[Ch15] Creating an example to test the main ExecutorServices to see how they behave. (bae326e2) · Commits · examples / Head First Java 3rd Edition

src/main/java/ch15/ThreadPools.java

+50 −2

Changes for src/main/java/ch15/ThreadPools.java: 50 added lines, 2 removed lines.
Original line number	Diff line number	Diff line
		@@ -2,11 +2,13 @@ package ch15;

		import java.util.concurrent.ExecutorService;
		import java.util.concurrent.Executors;
		import java.util.concurrent.ScheduledExecutorService;
		import java.util.concurrent.TimeUnit;

		public class ThreadPools {

		public static void main(String[] args) {
		createCachedThreadPool();
		public static void main(String[] args) throws InterruptedException {
		createWorkStealingPool();
		}

		private static void createCachedThreadPool() {
		@@ -27,6 +29,52 @@ public class ThreadPools {
		threadPool.shutdown();
		}

		private static void createScheduledThreadPoolAndSchedule() {
		ScheduledExecutorService threadPool = Executors.newScheduledThreadPool(2);
		threadPool.schedule(() -> System.out.println("1"), 2, TimeUnit.SECONDS);
		threadPool.schedule(() -> System.out.println("2"), 1500, TimeUnit.MILLISECONDS);
		threadPool.schedule(() -> System.out.println("3"), 1, TimeUnit.SECONDS);
		threadPool.schedule(() -> System.out.println("4"), 500, TimeUnit.MILLISECONDS);
		threadPool.shutdown();
		}

		private static void createScheduledThreadPoolAndScheduleAtFixedRate() throws InterruptedException {
		ScheduledExecutorService threadPool = Executors.newScheduledThreadPool(2);
		threadPool.scheduleAtFixedRate(() -> System.out.println("1"), 400, 1000, TimeUnit.MILLISECONDS);
		threadPool.scheduleAtFixedRate(() -> System.out.println("2"), 300, 2000, TimeUnit.MILLISECONDS);
		threadPool.scheduleAtFixedRate(() -> System.out.println("3"), 200, 3000, TimeUnit.MILLISECONDS);
		threadPool.scheduleAtFixedRate(() -> System.out.println("4"), 100, 4000, TimeUnit.MILLISECONDS);
		TimeUnit.SECONDS.sleep(20);
		threadPool.shutdown();
		}

		private static void createSingleThreadExecutor() {
		ExecutorService threadPool = Executors.newSingleThreadExecutor();
		threadPool.execute(() -> run("Job 1"));
		threadPool.execute(() -> run("Job 2"));
		threadPool.execute(() -> run("Job 3"));
		threadPool.execute(() -> run("Job 4"));
		threadPool.shutdown();
		}

		private static void createWorkStealingPool() throws InterruptedException {
		ExecutorService threadPool = Executors.newWorkStealingPool();
		threadPool.execute(() -> run("Job 1"));
		threadPool.execute(() -> run("Job 2"));
		threadPool.execute(() -> run("Job 3"));
		threadPool.execute(() -> run("Job 4"));
		threadPool.execute(() -> run("Job 5"));
		threadPool.execute(() -> run("Job 6"));
		threadPool.execute(() -> run("Job 7"));
		threadPool.execute(() -> run("Job 8"));
		threadPool.execute(() -> run("Job 9"));
		threadPool.execute(() -> run("Job 10"));
		threadPool.execute(() -> run("Job 11"));
		threadPool.execute(() -> run("Job 12"));
		threadPool.shutdown();
		threadPool.awaitTermination(20, TimeUnit.SECONDS);
		}

		public static void run(String jobName) {
		for (int i = 0; i < 25; i++) {
		String threadName = Thread.currentThread().getName();