1. Exchanger

用於執行緒之間的資料交換

//生產者生產出固定的數量後與消費者的產品容器進行交換
class Producer implements Runnable{
    private Queue<String> products;
    private Exchanger<Queue> exchanger;
    private int maxNum;
    private int id;
    private static int allId;

    public Producer(Queue<String> products,Exchanger exchanger,int
 
 maxNum) {
        this.products = products;
        this.exchanger = exchanger;
        this.maxNum = maxNum;
        this.id = allId++;
    }

    @Override
    public void run() {
        try {
            while (!Thread.interrupted()){
                synchronized (Producer.class){
                    
 
while (products.size() >= this.maxNum){
                        this.products = exchanger.exchange(products);
                    }
                }
                System.out.println("生產者" + this.id + "號開始生產");
                TimeUnit.MILLISECONDS.sleep(new Random().nextInt(1000) + 500);
                products.offer(
 
"產品-----" + "生產者" + this.id + "號");
                System.out.println("生產者" + this.id + "生產完畢");
            }
        }
        catch (Exception e){
            e.printStackTrace();
        }
    }
}

//消費者的產品佇列為空的時候與生產者的產品佇列進行交換
class Consumer implements Runnable{
    private Queue<String> products;
    private Exchanger<Queue> exchanger;
    private int id;
    private static int allId;

    public Consumer(Queue<String> products,Exchanger exchanger) {
        this.products = products;
        this.exchanger = exchanger;
        this.id = allId++;
    }

    @Override
    public void run() {
        while (!Thread.interrupted()){
            try {
                //保證只有一個執行緒會進行佇列的交換
                synchronized (Consumer.class){
                    while (products.isEmpty()){
                        exchanger.exchange(products);
                    }
                    System.out.println("消費者" + this.id + "開始消費" + products.poll());
                }

                TimeUnit.MILLISECONDS.sleep(new Random().nextInt(1000) + 500);
                System.out.println("消費者" + this.id + "消費結束");
            }
            catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}

//main
class Main{
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        ExecutorService executorService = Executors.newFixedThreadPool(4);
        Queue<String> producerList = new LinkedList<>();
        Queue<String> consumerList = new LinkedList<>();
        Exchanger exchanger = new Exchanger();

        for(int i = 0;i < 2;i++){
            executorService.submit(new Producer(producerList,exchanger,5));
            executorService.submit(new Consumer(consumerList,exchanger));
        }

    }
}