Executors example

winterbe · winterbe · commit 89a257129873 · 2015-03-29T09:10:14.000+02:00
diff --git a/src/com/winterbe/java8/samples/concurrent/Executors1.java b/src/com/winterbe/java8/samples/concurrent/Executors1.java
@@ -19,16 +19,17 @@ private static void test1(long seconds) {
         executor.submit(() -> {
             try {
                 TimeUnit.SECONDS.sleep(seconds);
-                System.out.println("task finished: " + Thread.currentThread().getName());
+                String name = Thread.currentThread().getName();
+                System.out.println("task finished: " + name);
             }
             catch (InterruptedException e) {
                 System.err.println("task interrupted");
             }
         });
-        shutdown(executor);
+        stop(executor);
     }
 
-    static void shutdown(ExecutorService executor) {
+    static void stop(ExecutorService executor) {
         try {
             System.out.println("attempt to shutdown executor");
             executor.shutdown();
@@ -38,6 +39,9 @@ static void shutdown(ExecutorService executor) {
             System.err.println("termination interrupted");
         }
         finally {
+            if (!executor.isTerminated()) {
+                System.err.println("killing non-finished tasks");
+            }
             executor.shutdownNow();
             System.out.println("shutdown finished");
         }
diff --git a/src/com/winterbe/java8/samples/concurrent/Executors2.java b/src/com/winterbe/java8/samples/concurrent/Executors2.java
@@ -19,7 +19,7 @@ public static void main(String[] args) throws ExecutionException, InterruptedExc
     }
 
     private static void test3() throws InterruptedException, ExecutionException, TimeoutException {
-        ExecutorService executor = Executors.newSingleThreadExecutor();
+        ExecutorService executor = Executors.newFixedThreadPool(1);
 
         Future<Integer> future = executor.submit(() -> {
             try {
@@ -35,7 +35,7 @@ private static void test3() throws InterruptedException, ExecutionException, Tim
     }
 
     private static void test2() throws InterruptedException, ExecutionException {
-        ExecutorService executor = Executors.newSingleThreadExecutor();
+        ExecutorService executor = Executors.newFixedThreadPool(1);
 
         Future<Integer> future = executor.submit(() -> {
             try {
@@ -52,7 +52,7 @@ private static void test2() throws InterruptedException, ExecutionException {
     }
 
     private static void test1() throws InterruptedException, ExecutionException {
-        ExecutorService executor = Executors.newSingleThreadExecutor();
+        ExecutorService executor = Executors.newFixedThreadPool(1);
 
         Future<Integer> future = executor.submit(() -> {
             try {
diff --git a/src/com/winterbe/java8/samples/concurrent/Executors3.java b/src/com/winterbe/java8/samples/concurrent/Executors3.java
@@ -16,12 +16,12 @@
 public class Executors3 {
 
     public static void main(String[] args) throws InterruptedException, ExecutionException {
-//        test1();
+        test1();
 //        test2();
 //        test3();
 
 //        test4();
-        test5();
+//        test5();
     }
 
     private static void test5() throws InterruptedException, ExecutionException {
@@ -70,26 +70,37 @@ private static void test4() throws InterruptedException {
 
     private static void test3() {
         ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
-        executor.scheduleWithFixedDelay(() -> {
+
+        Runnable task = () -> {
             try {
                 TimeUnit.SECONDS.sleep(2);
                 System.out.println("Scheduling: " + System.nanoTime());
             }
             catch (InterruptedException e) {
                 System.err.println("task interrupted");
             }
-        }, 0, 1, TimeUnit.SECONDS);
+        };
+
+        executor.scheduleWithFixedDelay(task, 0, 1, TimeUnit.SECONDS);
     }
 
     private static void test2() {
         ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
-        executor.scheduleAtFixedRate(() -> System.out.println("Scheduling: " + System.nanoTime()), 0, 1, TimeUnit.SECONDS);
+        Runnable task = () -> System.out.println("Scheduling: " + System.nanoTime());
+        int initialDelay = 0;
+        int period = 1;
+        executor.scheduleAtFixedRate(task, initialDelay, period, TimeUnit.SECONDS);
     }
 
     private static void test1() throws InterruptedException {
         ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
-        ScheduledFuture<?> future = executor.schedule(() -> System.out.println("Scheduling: " + System.nanoTime()), 3, TimeUnit.SECONDS);
+
+        Runnable task = () -> System.out.println("Scheduling: " + System.nanoTime());
+        int delay = 3;
+        ScheduledFuture<?> future = executor.schedule(task, delay, TimeUnit.SECONDS);
+
         TimeUnit.MILLISECONDS.sleep(1337);
+
         long remainingDelay = future.getDelay(TimeUnit.MILLISECONDS);
         System.out.printf("Remaining Delay: %sms\n", remainingDelay);
     }
diff --git a/src/com/winterbe/java8/samples/concurrent/Threads1.java b/src/com/winterbe/java8/samples/concurrent/Threads1.java
@@ -9,8 +9,8 @@ public class Threads1 {
 
     public static void main(String[] args) {
         test1();
-        test2();
-        test3();
+//        test2();
+//        test3();
     }
 
     private static void test3() {
@@ -46,13 +46,16 @@ private static void test2() {
     }
 
     private static void test1() {
-        Runnable runnable = () -> System.out.println("Hello " + Thread.currentThread().getName());
+        Runnable runnable = () -> {
+            String threadName = Thread.currentThread().getName();
+            System.out.println("Hello " + threadName);
+        };
 
         runnable.run();
 
         Thread thread = new Thread(runnable);
         thread.start();
 
-        System.out.println("Nachos!");
+        System.out.println("Done!");
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -19,16 +19,17 @@ private static void test1(long seconds) {`
`19`	`19`	`executor.submit(() -> {`
`20`	`20`	`try {`
`21`	`21`	`TimeUnit.SECONDS.sleep(seconds);`
`22`		`- System.out.println("task finished: " + Thread.currentThread().getName());`
	`22`	`+ String name = Thread.currentThread().getName();`
	`23`	`+ System.out.println("task finished: " + name);`
`23`	`24`	`}`
`24`	`25`	`catch (InterruptedException e) {`
`25`	`26`	`System.err.println("task interrupted");`
`26`	`27`	`}`
`27`	`28`	`});`
`28`		`- shutdown(executor);`
	`29`	`+ stop(executor);`
`29`	`30`	`}`
`30`	`31`
`31`		`- static void shutdown(ExecutorService executor) {`
	`32`	`+ static void stop(ExecutorService executor) {`
`32`	`33`	`try {`
`33`	`34`	`System.out.println("attempt to shutdown executor");`
`34`	`35`	`executor.shutdown();`
`@@ -38,6 +39,9 @@ static void shutdown(ExecutorService executor) {`
`38`	`39`	`System.err.println("termination interrupted");`
`39`	`40`	`}`
`40`	`41`	`finally {`
	`42`	`+ if (!executor.isTerminated()) {`
	`43`	`+ System.err.println("killing non-finished tasks");`
	`44`	`+ }`
`41`	`45`	`executor.shutdownNow();`
`42`	`46`	`System.out.println("shutdown finished");`
`43`	`47`	`}`
Original file line number	Diff line number	Diff line change
`@@ -19,7 +19,7 @@ public static void main(String[] args) throws ExecutionException, InterruptedExc`
`19`	`19`	`}`
`20`	`20`
`21`	`21`	`private static void test3() throws InterruptedException, ExecutionException, TimeoutException {`
`22`		`- ExecutorService executor = Executors.newSingleThreadExecutor();`
	`22`	`+ ExecutorService executor = Executors.newFixedThreadPool(1);`
`23`	`23`
`24`	`24`	`Future<Integer> future = executor.submit(() -> {`
`25`	`25`	`try {`
`@@ -35,7 +35,7 @@ private static void test3() throws InterruptedException, ExecutionException, Tim`
`35`	`35`	`}`
`36`	`36`
`37`	`37`	`private static void test2() throws InterruptedException, ExecutionException {`
`38`		`- ExecutorService executor = Executors.newSingleThreadExecutor();`
	`38`	`+ ExecutorService executor = Executors.newFixedThreadPool(1);`
`39`	`39`
`40`	`40`	`Future<Integer> future = executor.submit(() -> {`
`41`	`41`	`try {`
`@@ -52,7 +52,7 @@ private static void test2() throws InterruptedException, ExecutionException {`
`52`	`52`	`}`
`53`	`53`
`54`	`54`	`private static void test1() throws InterruptedException, ExecutionException {`
`55`		`- ExecutorService executor = Executors.newSingleThreadExecutor();`
	`55`	`+ ExecutorService executor = Executors.newFixedThreadPool(1);`
`56`	`56`
`57`	`57`	`Future<Integer> future = executor.submit(() -> {`
`58`	`58`	`try {`
Original file line number	Diff line number	Diff line change
`@@ -9,8 +9,8 @@ public class Threads1 {`
`9`	`9`
`10`	`10`	`public static void main(String[] args) {`
`11`	`11`	`test1();`
`12`		`- test2();`
`13`		`- test3();`
	`12`	`+// test2();`
	`13`	`+// test3();`
`14`	`14`	`}`
`15`	`15`
`16`	`16`	`private static void test3() {`
`@@ -46,13 +46,16 @@ private static void test2() {`
`46`	`46`	`}`
`47`	`47`
`48`	`48`	`private static void test1() {`
`49`		`- Runnable runnable = () -> System.out.println("Hello " + Thread.currentThread().getName());`
	`49`	`+ Runnable runnable = () -> {`
	`50`	`+ String threadName = Thread.currentThread().getName();`
	`51`	`+ System.out.println("Hello " + threadName);`
	`52`	`+ };`
`50`	`53`
`51`	`54`	`runnable.run();`
`52`	`55`
`53`	`56`	`Thread thread = new Thread(runnable);`
`54`	`57`	`thread.start();`
`55`	`58`
`56`		`- System.out.println("Nachos!");`
	`59`	`+ System.out.println("Done!");`
`57`	`60`	`}`
`58`	`61`	`}`