opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/entityownership/EntityOwnershipListenerSupport.java

   1 /*
   2  * Copyright (c) 2015 Brocade Communications 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.datastore.entityownership;
   9
  10 import akka.actor.ActorContext;
  11 import akka.actor.ActorRef;
  12 import akka.actor.PoisonPill;
  13 import com.google.common.collect.HashMultimap;
  14 import com.google.common.collect.Multimap;
  15 import java.util.Collection;
  16 import java.util.IdentityHashMap;
  17 import java.util.Map;
  18 import org.opendaylight.controller.cluster.datastore.entityownership.messages.EntityOwnershipChanged;
  19 import org.opendaylight.controller.md.sal.common.api.clustering.Entity;
  20 import org.opendaylight.controller.md.sal.common.api.clustering.EntityOwnershipListener;
  21 import org.slf4j.Logger;
  22 import org.slf4j.LoggerFactory;
  23
  24 /**
  25  * Manages EntityOwnershipListener registrations and notifications for the EntityOwnershipShard.
  26  *
  27  * @author Thomas Pantelis
  28  */
  29 class EntityOwnershipListenerSupport {
  30     private static final Logger LOG = LoggerFactory.getLogger(EntityOwnershipListenerSupport.class);
  31
  32     private final ActorContext actorContext;
  33     private final Map<EntityOwnershipListener, ListenerActorRefEntry> listenerActorMap = new IdentityHashMap<>();
  34     private final Multimap<Entity, EntityOwnershipListener> entityListenerMap = HashMultimap.create();
  35
  36     EntityOwnershipListenerSupport(ActorContext actorContext) {
  37         this.actorContext = actorContext;
  38     }
  39
  40     void addEntityOwnershipListener(Entity entity, EntityOwnershipListener listener) {
  41         LOG.debug("Adding EntityOwnershipListener {} for {}", listener, entity);
  42
  43         if(entityListenerMap.put(entity, listener)) {
  44             ListenerActorRefEntry listenerEntry = listenerActorMap.get(listener);
  45             if(listenerEntry == null) {
  46                 listenerActorMap.put(listener, new ListenerActorRefEntry());
  47             } else {
  48                 listenerEntry.referenceCount++;
  49             }
  50         }
  51     }
  52
  53     void removeEntityOwnershipListener(Entity entity, EntityOwnershipListener listener) {
  54         LOG.debug("Removing EntityOwnershipListener {} for {}", listener, entity);
  55
  56         if(entityListenerMap.remove(entity, listener)) {
  57             ListenerActorRefEntry listenerEntry = listenerActorMap.get(listener);
  58
  59             LOG.debug("Found {}", listenerEntry);
  60
  61             listenerEntry.referenceCount--;
  62             if(listenerEntry.referenceCount <= 0) {
  63                 listenerActorMap.remove(listener);
  64
  65                 if(listenerEntry.actorRef != null) {
  66                     LOG.debug("Killing EntityOwnershipListenerActor {}", listenerEntry.actorRef);
  67                     listenerEntry.actorRef.tell(PoisonPill.getInstance(), ActorRef.noSender());
  68                 }
  69             }
  70         }
  71     }
  72
  73     void notifyEntityOwnershipListeners(Entity entity, boolean wasOwner, boolean isOwner) {
  74         Collection<EntityOwnershipListener> listeners = entityListenerMap.get(entity);
  75         if(listeners.isEmpty()) {
  76             return;
  77         }
  78
  79         EntityOwnershipChanged changed = new EntityOwnershipChanged(entity, wasOwner, isOwner);
  80         for(EntityOwnershipListener listener: listeners) {
  81             ActorRef listenerActor = listenerActorFor(listener);
  82
  83             LOG.debug("Notifying EntityOwnershipListenerActor {} with {}", listenerActor,changed);
  84
  85             listenerActor.tell(changed, ActorRef.noSender());
  86         }
  87     }
  88
  89     private ActorRef listenerActorFor(EntityOwnershipListener listener) {
  90         return listenerActorMap.get(listener).actorFor(listener);
  91     }
  92
  93     private class ListenerActorRefEntry {
  94         ActorRef actorRef;
  95         int referenceCount = 1;
  96
  97         ActorRef actorFor(EntityOwnershipListener listener) {
  98             if(actorRef == null) {
  99                 actorRef = actorContext.actorOf(EntityOwnershipListenerActor.props(listener));
 100
 101                 LOG.debug("Created EntityOwnershipListenerActor {} for listener {}", actorRef, listener);
 102             }
 103
 104             return actorRef;
 105         }
 106
 107         @Override
 108         public String toString() {
 109             return "ListenerActorRefEntry [actorRef=" + actorRef + ", referenceCount=" + referenceCount + "]";
 110         }
 111     }
 112 }