// 生产者
class Producer implements Runnable {
  private final BlockingQueue<Integer> queue;

  public Producer(BlockingQueue queue) {
    this.queue = queue;
  }

  @Override
  public void run() {
    while (true) {
      try {
        queue.put(produce());
        System.out.println(Thread.currentThread().getName() + " put a message, total = " + queue.size());
        Thread.sleep(3000);
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
    }
  }

  private int produce() {
    int x = (int) (Math.random() * 10);
    System.out.println(Thread.currentThread().getName() + " put: " + x);
    return x;
  }
}