Semaphore semaphore

 

Limit the number of concurrent accesses to concurrent resources. samephore.acquire(); acquires a license samephore.release(); releases a license.

public class SemaphoreTest implements Runnable {
    Semaphore samephore;
    int id;

    public SemaphoreTest(Semaphore samephore, int id) {
        this.samephore = samephore;
        this.id = id;
    }

    @Override
    public void run() {

        // TODO Auto-generated method stub
        try {
            samephore.acquire();
            Thread.sleep(1000);
            System.out.println( "Customer ID" + id + "Task being processed" );
            samephore.release();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    public static void main(String[] args) {
        Semaphore samephore = new Semaphore(10, true ); // Limit the number of concurrent accesses to 10 true to use fair mode. advanced first traversal 
        for ( int i = 0; i < 20; i++ ) {
             new Thread( new SemaphoreTest(samephore, i)).start();;
        }
    }

}

Simulate 10 windows for handling tasks in a bank. samephore.acquire() If there are 10 tasks that have obtained permission and have not been released, others are waiting for a task that is executing permission to release the permission to enter