标签:多线程 blockingqueue arrayblockingqueue xmpp
在研究Smack的源代码的时候,我对它的连接Connection以及派生类XMPPConnection的关注是最多的,因为一个即时通信程序,它的网络模块必是它的核心。而我很在乎它是如何实现的。
在收发数据包的时候,我看到了队列的身影。BlockingQueue和ArrayBlockingQueue。所以,我觉得用到什么然后去查阅,去记录,这种方法是比较高效率的。
BlockingQueue是在Java的新的Concurrent包中的。
Reference:
http://www.cnblogs.com/jackyuj/archive/2010/11/24/1886553.html
在新增的Concurrent包中,BlockingQueue很好的解决了多线程中,如何高效安全“传输”数据的问题。通过这些高效并且线程安全的队列类,为我们快速搭建高质量的多线程程序带来极大的便利。本文详细介绍了BlockingQueue家庭中的所有成员,包括他们各自的功能以及常见使用场景。
import java.util.concurrent.BlockingQueue; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.LinkedBlockingQueue; /** * @author jackyuj */ public class BlockingQueueTest { public static void main(String[] args) throws InterruptedException { // 声明一个容量为10的缓存队列 BlockingQueue<String> queue = new LinkedBlockingQueue<String>(10); Producer producer1 = new Producer(queue); Producer producer2 = new Producer(queue); Producer producer3 = new Producer(queue); Consumer consumer = new Consumer(queue); // 借助Executors ExecutorService service = Executors.newCachedThreadPool(); // 启动线程 service.execute(producer1); service.execute(producer2); service.execute(producer3); service.execute(consumer); // 执行10s Thread.sleep(10 * 1000); producer1.stop(); producer2.stop(); producer3.stop(); Thread.sleep(2000); // 退出Executor service.shutdown(); } }
import java.util.Random; import java.util.concurrent.BlockingQueue; import java.util.concurrent.TimeUnit; /** * 消费者线程 * * @author jackyuj */ public class Consumer implements Runnable { public Consumer(BlockingQueue<String> queue) { this.queue = queue; } public void run() { System.out.println("启动消费者线程!"); Random r = new Random(); boolean isRunning = true; try { while (isRunning) { System.out.println("正从队列获取数据..."); String data = queue.poll(2, TimeUnit.SECONDS); if (null != data) { System.out.println("拿到数据:" + data); System.out.println("正在消费数据:" + data); Thread.sleep(r.nextInt(DEFAULT_RANGE_FOR_SLEEP)); } else { // 超过2s还没数据,认为所有生产线程都已经退出,自动退出消费线程。 isRunning = false; } } } catch (InterruptedException e) { e.printStackTrace(); Thread.currentThread().interrupt(); } finally { System.out.println("退出消费者线程!"); } } private BlockingQueue<String> queue; private static final int DEFAULT_RANGE_FOR_SLEEP = 1000; } import java.util.Random; import java.util.concurrent.BlockingQueue; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicInteger; /** * 生产者线程 * * @author jackyuj */ public class Producer implements Runnable { public Producer(BlockingQueue queue) { this.queue = queue; } public void run() { String data = null; Random r = new Random(); System.out.println("启动生产者线程!"); try { while (isRunning) { System.out.println("正在生产数据..."); Thread.sleep(r.nextInt(DEFAULT_RANGE_FOR_SLEEP)); data = "data:" + count.incrementAndGet(); System.out.println("将数据:" + data + "放入队列..."); if (!queue.offer(data, 2, TimeUnit.SECONDS)) { System.out.println("放入数据失败:" + data); } } } catch (InterruptedException e) { e.printStackTrace(); Thread.currentThread().interrupt(); } finally { System.out.println("退出生产者线程!"); } } public void stop() { isRunning = false; } private volatile boolean isRunning = true; private BlockingQueue queue; private static AtomicInteger count = new AtomicInteger(); private static final int DEFAULT_RANGE_FOR_SLEEP = 1000; }
package org.jivesoftware.smack; import java.util.concurrent.ArrayBlockingQueue; import java.util.concurrent.TimeUnit; import org.jivesoftware.smack.filter.PacketFilter; import org.jivesoftware.smack.packet.Packet; /** * Provides a mechanism to collect packets into a result queue that pass a * specified filter. The collector lets you perform blocking and polling * operations on the result queue. So, a PacketCollector is more suitable to * use than a {@link PacketListener} when you need to wait for a specific * result.<p> * * Each packet collector will queue up a configured number of packets for processing before * older packets are automatically dropped. The default number is retrieved by * {@link SmackConfiguration#getPacketCollectorSize()}. * * @see Connection#createPacketCollector(PacketFilter) * @author Matt Tucker */ public class PacketCollector { private PacketFilter packetFilter; private ArrayBlockingQueue<Packet> resultQueue; private Connection connection; private boolean cancelled = false; /** * Creates a new packet collector. If the packet filter is <tt>null</tt>, then * all packets will match this collector. * * @param conection the connection the collector is tied to. * @param packetFilter determines which packets will be returned by this collector. */ protected PacketCollector(Connection conection, PacketFilter packetFilter) { this(conection, packetFilter, SmackConfiguration.getPacketCollectorSize()); } /** * Creates a new packet collector. If the packet filter is <tt>null</tt>, then * all packets will match this collector. * * @param conection the connection the collector is tied to. * @param packetFilter determines which packets will be returned by this collector. * @param maxSize the maximum number of packets that will be stored in the collector. */ protected PacketCollector(Connection conection, PacketFilter packetFilter, int maxSize) { this.connection = conection; this.packetFilter = packetFilter; this.resultQueue = new ArrayBlockingQueue<Packet>(maxSize); } /** * Explicitly cancels the packet collector so that no more results are * queued up. Once a packet collector has been cancelled, it cannot be * re-enabled. Instead, a new packet collector must be created. */ public void cancel() { // If the packet collector has already been cancelled, do nothing. if (!cancelled) { cancelled = true; connection.removePacketCollector(this); } } /** * Returns the packet filter associated with this packet collector. The packet * filter is used to determine what packets are queued as results. * * @return the packet filter. */ public PacketFilter getPacketFilter() { return packetFilter; } /** * Polls to see if a packet is currently available and returns it, or * immediately returns <tt>null</tt> if no packets are currently in the * result queue. * * @return the next packet result, or <tt>null</tt> if there are no more * results. */ public Packet pollResult() { return resultQueue.poll(); } /** * Returns the next available packet. The method call will block (not return) * until a packet is available. * * @return the next available packet. */ public Packet nextResult() { try { return resultQueue.take(); } catch (InterruptedException e) { throw new RuntimeException(e); } } /** * Returns the next available packet. The method call will block (not return) * until a packet is available or the <tt>timeout</tt> has elapased. If the * timeout elapses without a result, <tt>null</tt> will be returned. * * @param timeout the amount of time to wait for the next packet (in milleseconds). * @return the next available packet. */ public Packet nextResult(long timeout) { try { return resultQueue.poll(timeout, TimeUnit.MILLISECONDS); } catch (InterruptedException e) { throw new RuntimeException(e); } } /** * Processes a packet to see if it meets the criteria for this packet collector. * If so, the packet is added to the result queue. * * @param packet the packet to process. */ protected void processPacket(Packet packet) { if (packet == null) { return; } if (packetFilter == null || packetFilter.accept(packet)) { while (!resultQueue.offer(packet)) { // Since we know the queue is full, this poll should never actually block. resultQueue.poll(); } } } }
标签:多线程 blockingqueue arrayblockingqueue xmpp
原文地址:http://blog.csdn.net/minimicall/article/details/39028045