junit5

rendevous.java

import java.util.concurrent.Semaphore;
import static org.junit.jupiter.api.Assertions.assertEquals;

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.RepeatedTest;
import org.junit.jupiter.api.Test;

@DisplayName("Little book of semaphores - Rendevous")
class Rendevous extends Thread {

//	public static void main(String[] args) {
//		Semaphore aDone = new Semaphore(0);
//		Semaphore bDone = new Semaphore(0);
//		new Rendevous("a",aDone,bDone).start();
//		new Rendevous("b",bDone,aDone).start();
//	}
	
	//@RepeatedTest(4) // Dynamic JavaScript expression.
	@Test
	@DisplayName("Rendevous a before b")
	void test1(){
		Semaphore aDone = new Semaphore(0);
		Semaphore bDone = new Semaphore(0);
		new Rendevous("a",aDone,bDone).start();
		new Rendevous("b",bDone,aDone).start();
	}
	
	
	@DisplayName("Rendevous b before a")
	@Test
	//@RepeatedTest(4) // Dynamic JavaScript expression.
	void test2(){
		Semaphore aDone = new Semaphore(0);
		Semaphore bDone = new Semaphore(0);
		new Rendevous("b",bDone,aDone).start();
		new Rendevous("a",aDone,bDone).start();
	}
	
	private String letter;
	private Semaphore iArrived;
	private Semaphore uArrived;
	
	Rendevous(String letter,Semaphore myMutex,Semaphore otherMutex){
		this.letter=letter;
		this.iArrived=myMutex;
		this.uArrived=otherMutex;
	}
	
	@Override
	public void run() {
		step1();
		try {
			iArrived.release(); //block
			uArrived.acquire(); //signal

		} catch (InterruptedException e) {
			System.out.println(letter+" interrupted");
	
		}
		step2();
	}
	
	void step1(){
		System.out.println(letter+"1 done");
	}

	void step2() {
		System.out.println(letter+"2 done");
	}

}