ActorContext.getParent for Java API #22413

akka-docs/rst/java/code/jdocs/cluster/FactorialFrontendMain.java

@@ -0,0 +1,71 @@
+package jdocs.cluster;
+
+
+import java.util.concurrent.TimeUnit;
+import scala.concurrent.Await;
+import scala.concurrent.duration.Duration;
+import com.typesafe.config.Config;
+import com.typesafe.config.ConfigFactory;
+
+import akka.actor.ActorSystem;
+import akka.actor.Props;
+import akka.cluster.Cluster;
+
+public class FactorialFrontendMain {
+
+  public static void main(String[] args) {
+    final int upToN = 200;
+
+    final Config config = ConfigFactory.parseString(
+        "akka.cluster.roles = [frontend]").withFallback(
+        ConfigFactory.load("factorial"));
+
+    final ActorSystem system = ActorSystem.create("ClusterSystem", config);
+    system.log().info(
+            "Factorials will start when 2 backend members in the cluster.");
+    //#registerOnUp
+    Cluster.get(system).registerOnMemberUp(new Runnable() {
+      @Override
+      public void run() {
+        system.actorOf(Props.create(FactorialFrontend.class, upToN, true),
+            "factorialFrontend");
+      }
+    });
+    //#registerOnUp
+
+    //#registerOnRemoved
+    Cluster.get(system).registerOnMemberRemoved(new Runnable() {
+      @Override
+      public void run() {
+        // exit JVM when ActorSystem has been terminated
+        final Runnable exit = new Runnable() {
+          @Override public void run() {
+            System.exit(0);
+          }
+        };
+        system.registerOnTermination(exit);
+
+        // shut down ActorSystem
+        system.terminate();
+
+        // In case ActorSystem shutdown takes longer than 10 seconds,
+        // exit the JVM forcefully anyway.
+        // We must spawn a separate thread to not block current thread,
+        // since that would have blocked the shutdown of the ActorSystem.
+        new Thread() {
+          @Override public void run(){
+            try {
+              Await.ready(system.whenTerminated(), Duration.create(10, TimeUnit.SECONDS));
+            } catch (Exception e) {
+              System.exit(-1);
+            }
+
+          }
+        }.start();
+      }
+    });
+    //#registerOnRemoved
+
+  }
+
+}