Java tutorial
/* * Copyright 2002-2018 the original author or authors. * * Licensed 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 * * https://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.springframework.jms.config; import java.util.Collection; import java.util.Collections; import java.util.Map; import java.util.Set; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.atomic.AtomicInteger; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.beans.factory.BeanInitializationException; import org.springframework.beans.factory.DisposableBean; import org.springframework.beans.factory.InitializingBean; import org.springframework.context.ApplicationContext; import org.springframework.context.ApplicationContextAware; import org.springframework.context.ApplicationListener; import org.springframework.context.SmartLifecycle; import org.springframework.context.event.ContextRefreshedEvent; import org.springframework.jms.listener.MessageListenerContainer; import org.springframework.lang.Nullable; import org.springframework.util.Assert; /** * Creates the necessary {@link MessageListenerContainer} instances for the * registered {@linkplain JmsListenerEndpoint endpoints}. Also manages the * lifecycle of the listener containers, in particular within the lifecycle * of the application context. * * <p>Contrary to {@link MessageListenerContainer MessageListenerContainers} * created manually, listener containers managed by registry are not beans * in the application context and are not candidates for autowiring. * Use {@link #getListenerContainers()} if you need to access this registry's * listener containers for management purposes. If you need to access to a * specific message listener container, use {@link #getListenerContainer(String)} * with the id of the endpoint. * * @author Stephane Nicoll * @author Juergen Hoeller * @since 4.1 * @see JmsListenerEndpoint * @see MessageListenerContainer * @see JmsListenerContainerFactory */ public class JmsListenerEndpointRegistry implements DisposableBean, SmartLifecycle, ApplicationContextAware, ApplicationListener<ContextRefreshedEvent> { protected final Log logger = LogFactory.getLog(getClass()); private final Map<String, MessageListenerContainer> listenerContainers = new ConcurrentHashMap<>(); private int phase = DEFAULT_PHASE; @Nullable private ApplicationContext applicationContext; private boolean contextRefreshed; @Override public void setApplicationContext(ApplicationContext applicationContext) { this.applicationContext = applicationContext; } @Override public void onApplicationEvent(ContextRefreshedEvent event) { if (event.getApplicationContext() == this.applicationContext) { this.contextRefreshed = true; } } /** * Return the {@link MessageListenerContainer} with the specified id or * {@code null} if no such container exists. * @param id the id of the container * @return the container or {@code null} if no container with that id exists * @see JmsListenerEndpoint#getId() * @see #getListenerContainerIds() */ @Nullable public MessageListenerContainer getListenerContainer(String id) { Assert.notNull(id, "Container identifier must not be null"); return this.listenerContainers.get(id); } /** * Return the ids of the managed {@link MessageListenerContainer} instance(s). * @since 4.2.3 * @see #getListenerContainer(String) */ public Set<String> getListenerContainerIds() { return Collections.unmodifiableSet(this.listenerContainers.keySet()); } /** * Return the managed {@link MessageListenerContainer} instance(s). */ public Collection<MessageListenerContainer> getListenerContainers() { return Collections.unmodifiableCollection(this.listenerContainers.values()); } /** * Create a message listener container for the given {@link JmsListenerEndpoint}. * <p>This create the necessary infrastructure to honor that endpoint * with regards to its configuration. * <p>The {@code startImmediately} flag determines if the container should be * started immediately. * @param endpoint the endpoint to add * @param factory the listener factory to use * @param startImmediately start the container immediately if necessary * @see #getListenerContainers() * @see #getListenerContainer(String) */ public void registerListenerContainer(JmsListenerEndpoint endpoint, JmsListenerContainerFactory<?> factory, boolean startImmediately) { Assert.notNull(endpoint, "Endpoint must not be null"); Assert.notNull(factory, "Factory must not be null"); String id = endpoint.getId(); Assert.hasText(id, "Endpoint id must be set"); synchronized (this.listenerContainers) { if (this.listenerContainers.containsKey(id)) { throw new IllegalStateException("Another endpoint is already registered with id '" + id + "'"); } MessageListenerContainer container = createListenerContainer(endpoint, factory); this.listenerContainers.put(id, container); if (startImmediately) { startIfNecessary(container); } } } /** * Create a message listener container for the given {@link JmsListenerEndpoint}. * <p>This create the necessary infrastructure to honor that endpoint * with regards to its configuration. * @param endpoint the endpoint to add * @param factory the listener factory to use * @see #registerListenerContainer(JmsListenerEndpoint, JmsListenerContainerFactory, boolean) */ public void registerListenerContainer(JmsListenerEndpoint endpoint, JmsListenerContainerFactory<?> factory) { registerListenerContainer(endpoint, factory, false); } /** * Create and start a new container using the specified factory. */ protected MessageListenerContainer createListenerContainer(JmsListenerEndpoint endpoint, JmsListenerContainerFactory<?> factory) { MessageListenerContainer listenerContainer = factory.createListenerContainer(endpoint); if (listenerContainer instanceof InitializingBean) { try { ((InitializingBean) listenerContainer).afterPropertiesSet(); } catch (Exception ex) { throw new BeanInitializationException("Failed to initialize message listener container", ex); } } int containerPhase = listenerContainer.getPhase(); if (containerPhase < Integer.MAX_VALUE) { // a custom phase value if (this.phase < Integer.MAX_VALUE && this.phase != containerPhase) { throw new IllegalStateException("Encountered phase mismatch between container factory definitions: " + this.phase + " vs " + containerPhase); } this.phase = listenerContainer.getPhase(); } return listenerContainer; } // Delegating implementation of SmartLifecycle @Override public int getPhase() { return this.phase; } @Override public void start() { for (MessageListenerContainer listenerContainer : getListenerContainers()) { startIfNecessary(listenerContainer); } } @Override public void stop() { for (MessageListenerContainer listenerContainer : getListenerContainers()) { listenerContainer.stop(); } } @Override public void stop(Runnable callback) { Collection<MessageListenerContainer> listenerContainers = getListenerContainers(); AggregatingCallback aggregatingCallback = new AggregatingCallback(listenerContainers.size(), callback); for (MessageListenerContainer listenerContainer : listenerContainers) { listenerContainer.stop(aggregatingCallback); } } @Override public boolean isRunning() { for (MessageListenerContainer listenerContainer : getListenerContainers()) { if (listenerContainer.isRunning()) { return true; } } return false; } /** * Start the specified {@link MessageListenerContainer} if it should be started * on startup or when start is called explicitly after startup. * @see MessageListenerContainer#isAutoStartup() */ private void startIfNecessary(MessageListenerContainer listenerContainer) { if (this.contextRefreshed || listenerContainer.isAutoStartup()) { listenerContainer.start(); } } @Override public void destroy() { for (MessageListenerContainer listenerContainer : getListenerContainers()) { if (listenerContainer instanceof DisposableBean) { try { ((DisposableBean) listenerContainer).destroy(); } catch (Throwable ex) { logger.warn("Failed to destroy message listener container", ex); } } } } private static class AggregatingCallback implements Runnable { private final AtomicInteger count; private final Runnable finishCallback; public AggregatingCallback(int count, Runnable finishCallback) { this.count = new AtomicInteger(count); this.finishCallback = finishCallback; } @Override public void run() { if (this.count.decrementAndGet() == 0) { this.finishCallback.run(); } } } }