| /* |
| * 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.nifi.nar; |
| |
| import java.io.Closeable; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * |
| */ |
| public class NarCloseable implements Closeable { |
| |
| private static final Logger logger = LoggerFactory.getLogger(NarCloseable.class); |
| |
| public static NarCloseable withNarLoader() { |
| final ClassLoader current = Thread.currentThread().getContextClassLoader(); |
| Thread.currentThread().setContextClassLoader(NarThreadContextClassLoader.getInstance()); |
| return new NarCloseable(current); |
| } |
| |
| /** |
| * Sets the current thread context class loader to the specific appropriate class loader for the given |
| * component. If the component requires per-instance class loading then the class loader will be the |
| * specific class loader for instance with the given identifier, otherwise the class loader will be |
| * the NARClassLoader. |
| * |
| * @param componentClass the component class |
| * @param componentIdentifier the identifier of the component |
| * @return NarCloseable with the current thread context classloader jailed to the Nar |
| * or instance class loader of the component |
| */ |
| public static NarCloseable withComponentNarLoader(final Class componentClass, final String componentIdentifier) { |
| final ClassLoader current = Thread.currentThread().getContextClassLoader(); |
| |
| ClassLoader componentClassLoader = ExtensionManager.getInstanceClassLoader(componentIdentifier); |
| if (componentClassLoader == null) { |
| componentClassLoader = componentClass.getClassLoader(); |
| } |
| |
| Thread.currentThread().setContextClassLoader(componentClassLoader); |
| return new NarCloseable(current); |
| } |
| |
| /** |
| * Sets the current thread context class loader to the provided class loader, and returns a NarCloseable that will |
| * return the current thread context class loader to it's previous state. |
| * |
| * @param componentNarLoader the class loader to set as the current thread context class loader |
| * |
| * @return NarCloseable that will return the current thread context class loader to its previous state |
| */ |
| public static NarCloseable withComponentNarLoader(final ClassLoader componentNarLoader) { |
| final ClassLoader current = Thread.currentThread().getContextClassLoader(); |
| Thread.currentThread().setContextClassLoader(componentNarLoader); |
| return new NarCloseable(current); |
| } |
| |
| /** |
| * Creates a Closeable object that can be used to to switch to current class |
| * loader to the framework class loader and will automatically set the |
| * ClassLoader back to the previous class loader when closed |
| * |
| * @return a NarCloseable |
| */ |
| public static NarCloseable withFrameworkNar() { |
| final ClassLoader frameworkClassLoader; |
| try { |
| frameworkClassLoader = NarClassLoaders.getInstance().getFrameworkBundle().getClassLoader(); |
| } catch (final Exception e) { |
| // This should never happen in a running instance, but it will occur in unit tests |
| logger.error("Unable to access Framework ClassLoader due to " + e + ". Will continue without changing ClassLoaders."); |
| if (logger.isDebugEnabled()) { |
| logger.error("", e); |
| } |
| |
| return new NarCloseable(null); |
| } |
| |
| final ClassLoader current = Thread.currentThread().getContextClassLoader(); |
| Thread.currentThread().setContextClassLoader(frameworkClassLoader); |
| return new NarCloseable(current); |
| } |
| |
| private final ClassLoader toSet; |
| |
| private NarCloseable(final ClassLoader toSet) { |
| this.toSet = toSet; |
| } |
| |
| @Override |
| public void close() { |
| if (toSet != null) { |
| Thread.currentThread().setContextClassLoader(toSet); |
| } |
| } |
| } |