| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.openjpa.util; |
| |
| import java.security.AccessController; |
| |
| import org.apache.openjpa.lib.util.J2DoPrivHelper; |
| import org.apache.openjpa.lib.util.MultiClassLoader; |
| |
| /** |
| * Default class resolver implementation. |
| * |
| * @since 0.3.0 |
| * @author Abe White |
| */ |
| public class ClassResolverImpl |
| implements ClassResolver { |
| |
| @Override |
| public ClassLoader getClassLoader(Class<?> contextClass, ClassLoader envLoader) { |
| // get the context class' loader; if the class was loaded by the |
| // bootstrap loader, use the system classloader in the hopes that |
| // class.forName calls on it will find the bootstrap loader's cached |
| // class (the bootstrap loader is the parent of the system loader) |
| ClassLoader contextLoader = null; |
| if (contextClass != null) { |
| contextLoader = AccessController.doPrivileged( |
| J2DoPrivHelper.getClassLoaderAction(contextClass)); |
| if (contextLoader == null) |
| contextLoader = AccessController.doPrivileged( |
| J2DoPrivHelper.getSystemClassLoaderAction()); |
| } |
| |
| // if there is only one unique loader, just return it |
| ClassLoader threadLoader = AccessController.doPrivileged( |
| J2DoPrivHelper.getContextClassLoaderAction()); |
| if ((contextLoader == null || contextLoader == threadLoader) |
| && (envLoader == null || envLoader == threadLoader)) |
| return threadLoader; |
| |
| // construct a multi class loader that will delegate in the order |
| // described in section 12.5 of the spec |
| MultiClassLoader loader = AccessController |
| .doPrivileged(J2DoPrivHelper.newMultiClassLoaderAction()); |
| if (contextLoader != null) |
| loader.addClassLoader(contextLoader); |
| loader.addClassLoader(threadLoader); |
| if (envLoader != null) |
| loader.addClassLoader(envLoader); |
| return loader; |
| } |
| } |