Executors example

winterbe · winterbe · commit 15bf517ae667 · 2015-03-27T07:30:37.000+01:00
diff --git a/src/com/winterbe/java8/samples/concurrent/Executors1.java b/src/com/winterbe/java8/samples/concurrent/Executors1.java
@@ -0,0 +1,45 @@
+package com.winterbe.java8.samples.concurrent;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * @author Benjamin Winterberg
+ */
+public class Executors1 {
+
+    public static void main(String[] args) {
+        test1(3);
+//        test1(7);
+    }
+
+    private static void test1(long seconds) {
+        ExecutorService executor = Executors.newSingleThreadExecutor();
+        executor.submit(() -> {
+            try {
+                TimeUnit.SECONDS.sleep(seconds);
+                System.out.println("task finished: " + Thread.currentThread().getName());
+            }
+            catch (InterruptedException e) {
+                System.err.println("task interrupted");
+            }
+        });
+        shutdown(executor);
+    }
+
+    static void shutdown(ExecutorService executor) {
+        try {
+            System.out.println("attempt to shutdown executor");
+            executor.shutdown();
+            executor.awaitTermination(5, TimeUnit.SECONDS);
+        }
+        catch (InterruptedException e) {
+            System.err.println("termination interrupted");
+        }
+        finally {
+            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
@@ -0,0 +1,77 @@
+package com.winterbe.java8.samples.concurrent;
+
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+/**
+ * @author Benjamin Winterberg
+ */
+public class Executors2 {
+
+    public static void main(String[] args) throws ExecutionException, InterruptedException, TimeoutException {
+//        test1();
+//        test2();
+        test3();
+    }
+
+    private static void test3() throws InterruptedException, ExecutionException, TimeoutException {
+        ExecutorService executor = Executors.newSingleThreadExecutor();
+
+        Future<Integer> future = executor.submit(() -> {
+            try {
+                TimeUnit.SECONDS.sleep(2);
+                return 123;
+            }
+            catch (InterruptedException e) {
+                throw new IllegalStateException("task interrupted", e);
+            }
+        });
+
+        future.get(1, TimeUnit.SECONDS);
+    }
+
+    private static void test2() throws InterruptedException, ExecutionException {
+        ExecutorService executor = Executors.newSingleThreadExecutor();
+
+        Future<Integer> future = executor.submit(() -> {
+            try {
+                TimeUnit.SECONDS.sleep(1);
+                return 123;
+            }
+            catch (InterruptedException e) {
+                throw new IllegalStateException("task interrupted", e);
+            }
+        });
+
+        executor.shutdownNow();
+        future.get();
+    }
+
+    private static void test1() throws InterruptedException, ExecutionException {
+        ExecutorService executor = Executors.newSingleThreadExecutor();
+
+        Future<Integer> future = executor.submit(() -> {
+            try {
+                TimeUnit.SECONDS.sleep(1);
+                return 123;
+            }
+            catch (InterruptedException e) {
+                throw new IllegalStateException("task interrupted", e);
+            }
+        });
+
+        System.out.println("future done: " + future.isDone());
+
+        Integer result = future.get();
+
+        System.out.println("future done: " + future.isDone());
+        System.out.print("result: " + result);
+
+        executor.shutdownNow();
+    }
+
+}
