操作系统·Java实现阻塞队列的设计 （本质上是Java实现生产者消费者问题）·Condition条件变量

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


public class LinkedBlockingQueue<E> {
    private final int capacity;

    private Lock lock = new ReentrantLock();
    private LinkedList<E> queue;//缓冲区
    private int count; //缓冲区商品个数
    private Condition unfull = lock.newCondition();
    private Condition unEmpty = lock.newCondition();

    public LinkedBlockingQueue() throws InterruptedException {
        this(Integer.MAX_VALUE);
    }


    public LinkedBlockingQueue(int capacity) throws InterruptedException {
        this.capacity = capacity;
        queue = new LinkedList<E>();
    }


    public void put(E e) throws InterruptedException {
     
        try {
            while (count == capacity) {
                unfull.await();//阻塞队列已满，一直等待，直到有unfull
            }
            lock.lock(); //内层互斥夹紧
            queue.add(e);
            count++;
            lock.unlock();
            unfull.signal();
        } finally {
            
        }
    }

    public E take() throws InterruptedException {
        
        try {
            while (count == 0) {//队列为空，阻塞.一直等待指导有商品（unEmpty）
                unEmpty.await();
            }
            lock.lock();
            E e = queue.pop();
            count--;
            lock.unlock();
            unEmpty.signal();
            return e;
        } finally {
            
        }
    }

}