[Ch15] Adding a latch example to the predictable run order, and a very crude performance test. (6fa08a97) · Commits · examples / Head First Java 3rd Edition

src/main/java/ch15/PredictableRunOrder.java

+27 −0

Changes for src/main/java/ch15/PredictableRunOrder.java: 27 added lines, 0 removed lines.
Original line number	Diff line number	Diff line
		@@ -4,9 +4,12 @@ import java.util.concurrent.*;

		public class PredictableRunOrder {
		public static void main(String[] args) throws InterruptedException {
		long startTime = System.currentTimeMillis();
		for (int i = 0; i < 100; i++) {
		PredictableSleep.main(args);
		}
		long endTime = System.currentTimeMillis();
		System.out.println(endTime-startTime);
		}
		}

		@@ -16,6 +19,7 @@ class PredictableSleep {
		executor.execute(() -> sleepThenPrint());
		System.out.println("back in main");
		executor.shutdown();
		executor.awaitTermination(2, TimeUnit.SECONDS);
		}

		private static void sleepThenPrint() {
		@@ -34,6 +38,7 @@ class SleepWithTimeUnit {
		executor.execute(() -> sleepThenPrint());
		System.out.println("back in main");
		executor.shutdown();
		executor.awaitTermination(2, TimeUnit.SECONDS);
		}

		private static void sleepThenPrint() {
		@@ -45,3 +50,25 @@ class SleepWithTimeUnit {
		System.out.println("top o’ the stack");
		}
		}

		class PredictableLatch {
		public static void main (String[] args) throws InterruptedException {
		ExecutorService executor = Executors.newSingleThreadExecutor();
		CountDownLatch latch = new CountDownLatch(1);
		executor.execute(() -> waitForLatchThenPrint(latch));
		System.out.println("back in main");
		latch.countDown();
		executor.shutdown();
		executor.awaitTermination(2, TimeUnit.SECONDS);
		}

		private static void waitForLatchThenPrint(CountDownLatch latch) {
		try {
		latch.await();
		} catch (InterruptedException e) {
		e.printStackTrace();
		}
		System.out.println("top o’ the stack");
		}
		}