7 线程通信之生产者与消费者传统版

public class ProdConsumer_BlockQueueDemo {

    private volatile int num;
    Lock lock = new ReentrantLock();
    Condition condition = lock.newCondition();

    public void increment(){
       lock.lock();
       try{
          // 不能用if 
           while (num != 0){
               // 等待不能生产
               condition.await();
           }
           num++;
           System.out.println(Thread.currentThread().getName()+" "+num);
           condition.signalAll();
       }catch (Exception ignored){
       }finally {
           lock.unlock();
       }
    }

    public void decrement(){
        lock.lock();
        try{
          // 不能用if
            while (num == 0){
                // 等待不能消费
                condition.await();
            }
            num--;
            System.out.println(Thread.currentThread().getName()+" "+num);
            condition.signalAll();
        }catch (Exception ignored){
        }finally {
            lock.unlock();
        }
    }

    public static void main(String[] args) {
        ProdConsumer_BlockQueueDemo prodConsumer_blockQueueDemo = new ProdConsumer_BlockQueueDemo();

            new Thread(()->{
                for (int i = 0; i < 5; i++) {
                    prodConsumer_blockQueueDemo.increment();
                }
            },"AAA").start();
            new Thread(()->{
                for (int i = 0; i < 5; i++) {
                    prodConsumer_blockQueueDemo.decrement();
                }
            },"BBB").start();

            new Thread(()->{
                for (int i = 0; i < 5; i++) {
                    prodConsumer_blockQueueDemo.increment();
                }
            },"CCC").start();
            new Thread(()->{
                for (int i = 0; i < 5; i++) {
                    prodConsumer_blockQueueDemo.decrement();
                }
            },"DDD").start();


    }
}