14. Multi-Threaded Producer-Consumer Architecture with BlockingQueues • Low-Level Design (LLD) & Object-Oriented Machine Coding • Rishabh Ki Kaksha

Multiple Producer threads data produce karte hain aur multiple Consumer threads process karte hain:
*   Agar Buffer **Full** ho $\rightarrow$ Producers must **Wait / Block**!
*   Agar Buffer **Empty** ho $\rightarrow$ Consumers must **Wait / Block**!

---

### 2. Thread-Safe Bounded Blocking Queue in Java / C++

```java
import java.util.LinkedList;
import java.util.Queue;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;

public class CustomBlockingQueue<T> {
    private final Queue<T> queue = new LinkedList<>();
    private final int capacity;
    private final ReentrantLock lock = new ReentrantLock();
    private final Condition notFull = lock.newCondition();
    private final Condition notEmpty = lock.newCondition();

public CustomBlockingQueue(int capacity) { this.capacity = capacity; }

public void put(T item) throws InterruptedException {
        lock.lock();
        try {
            while (queue.size() == capacity) {
                notFull.await(); // Buffer full -> Producer sleeps!
            }
            queue.add(item);
            notEmpty.signal();   // Signal sleeping consumers!
        } finally {
            lock.unlock();
        }
    }

public T take() throws InterruptedException {
        lock.lock();
        try {
            while (queue.isEmpty()) {
                notEmpty.await(); // Buffer empty -> Consumer sleeps!
            }
            T item = queue.poll();
            notFull.signal();     // Signal sleeping producers!
            return item;
        } finally {
            lock.unlock();
        }
    }
}
```

---

### 3. Master Comparison Matrix

---

### 4. Interview Ke 3 Sawal Is Topic Se

1. **`if (queue.isEmpty())` ke badle `while (queue.isEmpty())` loop kyu zaroori hota hai?** -> Spurious Wakeups se bachne ke liye taaki thread jaagne ke baad condition dubara verify kare.
2. **`signal()` aur `signalAll()` me kya difference hai?** -> `signal()` 1 waiting thread ko jagata hai (No Thundering Herd problem); `signalAll()` saare waiting threads ko jagata hai.
3. **Disruptor pattern (LMAX) BlockingQueue se 10x fast kyu hota hai?** -> Lock-free RingBuffer aur CPU Cache-Line padding use karke false sharing eliminate karta hai.

---
**Next Topic:** 15. Thread Pool Executor Implementation & Task Scheduling Engine

Loading lesson content...

Python 3.12

Full IDE

Live Execution Terminal

Click "Execute Live" to run code.
                

Lesson Mastery AI Quiz

AI Doubt Solver

CERTIFICATE OF COMPLETION

Rishabh Gehlot

PHP 8+ & Laravel 11 Master Track