Implement Producer Consumer Pattern using Semaphores

• Create shared Semaphore object , lock and unlock in consumer - producer  blocks by limiting thread accessible count to 1
• Output will be like produce 1 and consume 1 , produce 2 and consume 2 ...
• Producer.java
• public class Producer implements Runnable { private static List LIST; private static Semaphore semaphore; public Producer(List LISTv, Semaphore semaphoreV) { LIST = LISTv; semaphore = semaphoreV; } public void run() { produce(); } private static void produce() { try { int i = 1; while (true) { semaphore.acquire(); LIST.add(i); System.out.println(i + " Produced"); i++; semaphore.release(); if (i > 100) { break; } } } catch (Exception e) { e.printStackTrace(); } } }
• Consumer.java
• public class Consumer implements Runnable { private static List LIST; private static Semaphore semaphore; public Consumer(List LISTv, Semaphore semaphoreV) { LIST = LISTv; semaphore = semaphoreV; } public void run() { consume(); } private static void consume() { int index = 0; try { while (true) { semaphore.acquire(); index = LIST.size() - 1; System.out.println(LIST.get(index) + " Removed"); LIST.remove(index); semaphore.release(); } } catch (Exception e) { e.printStackTrace(); } } }
• App.java
• public class App { private static List LIST = new ArrayList(); private static Semaphore SEMAPHORE = new Semaphore(1, true); public static void main(String[] args) { Thread producer = new Thread(new Producer(LIST, SEMAPHORE)); Thread consumer = new Thread(new Consumer(LIST, SEMAPHORE)); producer.start(); consumer.start(); } }
• Output
• 1 Produced 1 Removed 2 Produced 2 Removed 3 Produced 3 Removed 4 Produced 4 Removed 5 Produced 5 Removed 6 Produced 6 Removed 7 Produced 7 Removed 8 Produced 8 Removed 9 Produced 9 Removed 10 Produced 10 Removed