public class ReadThread implements Runnable{
  public Thread t;
  private String threadName;
  boolean suspended=false;
  public ReadThread(String threadName){
   this.threadName=threadName;
   System.out.println("Creating " + threadName );
  }
  public void run() {
   for(int i = 10; i > 0; i--) {
   System.out.println("Thread: " + threadName + ", " + i);
   // Let the thread sleep for a while.
   try {
    Thread.sleep(300);
    synchronized(this) {
     while(suspended) {
      wait();
     }
    }
   } catch (InterruptedException e) {
    System.out.println("Thread " + threadName + " interrupted.");
    e.printStackTrace();
   }
   System.out.println("Thread " + threadName + " exiting.");
   }
  }
  /**
   * 开始
   */
  public void start(){
   System.out.println("Starting " + threadName );
   if(t==null){
    t=new Thread(this, threadName);
    t.start();
   }
  }
  /**
   * 暂停
   */
   void suspend(){
   suspended = true;
  }
   /**
   * 继续
   */
   synchronized void resume(){
    suspended = false;
    notify();
   }
 }