourceName = convertToResourceName(name); if (isBlackListed(resourceName)) { throw new ClassNotFoundException(name); } // Then check if the class has already been loaded Class c = findLoadedClass(name); if (c == null) { if (!name.startsWith("java.")) { // java classes always come from parent try { c = apiModuleLoader.loadClass(name); // we ignore the resolution flag } catch (ClassNotFoundException cnfe) { } } if (c == null) { // Call super class implementation which takes care of // delegating to parent. try { c = super.loadClass(name, resolve); } catch (ClassNotFoundException e) { addToBlackList(resourceName); throw e; } } } return c; } @Override public URL getResource(String name) { if (isBlackListed(name)) return null; URL url = null; if (!name.startsWith("java/")) { if (name.equals(MAILCAP)) { // punch in for META-INF/mailcap files. // see issue #8426 for (Module m : mr.getModules()) { if ((url = m.getClassLoader().getResource(name)) != null) { break; } } } else { url = apiModuleLoader.getResource(name); } } if (url == null) { // Either requested resource belongs to java/ namespace or // it was not found in any of the bundles, so call // super class implementation which will delegate to parent. url = super.getResource(name); } if (url == null) { addToBlackList(name); } return url; } @Override public Enumeration<URL> getResources(String name) throws IOException { List<Enumeration Other Glassfish examples (source code examples)Here is a short list of links related to this Glassfish APIClassLoaderServiceImpl.java source code file: |
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