Java7新特性（四）并发 6 TransferQueue对象

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本文主要根据《Java程序员修炼之道》整理的代码笔记片段

TransferQueue对象如果接收线程处于等待状态，transfer（）马上把工作项传给它，否则就会阻塞直到取走工作项 [高效]

即正在处理的工作项的线程在交付当前工作之前（被取走之前），不开始其他工作项的处理。

public abstract class MicroBlogThread extends Thread {  protected final TransferQueue<Update> updates;  protected String text = "";  protected final int pauseTime;  private boolean shutdown = false;  public MicroBlogThread(TransferQueue<Update> lbq_, int pause_) {    updates = lbq_;    pauseTime = pause_;  }  public synchronized void shutdown() {    shutdown = true;  }  @Override  public void run() {    while (!shutdown) {      doAction();      try {        Thread.sleep(pauseTime);      } catch (InterruptedException e) {        shutdown = true;      }    }  }  public abstract void doAction();}

public class MicroBlogThreadMain {  public static void main(String[] a) {    final Update.Builder ub = new Update.Builder();    final TransferQueue<Update> lbq = new LinkedTransferQueue<>();    //如果接收线程处于等待状态，transfer（）马上把工作项传给它，否则就会阻塞直到取走工作项  [高效]    MicroBlogThread t1 = new MicroBlogThread(lbq, 10) {      public void doAction() {        text = text + "X";        Update u = ub.author(new Author("Tallulah")).updateText(text).build();        boolean handed = false;        try {          handed = updates.offer(u, 100, TimeUnit.MILLISECONDS);        } catch (InterruptedException e) {        }        if (!handed)          System.out              .println("Unable to handoff Update to Queue due to timeout");      }    };    MicroBlogThread t2 = new MicroBlogThread(lbq, 1000) {      public void doAction() {        @SuppressWarnings("unused")Update u = null;        try {          u = updates.take();        } catch (InterruptedException e) {          return;        }      }    };    t1.start();    t2.start();  }}

如果采用LinkedBlockingQueue 必须设置大小，不然相连线程池塞入过快，会内存溢出