利用Syschronized和wait,notify实现线程安全的阻塞队列

class MQueue {
    
    private List<String> list = new ArrayList<String>();
    
    private int maxSize;
    
    private Object lock = new Object();
    
    public MQueue(int maxSize){
        this.maxSize=maxSize;
        System.out.println("线程"+Thread.currentThread().getName()+"已初始化长度为"+this.maxSize+"的队列");
    }
    
    public void put(String element){
        synchronized (lock) {
            if(this.list.size()==this.maxSize){
                try {
                    System.out.println("线程"+Thread.currentThread().getName()+"当前队列已满put等待...");
                    lock.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            this.list.add(element);
            System.out.println("线程"+Thread.currentThread().getName()+"向队列中加入元素:"+element);
            lock.notifyAll(); //通知可以取数据
        }
    }
    
    public String take(){
        synchronized (lock) {
            if(this.list.size()==0){
                try {
                    System.out.println("线程"+Thread.currentThread().getName()+"队列为空take等待...");
                    lock.wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            String result = list.get(0);
            list.remove(0);
            System.out.println("线程"+Thread.currentThread().getName()+"获取数据:"+result);
            lock.notifyAll(); //通知可以加入数据
            return result;
        }
    }
}

public class DemoThread20 {
    public static void main(String[] args) {
        final MQueue q = new MQueue(5);
        
        new Thread(new Runnable() {
            @Override
            public void run() {
                q.put("1");
                q.put("2");
                q.put("3");
                q.put("4");
                q.put("5");
                q.put("6");
            }
        },"t1").start();
        
        new Thread(new Runnable() {
            @Override
            public void run() {
                q.put("11");
                q.put("21");
                q.put("31");
                q.put("41");
                q.put("51");
                q.put("61");
            }
        },"t2").start();
        
        new Thread(new Runnable() {
            @Override
            public void run() {
                q.take();
                q.take();
                q.take();
                q.take();
                q.take();
            }
        },"t3").start();
        
        new Thread(new Runnable() {
            @Override
            public void run() {
                q.take();
                q.take();
                q.take();
                q.take();
                q.take();
            }
        },"t4").start();
    }
}