Java tutorial
// Copyright (c) 2007-Present Pivotal Software, Inc. All rights reserved. // // This software, the RabbitMQ Java client library, is triple-licensed under the // Mozilla Public License 1.1 ("MPL"), the GNU General Public License version 2 // ("GPL") and the Apache License version 2 ("ASL"). For the MPL, please see // LICENSE-MPL-RabbitMQ. For the GPL, please see LICENSE-GPL2. For the ASL, // please see LICENSE-APACHE2. // // This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, // either express or implied. See the LICENSE file for specific language governing // rights and limitations of this software. // // If you have any questions regarding licensing, please contact us at // info@rabbitmq.com. package com.rabbitmq.client.impl; import java.util.ArrayList; import java.util.List; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.ThreadFactory; import com.rabbitmq.client.Channel; final public class ConsumerWorkService { private static final int MAX_RUNNABLE_BLOCK_SIZE = 16; private static final int DEFAULT_NUM_THREADS = Runtime.getRuntime().availableProcessors() * 2; private final ExecutorService executor; private final boolean privateExecutor; private final WorkPool<Channel, Runnable> workPool; private final int shutdownTimeout; public ConsumerWorkService(ExecutorService executor, ThreadFactory threadFactory, int queueingTimeout, int shutdownTimeout) { this.privateExecutor = (executor == null); this.executor = (executor == null) ? Executors.newFixedThreadPool(DEFAULT_NUM_THREADS, threadFactory) : executor; this.workPool = new WorkPool<>(queueingTimeout); this.shutdownTimeout = shutdownTimeout; } public ConsumerWorkService(ExecutorService executor, ThreadFactory threadFactory, int shutdownTimeout) { this(executor, threadFactory, -1, shutdownTimeout); } public int getShutdownTimeout() { return shutdownTimeout; } /** * Stop executing all consumer work */ public void shutdown() { this.workPool.unregisterAllKeys(); if (privateExecutor) this.executor.shutdown(); } /** * Stop executing all consumer work for a particular channel * @param channel to stop consumer work for */ public void stopWork(Channel channel) { this.workPool.unregisterKey(channel); } public void registerKey(Channel channel) { this.workPool.registerKey(channel); } public void setUnlimited(Channel channel, boolean unlimited) { if (unlimited) { this.workPool.unlimit(channel); } else { this.workPool.limit(channel); } } public void addWork(Channel channel, Runnable runnable) { if (this.workPool.addWorkItem(channel, runnable)) { this.executor.execute(new WorkPoolRunnable()); } } /** * @return true if executor used by this work service is managed * by it and wasn't provided by the user */ public boolean usesPrivateExecutor() { return privateExecutor; } private final class WorkPoolRunnable implements Runnable { @Override public void run() { int size = MAX_RUNNABLE_BLOCK_SIZE; List<Runnable> block = new ArrayList<Runnable>(size); try { Channel key = ConsumerWorkService.this.workPool.nextWorkBlock(block, size); if (key == null) return; // nothing ready to run try { for (Runnable runnable : block) { runnable.run(); } } finally { if (ConsumerWorkService.this.workPool.finishWorkBlock(key)) { ConsumerWorkService.this.executor.execute(new WorkPoolRunnable()); } } } catch (RuntimeException e) { Thread.currentThread().interrupt(); } } } }