opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/sharding/RoleChangeListenerActor.java

   1 /*
   2  * Copyright (c) 2017 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
   9 package org.opendaylight.controller.cluster.sharding;
  10
  11 import akka.actor.ActorRef;
  12 import akka.actor.Props;
  13 import com.google.common.base.Preconditions;
  14 import org.opendaylight.controller.cluster.common.actor.AbstractUntypedActor;
  15 import org.opendaylight.controller.cluster.dom.api.LeaderLocation;
  16 import org.opendaylight.controller.cluster.dom.api.LeaderLocationListener;
  17 import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
  18 import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
  19 import org.opendaylight.controller.cluster.notifications.RoleChangeNotification;
  20
  21 /**
  22  * Proxy actor which acts as a facade for user-provided
  23  * {@link LeaderLocationListener}. It subscribes for {@link LeaderStateChanged}
  24  * notifications in its pre start hook and translates them to
  25  * {@link LeaderLocationListener#onLeaderLocationChanged(LeaderLocation)}
  26  * events.
  27  */
  28 public final class RoleChangeListenerActor extends AbstractUntypedActor {
  29     private final LeaderLocationListener leaderLocationListener;
  30     private final ActorRef roleChangeNotifier;
  31
  32     private RoleChangeListenerActor(final ActorRef roleChangeNotifier, final LeaderLocationListener listener) {
  33         this.roleChangeNotifier = Preconditions.checkNotNull(roleChangeNotifier);
  34         this.leaderLocationListener = Preconditions.checkNotNull(listener);
  35     }
  36
  37     @Override
  38     public void preStart() throws Exception {
  39         super.preStart();
  40         roleChangeNotifier.tell(new RegisterRoleChangeListener(), getSelf());
  41     }
  42
  43     @Override
  44     protected void handleReceive(final Object message) {
  45         if (message instanceof RoleChangeNotification) {
  46             ignoreMessage(message);
  47         } else if (message instanceof LeaderStateChanged) {
  48             onLeaderStateChanged((LeaderStateChanged) message);
  49         } else {
  50             unknownMessage(message);
  51         }
  52     }
  53
  54     private void onLeaderStateChanged(final LeaderStateChanged message) {
  55         final LeaderLocation newLocation;
  56         if (message.getLeaderId() == null) {
  57             newLocation = LeaderLocation.UNKNOWN;
  58         } else if (message.getMemberId().equals(message.getLeaderId())) {
  59             newLocation = LeaderLocation.LOCAL;
  60         } else {
  61             newLocation = LeaderLocation.REMOTE;
  62         }
  63
  64         // TODO should we wrap this in try catch block?
  65         leaderLocationListener.onLeaderLocationChanged(newLocation);
  66     }
  67
  68     public static Props props(final ActorRef roleChangeNotifier, final LeaderLocationListener listener) {
  69         return Props.create(RoleChangeListenerActor.class, roleChangeNotifier, listener);
  70     }
  71 }