Scalable Human Blog

Hello, fellow coders! Today, let’s delve into a classic problem in concurrent programming – the Producer-Consumer Problem. We’ll solve this problem in Java, using its robust concurrency control mechanisms. Let’s get started!

Understanding the Problem

The Producer-Consumer problem is a classic example of a multi-process synchronization problem. Here, we have two processes: the producer, which generates data, and the consumer, which consumes it. The challenge lies in making sure that the producer won’t try to add data into a full buffer, and the consumer won’t try to remove data from an empty buffer.

Java Solution

Java’s java.util.concurrent package provides several classes that can help us solve this problem. We’ll be using BlockingQueue – a queue that additionally supports operations that wait for the queue to become non-empty when retrieving an element and wait for space to become available in the queue when storing an element.

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;

class Producer implements Runnable {
    private final BlockingQueue<Integer> sharedQueue;

    public Producer(BlockingQueue<Integer> sharedQueue) {
        this.sharedQueue = sharedQueue;
    }

    @Override
    public void run() {
        for (int i = 0; i < 10; i++) {
            try {
                System.out.println("Produced: " + i);
                sharedQueue.put(i);
                Thread.sleep(100);
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }
    }
}

class Consumer implements Runnable {
    private final BlockingQueue<Integer> sharedQueue;

    public Consumer(BlockingQueue<Integer> sharedQueue) {
        this.sharedQueue = sharedQueue;
    }

    @Override
    public void run() {
        while (true) {
            try {
                System.out.println("Consumed: " + sharedQueue.take());
                Thread.sleep(100);
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }
    }
}

public class ProducerConsumer {
    public static void main(String[] args) {
        BlockingQueue<Integer> sharedQueue = new LinkedBlockingQueue<>();

        Thread producerThread = new Thread(new Producer(sharedQueue));
        Thread consumerThread = new Thread(new Consumer(sharedQueue));

        producerThread.start();
        consumerThread.start();
    }
}

In this code, the producer produces a series of numbers, while the consumer consumes them. The put() method used by the producer will block if the queue is full, and the take() method used by the consumer will block if the queue is empty, thereby solving our problem.

Final Note

The Producer-Consumer problem provides a great opportunity to explore how Java handles concurrency and synchronisation. By leveraging Java’s inbuilt classes and methods, we can provide a simple and efficient solution to this problem. Always remember, concurrency control is an essential tool in your developer’s toolkit. So, keep practicing, keep coding, and until next time, happy learning!

📚 Further Reading & Related Topics

If you’re exploring solving the Producer-Consumer problem in Java, these related articles will provide deeper insights:

• Threads in Java: The Difference Between Calling Start and Run Methods – Learn how Java handles thread execution, a key concept for understanding producer-consumer synchronization.

• Latency Optimization Techniques: Unlocking Performance with Lock-Free Programming, Memory Barriers, and Efficient Data Structures – Explore how advanced concurrency techniques like lock-free programming and memory barriers can optimize producer-consumer implementations.