ExplicitCriticalSection.java

package thinkinginjava.concurrency;

// Using explicit Lock objects to create critical sections.
import java.util.concurrent.locks.*;

// Synchronize the entire method:
class ExplicitPairManager1 extends PairManager {
	private Lock lock = new ReentrantLock();

	public synchronized void increment() {
		lock.lock();
		try {
			p.incrementX();
			p.incrementY();
			store(getPair());
		} finally {
			lock.unlock();
		}
	}
}

// Use a critical section:
class ExplicitPairManager2 extends PairManager {
	private Lock lock = new ReentrantLock();

	public void increment() {
		Pair temp;
		lock.lock();
		try {
			p.incrementX();
			p.incrementY();
			temp = getPair();
		} finally {
			lock.unlock();
		}
		store(temp);
	}
}

public class ExplicitCriticalSection {
	public static void main(String[] args) throws Exception {
		PairManager pman1 = new ExplicitPairManager1(), pman2 = new ExplicitPairManager2();
		CriticalSection.testApproaches(pman1, pman2);
	}
}