| /** |
| * 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.atlas.plugin.classloader; |
| |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.io.IOException; |
| import java.net.URISyntaxException; |
| import java.net.URL; |
| import java.net.URLClassLoader; |
| import java.security.AccessController; |
| import java.security.PrivilegedAction; |
| import java.security.PrivilegedActionException; |
| import java.security.PrivilegedExceptionAction; |
| import java.util.Enumeration; |
| |
| /** |
| * AtlasPluginClassLoader to use plugin classpath first, before component classpath. |
| */ |
| public final class AtlasPluginClassLoader extends URLClassLoader { |
| private static final Logger LOG = LoggerFactory.getLogger(AtlasPluginClassLoader.class); |
| |
| private static volatile AtlasPluginClassLoader me = null; |
| |
| private final ThreadLocal<ClassLoader> preActivateClassLoader = new ThreadLocal<>(); |
| |
| private final MyClassLoader componentClassLoader; |
| |
| private AtlasPluginClassLoader(String pluginType, Class<?> pluginClass) throws URISyntaxException { |
| this(AtlasPluginClassLoaderUtil.getPluginImplLibPath(pluginType, pluginClass)); |
| } |
| |
| //visible for testing |
| AtlasPluginClassLoader(String libraryPath) { |
| super(AtlasPluginClassLoaderUtil.getFilesInDirectories(new String[]{libraryPath}), null); |
| |
| componentClassLoader = AccessController.doPrivileged(new PrivilegedAction<MyClassLoader>() { |
| public MyClassLoader run() { |
| return new MyClassLoader(Thread.currentThread().getContextClassLoader()); |
| } |
| }); |
| } |
| |
| public static AtlasPluginClassLoader getInstance(final String pluginType, final Class<?> pluginClass) throws PrivilegedActionException { |
| AtlasPluginClassLoader ret = me; |
| if (ret == null) { |
| synchronized (AtlasPluginClassLoader.class) { |
| ret = me; |
| if (ret == null) { |
| me = AccessController.doPrivileged(new PrivilegedExceptionAction<AtlasPluginClassLoader>() { |
| public AtlasPluginClassLoader run() throws URISyntaxException { |
| return new AtlasPluginClassLoader(pluginType, pluginClass); |
| } |
| }); |
| ret = me; |
| } |
| } |
| } |
| return ret; |
| } |
| |
| @Override |
| public Class<?> findClass(String name) throws ClassNotFoundException { |
| if (LOG.isTraceEnabled()) { |
| LOG.trace("==> AtlasPluginClassLoader.findClass({})", name); |
| } |
| |
| Class<?> ret = null; |
| |
| try { |
| // first try to find the class in pluginClassloader |
| if (LOG.isTraceEnabled()) { |
| LOG.trace("AtlasPluginClassLoader.findClass({}): calling pluginClassLoader.findClass()", name); |
| } |
| |
| ret = super.findClass(name); |
| } catch (Throwable e) { |
| // on failure to find in pluginClassLoader, try to find in componentClassLoader |
| MyClassLoader savedClassLoader = getComponentClassLoader(); |
| |
| if (savedClassLoader != null) { |
| if (LOG.isTraceEnabled()) { |
| LOG.trace("AtlasPluginClassLoader.findClass({}): calling componentClassLoader.findClass()", name); |
| } |
| |
| ret = savedClassLoader.findClass(name); |
| } |
| } |
| |
| if (LOG.isTraceEnabled()) { |
| LOG.trace("<== AtlasPluginClassLoader.findClass({}): {}", name, ret); |
| } |
| |
| return ret; |
| } |
| |
| @Override |
| public Class<?> loadClass(String name) throws ClassNotFoundException { |
| if (LOG.isTraceEnabled()) { |
| LOG.trace("==> AtlasPluginClassLoader.loadClass({})", name); |
| } |
| |
| Class<?> ret = null; |
| |
| try { |
| // first try to load the class from pluginClassloader |
| if (LOG.isTraceEnabled()) { |
| LOG.trace("AtlasPluginClassLoader.loadClass({}): calling pluginClassLoader.loadClass()", name); |
| } |
| |
| ret = super.loadClass(name); |
| } catch (Throwable e) { |
| // on failure to load from pluginClassLoader, try to load from componentClassLoader |
| MyClassLoader savedClassLoader = getComponentClassLoader(); |
| |
| if (savedClassLoader != null) { |
| if (LOG.isTraceEnabled()) { |
| LOG.trace("AtlasPluginClassLoader.loadClass({}): calling componentClassLoader.loadClass()", name); |
| } |
| |
| ret = savedClassLoader.loadClass(name); |
| } |
| } |
| |
| if (LOG.isTraceEnabled()) { |
| LOG.trace("<== AtlasPluginClassLoader.loadClass({}): {}", name, ret); |
| } |
| |
| return ret; |
| } |
| |
| @Override |
| public URL findResource(String name) { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("==> AtlasPluginClassLoader.findResource({}) ", name); |
| } |
| |
| // first try to find the resource from pluginClassloader |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("AtlasPluginClassLoader.findResource({}): calling pluginClassLoader.findResource()", name); |
| } |
| |
| URL ret = super.findResource(name); |
| |
| if (ret == null) { |
| MyClassLoader savedClassLoader = getComponentClassLoader(); |
| |
| if (savedClassLoader != null) { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("AtlasPluginClassLoader.findResource({}): calling componentClassLoader.getResource()", name); |
| } |
| |
| ret = savedClassLoader.getResource(name); |
| } |
| } |
| |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("<== AtlasPluginClassLoader.findResource({}): {}", name, ret); |
| } |
| |
| return ret; |
| } |
| |
| @Override |
| public Enumeration<URL> findResources(String name) throws IOException { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("==> AtlasPluginClassLoader.findResources({})", name); |
| } |
| |
| Enumeration<URL> ret = null; |
| |
| Enumeration<URL> resourcesInPluginClsLoader = findResourcesUsingPluginClassLoader(name); |
| Enumeration<URL> resourcesInComponentClsLoader = findResourcesUsingComponentClassLoader(name); |
| |
| if (resourcesInPluginClsLoader != null && resourcesInComponentClsLoader != null) { |
| ret = new MergeEnumeration(resourcesInPluginClsLoader, resourcesInComponentClsLoader); |
| } else if (resourcesInPluginClsLoader != null) { |
| ret = resourcesInPluginClsLoader; |
| } else { |
| ret = resourcesInComponentClsLoader; |
| } |
| |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("<== AtlasPluginClassLoader.findResources({}): {}", name, ret); |
| } |
| |
| return ret; |
| } |
| |
| public void activate() { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("==> AtlasPluginClassLoader.activate()"); |
| } |
| |
| preActivateClassLoader.set(Thread.currentThread().getContextClassLoader()); |
| |
| Thread.currentThread().setContextClassLoader(this); |
| |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("<== AtlasPluginClassLoader.activate()"); |
| } |
| } |
| |
| public void deactivate() { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("==> AtlasPluginClassLoader.deactivate()"); |
| } |
| |
| ClassLoader classLoader = preActivateClassLoader.get(); |
| |
| if (classLoader != null) { |
| preActivateClassLoader.remove(); |
| } else { |
| MyClassLoader savedClassLoader = getComponentClassLoader(); |
| if (savedClassLoader != null && savedClassLoader.getParent() != null) { |
| classLoader = savedClassLoader.getParent(); |
| } |
| } |
| |
| if (classLoader != null) { |
| Thread.currentThread().setContextClassLoader(classLoader); |
| } else { |
| LOG.warn("AtlasPluginClassLoader.deactivate() was not successful.Couldn't not get the saved " |
| + "componentClassLoader..."); |
| } |
| |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("<== AtlasPluginClassLoader.deactivate()"); |
| } |
| } |
| |
| private MyClassLoader getComponentClassLoader() { |
| return componentClassLoader; |
| } |
| |
| private Enumeration<URL> findResourcesUsingPluginClassLoader(String name) { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("==> AtlasPluginClassLoader.findResourcesUsingPluginClassLoader({})", name); |
| } |
| |
| Enumeration<URL> ret = null; |
| |
| try { |
| ret = super.findResources(name); |
| } catch (Throwable excp) { |
| // Ignore exceptions |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("AtlasPluginClassLoader.findResourcesUsingPluginClassLoader({}): resource not found in plugin", name, excp); |
| } |
| } |
| |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("<== AtlasPluginClassLoader.findResourcesUsingPluginClassLoader({}): {}", name, ret); |
| } |
| |
| return ret; |
| } |
| |
| private Enumeration<URL> findResourcesUsingComponentClassLoader(String name) { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("==> AtlasPluginClassLoader.findResourcesUsingComponentClassLoader({})", name); |
| } |
| |
| Enumeration<URL> ret = null; |
| |
| try { |
| MyClassLoader savedClassLoader = getComponentClassLoader(); |
| |
| if (savedClassLoader != null) { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("AtlasPluginClassLoader.findResourcesUsingComponentClassLoader({}): calling componentClassLoader.getResources()", name); |
| } |
| |
| ret = savedClassLoader.getResources(name); |
| } |
| |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("<== AtlasPluginClassLoader.findResourcesUsingComponentClassLoader({}): {}", name, ret); |
| } |
| } catch (Throwable t) { |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("AtlasPluginClassLoader.findResourcesUsingComponentClassLoader({}): class not found in componentClassLoader.", name, t); |
| } |
| } |
| |
| return ret; |
| } |
| |
| static class MergeEnumeration implements Enumeration<URL> { //NOPMD |
| private Enumeration<URL> e1 = null; |
| private Enumeration<URL> e2 = null; |
| |
| public MergeEnumeration(Enumeration<URL> e1, Enumeration<URL> e2) { |
| this.e1 = e1; |
| this.e2 = e2; |
| } |
| |
| @Override |
| public boolean hasMoreElements() { |
| return ((e1 != null && e1.hasMoreElements()) || (e2 != null && e2.hasMoreElements())); |
| } |
| |
| @Override |
| public URL nextElement() { |
| URL ret = null; |
| |
| if (e1 != null && e1.hasMoreElements()) { |
| ret = e1.nextElement(); |
| } else if (e2 != null && e2.hasMoreElements()) { |
| ret = e2.nextElement(); |
| } |
| |
| return ret; |
| } |
| } |
| |
| static class MyClassLoader extends ClassLoader { |
| public MyClassLoader(ClassLoader realClassLoader) { |
| super(realClassLoader); |
| } |
| |
| @Override |
| public Class<?> findClass(String name) throws ClassNotFoundException { //NOPMD |
| return super.findClass(name); |
| } |
| } |
| } |