PrintNumbersUsingReentrantLock.java

package practise.leetCode;
import java.util.Scanner;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
class NumberPrinter1 {
    private int number = 1;
    private final int max;
    private int turn = 1;
    private final ReentrantLock lock = new ReentrantLock();
    private final Condition condition = lock.newCondition();
    public NumberPrinter1(int max) {
        this.max = max;
    }
    public void printThread1() {
        while (true) {
            lock.lock();
            try {
                while (number <= max && turn != 1) {
                    condition.await();
                }
                if (number > max) {
                    condition.signalAll();
                    return;
                }
                System.out.println(Thread.currentThread().getName() + " : " + number);
                number++;
                turn = 2;
                condition.signalAll();
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            } finally {
                lock.unlock();
            }
        }
    }
    public void printThread2() {
        while (true) {
            lock.lock();
            try {
                while (number <= max && turn != 2) {
                    condition.await();
                }
                if (number > max) {
                    condition.signalAll();
                    return;
                }
                System.out.println(Thread.currentThread().getName()
                        + " : " + number);
                number++;
                turn = 3;
                condition.signalAll();
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            } finally {
                lock.unlock();
            }
        }
    }
    public void printThread3() {
        while (true) {
            lock.lock();
            try {
                while (number <= max && turn != 3) {
                    condition.await();
                }
                if (number > max) {
                    condition.signalAll();
                    return;
                }
                System.out.println(Thread.currentThread().getName()
                        + " : " + number);
                number++;
                turn = 1;
                condition.signalAll();
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            } finally {
                lock.unlock();
            }
        }
    }
}
public class PrintNumbersUsingReentrantLock {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter N : ");
        int n = scanner.nextInt();
        NumberPrinter1 printer = new NumberPrinter1(n);
        Thread t1 = new Thread(printer::printThread1, "Thread-1");
        Thread t2 = new Thread(printer::printThread2, "Thread-2");
        Thread t3 = new Thread(printer::printThread3, "Thread-3");
        t1.start();
        t2.start();
        t3.start();
    }
}