import java.util.concurrent.Semaphore;

public class SemaphoreExample {

    // Semaphore with 3 permits
    private static final Semaphore semaphore = new Semaphore(3);

    static class SharedResource {
        public void use() {
            try {
                System.out.println(Thread.currentThread().getName() + " is using the resource.");
                Thread.sleep(1000); // Simulating resource use
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            } finally {
                System.out.println(Thread.currentThread().getName() + " is done using the resource.");
            }
        }
    }

    static class Task implements Runnable {
        private SharedResource resource;

        public Task(SharedResource resource) {
            this.resource = resource;
        }

        @Override
        public void run() {
            try {
                // Acquiring the semaphore
                semaphore.acquire();
                resource.use();
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            } finally {
                // Releasing the semaphore
                semaphore.release();
            }
        }
    }

    public static void main(String[] args) {
        SharedResource resource = new SharedResource();

        // Creating and starting five threads
        for (int i = 0; i < 5; i++) {
            new Thread(new Task(resource), "Thread " + (i + 1)).start();
        }
    }
}