Synchronized Queue with Producer and Consumer : Producer and consumer « Thread « Java Tutorial

1. Java Tutorial
2. Thread
3. Producer and consumer

public class ThreadTester {
  public static void main(String[] args) {
    SynchronizedQueue<String> queue = new SynchronizedQueue<String>(10);
    final int GREETING_COUNT = 100;
    Runnable run1 = new Producer("Hello, World!", queue, GREETING_COUNT);
    Runnable run2 = new Producer("Goodbye, World!", queue, GREETING_COUNT);
    Runnable run3 = new Consumer(queue, 2 * GREETING_COUNT);

    Thread thread1 = new Thread(run1);
    Thread thread2 = new Thread(run2);
    Thread thread3 = new Thread(run3);

    thread1.start();
    thread2.start();
    thread3.start();
  }
}

class Producer implements Runnable {
  private String greeting;
  private SynchronizedQueue<String> queue;

  private int greetingCount;

  public Producer(String aGreeting, SynchronizedQueue<String> aQueue, int count) {
    greeting = aGreeting;
    queue = aQueue;
    greetingCount = count;
  }

  public void run() {
    try {
      int i = 1;
      while (i <= greetingCount) {
        queue.add(i + ": " + greeting);
        i++;
        Thread.sleep(2000);
      }
    } catch (InterruptedException exception) {
    }
  }

}

class Consumer implements Runnable {

  private SynchronizedQueue<String> queue;

  private int greetingCount;

  public Consumer(SynchronizedQueue<String> aQueue, int count) {
    queue = aQueue;
    greetingCount = count;
  }

  public void run() {
    try {
      int i = 1;
      while (i <= greetingCount) {
        String greeting = queue.remove();
        System.out.println(greeting);
        i++;
        Thread.sleep(3000);
      }
    } catch (InterruptedException exception) {
    }
  }

}

class SynchronizedQueue<V> {

  private Object[] elements;

  private int head;

  private int tail;

  private int size;

  public SynchronizedQueue(int capacity) {
    elements = new Object[capacity];
    head = 0;
    tail = 0;
    size = 0;
  }

  public synchronized V remove() throws InterruptedException {
    while (size == 0)
      wait();
    V r = (V) elements[head];
    head++;
    size--;
    if (head == elements.length)
      head = 0;
    notifyAll();
    return r;
  }

  public synchronized void add(V newValue) throws InterruptedException {
    while (size == elements.length)
      wait();
    elements[tail] = newValue;
    tail++;
    size++;
    if (tail == elements.length)
      tail = 0;
    notifyAll();
  }

}