阻塞佇列BlockingQueue實現

import java.util.concurrent.BlockingQueue;

public class Consumer implements Runnable {
    /*
        BlockingQueue put(e) 和 take() 這兩個方法是帶阻塞的。
     */
    BlockingQueue<String> queue;

    public Consumer(BlockingQueue queue) {
        this.queue = queue;
    }

    @Override
    public
 
 void run() {
        try {
            String tmp = queue.take();
            System.out.println(Thread.currentThread().getName() + " have consumed a product from " + tmp);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

    }
}

import java.util.concurrent.BlockingQueue;
 


public class Producer implements Runnable {
    BlockingQueue<String> queue;

    public Producer(BlockingQueue queue) {
        this.queue = queue;
    }

    @Override
    public void run() {
        try {
            String tmp = Thread.currentThread().getName();
            System.out.println
 
(Thread.currentThread().getName() + " have made a product");
            queue.put(tmp);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;

public class Main {
    public static void main(String[] args) {
        BlockingQueue<String> queue = new LinkedBlockingQueue<String>(2);

        Producer producer = new Producer(queue);
        Consumer consumer = new Consumer(queue);
        for (int i = 0; i < 5; i++) {
            new Thread(producer, "Producer" + (i + 1)).start();

            new Thread(consumer, "Consumer" + (i + 1)).start();
        }

    }
}

輸出

Producer1 have made a product
Producer2 have made a product
Consumer2 have consumed a product from Producer1
Consumer1 have consumed a product from Producer2
Producer3 have made a product
Producer4 have made a product
Consumer4 have consumed a product from Producer3
Producer5 have made a product
Consumer5 have consumed a product from Producer4
Consumer3 have consumed a product from Producer5

synchronized關鍵字、wait、notify實現

import java.util.LinkedList;
import java.util.List;

public class Consumer implements Runnable {
    private List<String> buffer = new LinkedList<String>();
    private Integer capacity;

    public Consumer(List buffer, Integer capacity) {
        this.buffer = buffer;
        this.capacity = capacity;
    }

    @Override
    public void run() {
        synchronized (capacity){
            try {
                if (buffer.isEmpty())
                    capacity.wait();
                String tmp = buffer.remove(0);
                System.out.println(Thread.currentThread().getName() + " have consume a product from " + tmp);
                capacity.notifyAll();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

import java.util.LinkedList;
import java.util.List;

public class Producer implements Runnable {
    private List<String> buffer = new LinkedList<String>();
    private Integer capacity;

    public Producer(List buffer, Integer capacity) {
        this.buffer = buffer;
        this.capacity = capacity;
    }

    @Override
    public void run() {
        synchronized (capacity){
            try {
                if (buffer.size() >= capacity)
                    capacity.wait();
                buffer.add(Thread.currentThread().getName());
                System.out.println(Thread.currentThread().getName() + " have made a product");
                capacity.notifyAll();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

import java.util.LinkedList;
import java.util.List;

public class Main {

    public static void main(String[] args) {
        Integer capacity = 5;
        List<String> buffer = new LinkedList<String>();
        Producer producer = new Producer(buffer, capacity);
        Consumer consumer = new Consumer(buffer, capacity);
        for (int i = 1; i < 5; i++) {
            new Thread(producer,"Producer" + i).start();
            new Thread(consumer,"Consumer" + i).start();
        }
    }
}

輸出

Producer1 have made a product
Consumer1 have consume a product from Producer1
Producer2 have made a product
Producer3 have made a product
Producer4 have made a product
Consumer2 have consume a product from Producer2
Consumer4 have consume a product from Producer3
Consumer3 have consume a product from Producer4