future to callback

Author: meowpunch

src/main/java/concurrency/future/CallbackEx.java

@@ -0,0 +1,14 @@
+package concurrency.future;
+
+public class CallbackEx {
+
+  interface Callback {
+    void onSuccess();
+  }
+
+  public static void main(String[] args) {
+
+
+  }
+
+}

src/main/java/concurrency/future/FutureEx.java

@@ -29,10 +29,10 @@ public static void main(String[] args) throws InterruptedException, ExecutionExc
 
     log.debug("Is the async task done? " + future.isDone());
     log.debug("Processing the other task");
-    Thread.sleep(2000);
+    Thread.sleep(1000);
 
     log.debug("Is the async task done? " + future.isDone());
-    log.debug("The async result is " + future.get()); // blocking, wait the async result.
+    System.out.println("The async result is " + future.get()); // blocking, wait the async result.
     log.debug("Exit " + (System.currentTimeMillis() - startTime));
   }
 }

src/main/java/concurrency/future/FutureTaskEx.java

@@ -0,0 +1,48 @@
+package concurrency.future;
+
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.FutureTask;
+import lombok.extern.slf4j.Slf4j;
+
+@Slf4j
+public class FutureTaskEx {
+
+  public static void main(String[] args) throws InterruptedException, ExecutionException {
+    log.debug("Enter");
+    final ExecutorService executorService = Executors.newCachedThreadPool();
+
+    final long startTime = System.currentTimeMillis();
+    FutureTask<String> future = new FutureTask<>(
+        () -> {
+          log.debug("Processing task asynchronously");
+          try {
+            Thread.sleep(2000);
+          } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+          }
+
+          return "AsyncResult";
+        }
+    ) {
+      @Override
+      protected void done() {
+        try {
+          System.out.println("The async result is " + get());
+        } catch (InterruptedException | ExecutionException e) {
+          throw new RuntimeException(e);
+        }
+      }
+    };
+
+    executorService.execute(future);
+    executorService.shutdown();
+
+    log.debug("Is the async task done? " + future.isDone());
+    log.debug("Processing the other task");
+    Thread.sleep(1000);
+    log.debug("Exit " + (System.currentTimeMillis() - startTime));
+  }
+}