ReentrantLock_Condition_实现生产者消费者的疑问点

 

 之前的疑问点： 为什么用while不用if,同时也存在图片中疑问

不懂结构还是很迷（待解答）

 

/**
 * 生产者消费者
 * 重入锁&条件
 * 条件 - Condition， 为Lock增加条件。当条件满足时，做什么事情，如加锁或解锁。如等待或唤醒
 */
package com.chenfan.base.server;

import lombok.extern.slf4j.Slf4j;

import java.util.LinkedList;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

@Slf4j
public class TestContainer02<E> {

    private final LinkedList<E> list = new LinkedList<>();
    private final int MAX = 2;

    private Lock lock = new ReentrantLock();
    private Condition producer = lock.newCondition();
    private Condition consumer = lock.newCondition();


    public void put(E e) {
        lock.lock();
        log.info("进入 put " + Thread.currentThread().getName() + " 入锁");
        try {
            while (list.size() == MAX) {
                log.info("lrwait" + Thread.currentThread().getName() + " 等待。。。");
                // 进入等待队列。释放锁标记。
                // 借助条件，进入的等待队列。
                producer.await();
            }
            log.info("lrkaishi" + Thread.currentThread().getName() + " put 。。。");
            Thread.sleep(1000);
            list.add(e);
            // 借助条件，唤醒所有的消费者。
            consumer.signalAll();
        } catch (InterruptedException e1) {
            e1.printStackTrace();
        } finally {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException ex) {
                ex.printStackTrace();
            }
            log.info("put 释放锁" + Thread.currentThread().getName());
            lock.unlock();
        }
    }

    public E get() {
        E e = null;

        lock.lock();
        //log.info("进入 get "+Thread.currentThread().getName() + " 入锁");
        try {
            while (list.size() == 0) {
                log.info(Thread.currentThread().getName() + " 等待。。。");
                // 借助条件，消费者进入等待队列
                consumer.await();
            }
            log.info(Thread.currentThread().getName() + " get 。。。");
            Thread.sleep(1000);

            e = list.removeFirst();
            // 借助条件，唤醒所有的生产者
            producer.signalAll();
        } catch (InterruptedException e1) {
            e1.printStackTrace();
        } finally {
            lock.unlock();
        }

        return e;
    }

    public static void main(String[] args) throws InterruptedException {
        final TestContainer02<String> c = new TestContainer02<>();
        for (int i = 0; i < 4; i++) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    for (int j = 0; j < 1; j++) {
                        log.info(c.get());
                    }
                }
            }, "consumer" + i).start();
        }

//        Thread.sleep(1000);
        for (int i = 0; i < 6; i++) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    for (int j = 0; j < 1; j++) {
                        c.put("container value " + j);
                    }
                }
            }, "producer" + i).start();
        }


    }

}