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

   1 /*
   2  * Copyright (c) 2015 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.datastore;
   9
  10 import akka.actor.ActorRef;
  11 import akka.actor.ActorSelection;
  12 import java.util.ArrayList;
  13 import java.util.Collection;
  14 import org.opendaylight.controller.cluster.datastore.messages.EnableNotification;
  15 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  16 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListenerReply;
  17 import org.opendaylight.controller.md.sal.dom.api.DOMDataTreeChangeListener;
  18 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  19 import org.slf4j.Logger;
  20 import org.slf4j.LoggerFactory;
  21
  22 final class DataTreeChangeListenerSupport extends LeaderLocalDelegateFactory<RegisterDataTreeChangeListener, ListenerRegistration<DOMDataTreeChangeListener>> {
  23     private static final Logger LOG = LoggerFactory.getLogger(DataTreeChangeListenerSupport.class);
  24     private final ArrayList<DelayedDataTreeListenerRegistration> delayedRegistrations = new ArrayList<>();
  25     private final Collection<ActorSelection> actors = new ArrayList<>();
  26
  27     DataTreeChangeListenerSupport(final Shard shard) {
  28         super(shard);
  29     }
  30
  31     @Override
  32     void onLeadershipChange(final boolean isLeader) {
  33         if (isLeader) {
  34             for (DelayedDataTreeListenerRegistration reg : delayedRegistrations) {
  35                 reg.createDelegate(this);
  36             }
  37             delayedRegistrations.clear();
  38             delayedRegistrations.trimToSize();
  39         }
  40
  41         final EnableNotification msg = new EnableNotification(isLeader);
  42         for (ActorSelection dataChangeListener : actors) {
  43             dataChangeListener.tell(msg, getSelf());
  44         }
  45     }
  46
  47     @Override
  48     void onMessage(final RegisterDataTreeChangeListener registerTreeChangeListener, final boolean isLeader) {
  49         LOG.debug("{}: registerTreeChangeListener for {}, leader: {}", persistenceId(), registerTreeChangeListener.getPath(), isLeader);
  50
  51         final ListenerRegistration<DOMDataTreeChangeListener> registration;
  52         if (!isLeader) {
  53             LOG.debug("{}: Shard is not the leader - delaying registration", persistenceId());
  54
  55             DelayedDataTreeListenerRegistration delayedReg =
  56                     new DelayedDataTreeListenerRegistration(registerTreeChangeListener);
  57             delayedRegistrations.add(delayedReg);
  58             registration = delayedReg;
  59         } else {
  60             registration = createDelegate(registerTreeChangeListener);
  61         }
  62
  63         ActorRef listenerRegistration = createActor(DataTreeChangeListenerRegistrationActor.props(registration));
  64
  65         LOG.debug("{}: registerDataChangeListener sending reply, listenerRegistrationPath = {} ",
  66             persistenceId(), listenerRegistration.path());
  67
  68         tellSender(new RegisterDataTreeChangeListenerReply(listenerRegistration));
  69     }
  70
  71     @Override
  72     ListenerRegistration<DOMDataTreeChangeListener> createDelegate(final RegisterDataTreeChangeListener message) {
  73         ActorSelection dataChangeListenerPath = selectActor(message.getDataTreeChangeListenerPath());
  74
  75         // Notify the listener if notifications should be enabled or not
  76         // If this shard is the leader then it will enable notifications else
  77         // it will not
  78         dataChangeListenerPath.tell(new EnableNotification(true), getSelf());
  79
  80         // Now store a reference to the data change listener so it can be notified
  81         // at a later point if notifications should be enabled or disabled
  82         actors.add(dataChangeListenerPath);
  83
  84         DOMDataTreeChangeListener listener = new ForwardingDataTreeChangeListener(dataChangeListenerPath);
  85
  86         LOG.debug("{}: Registering for path {}", persistenceId(), message.getPath());
  87
  88         return getShard().getDataStore().registerTreeChangeListener(message.getPath(), listener);
  89     }
  90 }