Publisher list Subscribe With ReentrantLock - Java Thread

Java examples for Thread:Lock

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Description

Publisher list Subscribe With ReentrantLock

Demo Code



import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;

public class PubSubWithReentrant {
    private List<String> queue = new ArrayList<>();
    ReentrantLock mutex = new ReentrantLock(true);// fair lock

    public static void main(String[] args) throws InterruptedException {
    PubSubWithReentrant pubSub = new PubSubWithReentrant();
    Condition reader = pubSub.mutex.newCondition();
    Condition writer = pubSub.mutex.newCondition();

    ExecutorService executor = Executors.newFixedThreadPool(5);
    executor.execute(() -> pubSub.publish(reader, writer));
    executor.execute(() -> pubSub.subscribe(reader, writer));

    executor.shutdown();//from ww w.  j  av a  2  s .c om
}

    private void publish(Condition reader, Condition writer) {
        String message;
        for (int i = 0; i < 10; i++) {

            mutex.lock();

            while (queue.size() == 3) {
                // wait
                try {
                    writer.await();
                } catch (InterruptedException e) {
                }
            }
            message = UUID.randomUUID().toString();
            System.out.println(Thread.currentThread().getName()
                    + ": Publish......" + message);
            queue.add(message);
            // notify sub
            reader.signal();

            mutex.unlock();
        }
    }

    private void subscribe(Condition reader, Condition writer) {
        for (int i = 0; i < 10; i++) {

            mutex.lock();

            while (queue.size() == 0) {
                // wait
                try {
                    reader.await();
                } catch (InterruptedException e) {
                }
            }
            System.out.println(Thread.currentThread().getName()
                    + ": Subscribe......" + queue.remove(0));
            // notify pub
            writer.signal();

            mutex.unlock();
        }
    }
}

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