Move routing-in-play -> play-framework

play-framework/introduction/app/controllers/AsyncController.java

@@ -0,0 +1,64 @@
+package controllers;
+
+import akka.actor.ActorSystem;
+
+import javax.inject.*;
+
+import play.*;
+import play.mvc.*;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+import java.util.concurrent.TimeUnit;
+
+import scala.concurrent.duration.Duration;
+import scala.concurrent.ExecutionContextExecutor;
+
+/**
+ * This controller contains an action that demonstrates how to write
+ * simple asynchronous code in a controller. It uses a timer to
+ * asynchronously delay sending a response for 1 second.
+ *
+ * @param actorSystem We need the {@link ActorSystem}'s
+ *                    {@link Scheduler} to run code after a delay.
+ * @param exec        We need a Java {@link Executor} to apply the result
+ *                    of the {@link CompletableFuture} and a Scala
+ *                    {@link ExecutionContext} so we can use the Akka {@link Scheduler}.
+ *                    An {@link ExecutionContextExecutor} implements both interfaces.
+ */
+@Singleton
+public class AsyncController extends Controller {
+
+    private final ActorSystem actorSystem;
+    private final ExecutionContextExecutor exec;
+
+    @Inject
+    public AsyncController(ActorSystem actorSystem, ExecutionContextExecutor exec) {
+        this.actorSystem = actorSystem;
+        this.exec = exec;
+    }
+
+    /**
+     * An action that returns a plain text message after a delay
+     * of 1 second.
+     * <p>
+     * The configuration in the <code>routes</code> file means that this method
+     * will be called when the application receives a <code>GET</code> request with
+     * a path of <code>/message</code>.
+     */
+    public CompletionStage<Result> message() {
+        return getFutureMessage(1, TimeUnit.SECONDS).thenApplyAsync(Results::ok, exec);
+    }
+
+    private CompletionStage<String> getFutureMessage(long time, TimeUnit timeUnit) {
+        CompletableFuture<String> future = new CompletableFuture<>();
+        actorSystem.scheduler().scheduleOnce(
+          Duration.create(time, timeUnit),
+          () -> future.complete("Hi!"),
+          exec
+        );
+        return future;
+    }
+
+}