From e5b7380c874745c989d1816b8f552504f038e1bc Mon Sep 17 00:00:00 2001 From: lresende Date: Thu, 26 Sep 2013 20:33:20 +0000 Subject: 2.0 branch for possible maintenance release git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@1526672 13f79535-47bb-0310-9956-ffa450edef68 --- .../sca/extensibility/ClassLoaderContext.java | 253 +++++++++++++++++++++ 1 file changed, 253 insertions(+) create mode 100644 sca-java-2.x/branches/2.0/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ClassLoaderContext.java (limited to 'sca-java-2.x/branches/2.0/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ClassLoaderContext.java') diff --git a/sca-java-2.x/branches/2.0/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ClassLoaderContext.java b/sca-java-2.x/branches/2.0/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ClassLoaderContext.java new file mode 100644 index 0000000000..598c897402 --- /dev/null +++ b/sca-java-2.x/branches/2.0/modules/extensibility/src/main/java/org/apache/tuscany/sca/extensibility/ClassLoaderContext.java @@ -0,0 +1,253 @@ +/* + * 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.tuscany.sca.extensibility; + +import java.io.IOException; +import java.net.URL; +import java.security.PrivilegedAction; +import java.security.PrivilegedActionException; +import java.security.PrivilegedExceptionAction; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Enumeration; +import java.util.List; + +import org.apache.tuscany.sca.extensibility.impl.ClassLoaderDelegate; + +/** + * A utility that controls context class loaders + * @tuscany.spi.extension.asclient + */ +public class ClassLoaderContext { + private ClassLoader classLoader; + + /** + * Create a context with the parent classloader and a list of service types that can be discovered + * by the {@link ServiceDiscovery} + * @param parent + * @param discovery + * @param serviceTypes + */ + public ClassLoaderContext(ClassLoader parent, ServiceDiscovery discovery, Class... serviceTypes) { + this(parent, getClassLoaders(discovery, serviceTypes)); + } + + private ClassLoaderContext(ClassLoader parent, List delegates) { + List loaders = new ArrayList(delegates); + loaders.remove(parent); + if (delegates.isEmpty()) { + classLoader = parent; + } else { + classLoader = new ClassLoaderDelegate(parent, loaders); + } + } + + /** + * Create a context that is visible to the parent classloader as well as the list of classloaders + * @param parent + * @param delegates + */ + public ClassLoaderContext(ClassLoader parent, ClassLoader... delegates) { + this(parent, Arrays.asList(delegates)); + } + + /** + * Create a context with the parent classloader and a list of service types that can be discovered + * by the {@link ServiceDiscovery} + * @param parent + * @param discovery + * @param serviceTypes + */ + public ClassLoaderContext(ClassLoader parent, ServiceDiscovery discovery, String... serviceTypes) { + this(parent, getClassLoaders(discovery, serviceTypes)); + } + + public T doPrivileged(PrivilegedAction action) { + ClassLoader tccl = Thread.currentThread().getContextClassLoader(); + if (tccl != classLoader) { + Thread.currentThread().setContextClassLoader(classLoader); + } + try { + return action.run(); + } finally { + if (tccl != classLoader) { + Thread.currentThread().setContextClassLoader(tccl); + } + } + } + + public T doPrivileged(PrivilegedExceptionAction action) throws PrivilegedActionException { + ClassLoader tccl = Thread.currentThread().getContextClassLoader(); + if (tccl != classLoader) { + Thread.currentThread().setContextClassLoader(classLoader); + } + try { + return action.run(); + } catch (Exception e) { + throw new PrivilegedActionException(e); + } finally { + if (tccl != classLoader) { + Thread.currentThread().setContextClassLoader(tccl); + } + } + } + + /** + * Set the thread context classloader (TCCL) to a classloader that delegates to a collection + * of classloaders + * @param parent The parent classloader + * @param delegates A list of classloaders to try + * @return The existing TCCL + */ + public static ClassLoader setContextClassLoader(ClassLoader parent, ClassLoader... delegates) { + ClassLoaderContext context = new ClassLoaderContext(parent, delegates); + return context.setContextClassLoader(); + } + + /** + * Set the context classloader so that it can access the list of service providers + * @param parent The parent classloader + * @param serviceNames A list of service provider names + * @return The old TCCL if a new one is set, otherwise null + */ + public static ClassLoader setContextClassLoader(ClassLoader parent, + ServiceDiscovery discovery, + String... serviceNames) { + ClassLoaderContext context = new ClassLoaderContext(parent, discovery, serviceNames); + return context.setContextClassLoader(); + } + + /** + * Set the context classloader so that it can access the list of service providers + * @param parent The parent classloader + * @param serviceNames A list of service provider names + * @return The old TCCL if a new one is set, otherwise null + */ + public static ClassLoader setContextClassLoader(ClassLoader parent, + ServiceDiscovery discovery, + Class... serviceTypes) { + ClassLoaderContext context = new ClassLoaderContext(parent, discovery, serviceTypes); + return context.setContextClassLoader(); + } + + public ClassLoader setContextClassLoader() { + ClassLoader tccl = Thread.currentThread().getContextClassLoader(); + if (tccl != classLoader) { + Thread.currentThread().setContextClassLoader(classLoader); + return tccl; + } else { + return null; + } + } + + private static ClassLoader getClassLoader(ServiceDiscovery discovery, String serviceProvider) { + try { + ServiceDeclaration sd = discovery.getServiceDeclaration(serviceProvider); + if (sd != null) { + try { + if (sd.loadClass() != null) { + return sd.loadClass().getClassLoader(); + } else { + return new ClassLoaderImpl(sd); + } + } catch (ClassNotFoundException e) { + return new ClassLoaderImpl(sd); + } + } + } catch (Exception e) { + // Ignore + } + return null; + } + + private static List getClassLoaders(ServiceDiscovery discovery, String... serviceNames) { + List loaders = new ArrayList(); + for (String sp : serviceNames) { + ClassLoader loader = getClassLoader(discovery, sp); + if (loader != null) { + if (!loaders.contains(loader)) { + loaders.add(loader); + } + } + } + ClassLoader tccl = discovery.getContextClassLoader(); + if (!loaders.contains(tccl)) { + loaders.add(tccl); + } + return loaders; + } + + private static ClassLoader getClassLoader(ServiceDiscovery discovery, Class serviceType) { + try { + ServiceDeclaration sd = discovery.getServiceDeclaration(serviceType); + if (sd != null) { + return sd.loadClass().getClassLoader(); + } + } catch (Exception e) { + // Ignore + } + return null; + } + + private static List getClassLoaders(ServiceDiscovery discovery, Class... serviceTypes) { + List loaders = new ArrayList(); + for (Class serviceType : serviceTypes) { + ClassLoader classLoader = getClassLoader(discovery, serviceType); + if (classLoader != null && !loaders.contains(classLoader)) { + loaders.add(classLoader); + } + } + ClassLoader tccl = discovery.getContextClassLoader(); + if (!loaders.contains(tccl)) { + loaders.add(tccl); + } + return loaders; + } + + public ClassLoader getClassLoader() { + return classLoader; + } + + private static class ClassLoaderImpl extends ClassLoader { + private final ServiceDeclaration sd; + + public ClassLoaderImpl(ServiceDeclaration sd) { + super(); + this.sd = sd; + } + + @Override + protected Class findClass(String name) throws ClassNotFoundException { + return sd.loadClass(name); + } + + @Override + protected URL findResource(String name) { + return sd.getResource(name); + } + + @Override + protected Enumeration findResources(String name) throws IOException { + return sd.getResources(name); + } + + } + +} -- cgit v1.2.3