/* * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. * * Copyright (c) 1997-2011 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.appserv; import java.io.IOException; import java.lang.reflect.Field; import java.net.URLClassLoader; import java.util.ArrayList; import java.util.HashMap; import java.util.Stack; import java.util.Vector; import java.util.jar.JarFile; import java.util.logging.Level; import java.util.logging.Logger; import java.text.MessageFormat; import sun.misc.URLClassPath; import com.sun.logging.LogDomains; /** * Provides utility functions related to URLClassLoaders or subclasses of it. * * W A R N I N G * *This class uses undocumented, unpublished, private data structures inside *java.net.URLClassLoader and sun.misc.URLClassPath. Use with extreme caution. * * @author tjquinn */ public class ClassLoaderUtil { /** records whether initialization has been completed */ private static boolean isInitialized = false; /** names of classes and fields of interest for closing the loader's jar files */ private static final String URLCLASSLOADER_UCP_FIELD_NAME = "ucp"; private static final String URLCLASSPATH_LOADERS_FIELD_NAME = "loaders"; // ArrayList of URLClassPath.Loader private static final String URLCLASSPATH_URLS_FIELD_NAME = "urls"; // Stack of URL private static final String URLCLASSPATH_LMAP_FIELD_NAME = "lmap"; // HashMap of String -> URLClassPath.Loader private static final String URLCLASSPATH_JARLOADER_INNER_CLASS_NAME = "sun.misc.URLClassPath$JarLoader"; private static final String URLCLASSPATH_JARLOADER_JARFILE_FIELD_NAME = "jar"; /* Fields used during processing - they can be set up once and then used repeatedly */ private static Field jcpField; private static Field loadersField; private static Field urlsField; private static Field lmapField; private static Class jarLoaderInnerClass; private static Field jarFileField; private static boolean initDone = false; /** *Initializes the class. *
*Each utility method should invoke init() before doing their own work *to make sure the initialization is done. *@throws any Throwable detected during static init. */ private static void init() throws Throwable { if ( ! initDone) { initForClosingJars(); initDone = true; } } /** *Sets up variables used in closing a loader's jar files. *@throws NoSuchFieldException in case a field of interest is not found where expected */ private static void initForClosingJars() throws NoSuchFieldException { jcpField = getField(URLClassLoader.class, URLCLASSLOADER_UCP_FIELD_NAME); loadersField = getField(URLClassPath.class, URLCLASSPATH_LOADERS_FIELD_NAME); urlsField = getField(URLClassPath.class, URLCLASSPATH_URLS_FIELD_NAME); lmapField = getField(URLClassPath.class, URLCLASSPATH_LMAP_FIELD_NAME); jarLoaderInnerClass = getInnerClass(URLClassPath.class, URLCLASSPATH_JARLOADER_INNER_CLASS_NAME); jarFileField = getField(jarLoaderInnerClass, URLCLASSPATH_JARLOADER_JARFILE_FIELD_NAME); } /** *Retrieves a Field object for a given field on the specified class, having *set it accessible. *@param cls the Class on which the field is expected to be defined *@param fieldName the name of the field of interest *@throws NoSuchFieldException in case of any error retriving information about the field */ private static Field getField(Class cls, String fieldName) throws NoSuchFieldException { try { Field field = cls.getDeclaredField(fieldName); field.setAccessible(true); return field; } catch (NoSuchFieldException nsfe) { NoSuchFieldException e = new NoSuchFieldException(getMessage("classloaderutil.errorGettingField", fieldName)); e.initCause(nsfe); throw e; } } /** *Retrieves a given inner class definition from the specified outer class. *@param cls the outer Class *@param innerClassName the fully-qualified name of the inner class of interest */ private static Class getInnerClass(Class cls, String innerClassName) { Class result = null; Class[] innerClasses = cls.getDeclaredClasses(); for (Class c : innerClasses) { if (c.getName().equals(innerClassName)) { result = c; break; } } return result; } /** *Releases resources held by the URLClassLoader. Notably, close the jars *opened by the loader. This does not prevent the class loader from *continuing to return classes it has already resolved. *@param classLoader the instance of URLClassLoader (or a subclass) *@return array of IOExceptions reporting jars that failed to close */ public static void releaseLoader(URLClassLoader classLoader) { releaseLoader(classLoader, null); } /** *Releases resources held by the URLClassLoader. Notably, close the jars *opened by the loader. This does not prevent the class loader from *continuing to return classes it has alrady resolved although that is not *what we intend to happen. Initializes and updates the Vector of *jars that have been successfully closed. *
*Any errors are logged.
*@param classLoader the instance of URLClassLoader (or a subclass)
*@param jarsClosed a Vector of Strings that will contain the names of jars
* successfully closed; can be null if the caller does not need the information returned
*@return array of IOExceptions reporting jars that failed to close; null
*indicates that an error other than an IOException occurred attempting to
*release the loader; empty indicates a successful release; non-empty
*indicates at least one error attempting to close an open jar.
*/
public static IOException [] releaseLoader(URLClassLoader classLoader, Vector