Implement a Pub-Sub model - Java Thread

Java examples for Thread:Producer Consumer

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Introduction

Implement a Pub-Sub model using following criteria:

  • There is a queue (i.e list) with a certain capacity (10)
  • M number of publisher and N number of subscriber sharing the queue.
  • Publisher has to wait if queue capacity is full
  • Subscriber will wait if queue is empty
  • Use thread signaling (wait, notify / notifyAll)

Demo Code



import java.util.ArrayList;
import java.util.List;

public class Main {
    int nextInitial = 0;
    private int initialCapacity = 10;
    private List<Integer> list = new ArrayList<>(initialCapacity);

    public static void main(String[] args) {
    Main threadSignaling = new Main();

    Thread publisher1 = new Thread(() -> threadSignaling.publisher());
    publisher1.start();/*from ww  w .jav a  2s  .  c  o  m*/

    Thread subscriber1 = new Thread(() -> threadSignaling.subscriber());
    subscriber1.start();

}

    public void subscriber() {

        for (int i = 0; i < initialCapacity; i++) {
            synchronized (this) {
                try {
                    while (list.size() == 0) {
                        this.wait();
                    }
                    System.out.println(Thread.currentThread().getName()
                            + " " + nextInitial + ". Message subscribed..."
                            + list.get(0));
                    list.remove(0);
                    this.notifyAll();
                } catch (InterruptedException e) {
                }
            }
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    public void publisher() {

        for (int i = 0; i < initialCapacity; i++) {
            synchronized (this) {
                try {
                    while (list.size() == 3) {
                        this.wait();
                    }
                    list.add(nextInitial);
                    System.out.println(Thread.currentThread().getName()
                            + " " + nextInitial + ". Message published..."
                            + nextInitial);
                    nextInitial++;
                    this.notifyAll();
                } catch (InterruptedException e) {
                }
            }
            try {
                Thread.sleep(500);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

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