opendaylight/md-sal/sal-clustering-commons/src/main/java/org/opendaylight/controller/cluster/common/actor/ExplicitAsk.java

   1 /*
   2  * Copyright (c) 2016 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.controller.cluster.common.actor;
   9
  10 import akka.actor.ActorRef;
  11 import akka.actor.ActorSelection;
  12 import akka.pattern.ExplicitAskSupport;
  13 import akka.util.Timeout;
  14 import com.google.common.annotations.Beta;
  15 import java.util.function.Function;
  16 import scala.Function1;
  17 import scala.concurrent.Future;
  18 import scala.runtime.AbstractFunction1;
  19
  20 /**
  21  * Unfortunately Akka's explicit ask pattern does not work with its Java API, as it fails to invoke passed message.
  22  * In order to make this work for now, we tap directly into ExplicitAskSupport and use a Scala function instead
  23  * of akka.japi.Function.
  24  *
  25  * @author Robert Varga
  26  */
  27 @Beta
  28 public final class ExplicitAsk {
  29     private static final ExplicitAskSupport ASK_SUPPORT = akka.pattern.extended.package$.MODULE$;
  30
  31     private ExplicitAsk() {
  32         throw new UnsupportedOperationException();
  33     }
  34
  35     public static <T> Function1<ActorRef, T> toScala(final Function<ActorRef, T> function) {
  36         return new AbstractFunction1<ActorRef, T>() {
  37             @Override
  38             public T apply(final ActorRef askSender) {
  39                 return function.apply(askSender);
  40             }
  41         };
  42     }
  43
  44     @SuppressWarnings("unchecked")
  45     public static Future<Object> ask(final ActorRef actor, final Function1<ActorRef, ?> function,
  46             final Timeout timeout) {
  47         return ASK_SUPPORT.ask(actor, (Function1<ActorRef, Object>)function, timeout);
  48     }
  49
  50     @SuppressWarnings("unchecked")
  51     public static Future<Object> ask(final ActorSelection actor, final Function1<ActorRef, ?> function,
  52             final Timeout timeout) {
  53         return ASK_SUPPORT.ask(actor, (Function1<ActorRef, Object>)function, timeout);
  54     }
  55
  56     public static Future<Object> ask(final ActorRef actor, final Function<ActorRef, ?> function,
  57             final Timeout timeout) {
  58         return ask(actor, toScala(function), timeout);
  59     }
  60
  61     public static Future<Object> ask(final ActorSelection actor, final Function<ActorRef, ?> function,
  62             final Timeout timeout) {
  63         return ask(actor, toScala(function), timeout);
  64     }
  65 }