Producer Consumer problem - Java Program

Q. Write a Java program using Synchronized Threads, which demonstrates Producer Consumer concept.

Answer:

Producer Consumer problem:
The producer-consumer problem is the classical concurrency of a multi process synchronization problem. It is also known as bound-buffer problem.

The problem describes two processes, the producer and the consumer, who share a common, fixed-size buffer used as a queue. The producer generates a piece of data, put it into the buffer and starts again.

ProducerConsumer.java

public class ProducerConsumer
{
      public static void main(String[] args)
      {
            Shop c = new Shop();
            Producer p1 = new Producer(c, 1);
            Consumer c1 = new Consumer(c, 1);
            p1.start();
            c1.start();
      }
}
class Shop
{
      private int materials;
      private boolean available = false;
      public synchronized int get()
      {
            while (available == false)
            {
                  try
                  {
                        wait();
                  }
                  catch (InterruptedException ie)
                  {
                  }
            }
            available = false;
            notifyAll();
            return materials;
      }
      public synchronized void put(int value)
      {
            while (available == true)
            {
                  try
                  {
                        wait();
                  }
                  catch (InterruptedException ie)
                  {
                        ie.printStackTrace();
                  }
            }
            materials = value;
            available = true;
            notifyAll();
      }
}
class Consumer extends Thread
{
      private Shop Shop;
      private int number;
      public Consumer(Shop c, int number)
      {
            Shop = c;
            this.number = number;
      }
      public void run()
      {
            int value = 0;
            for (int i = 0; i < 10; i++)
            {
                  value = Shop.get();
                  System.out.println("Consumed value " + this.number+ " got: " + value);
            }
      }
}
class Producer extends Thread
{
      private Shop Shop;
      private int number;

      public Producer(Shop c, int number)
      {
            Shop = c;
            this.number = number;
      }
      public void run()
      {
            for (int i = 0; i < 10; i++)
            {
                  Shop.put(i);
                  System.out.println("Produced value " + this.number+ " put: " + i);
                  try
                  {
                        sleep((int)(Math.random() * 100));
                  }
                  catch (InterruptedException ie)
                  {
                        ie.printStackTrace();
                  }
            }
      }
}


Output:

producer consumer
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