public static void main(String[] args) {
final Print4 p = new Print4();
new Thread() {
public void run() {
while (true) {
try {
p.print1();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}.start();
new Thread() {
public void run() {
while (true) {
try {
p.print2();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}.start();
new Thread() {
public void run() {
while (true) {
try {
p.print3();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}.start();
}
}
class Print4 {
private int flag = 1;
private ReentrantLock r = new ReentrantLock();
private Condition c1 = r.newCondition();
private Condition c2 = r.newCondition();
private Condition c3 = r.newCondition();
public void print1() throws InterruptedException {
r.lock();
while (flag != 1) {
c1.await();
}
System.out.println("1");
flag = 2;
c2.signal();
r.unlock();
}
public void print2() throws InterruptedException {
r.lock();
while (flag != 2) {
c2.await();
}
System.out.println("2");
flag = 3;
c3.signal();
r.unlock();
}