opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/DataChangeListenerSupport.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 java.util.ArrayList;
  11 import java.util.List;
  12 import akka.actor.ActorRef;
  13 import akka.actor.ActorSelection;
  14 import org.opendaylight.controller.cluster.datastore.messages.EnableNotification;
  15 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  16 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListenerReply;
  17 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeListener;
  18 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  19 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  20 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  21 import org.slf4j.Logger;
  22 import org.slf4j.LoggerFactory;
  23
  24 final class DataChangeListenerSupport extends LeaderLocalDelegateFactory<RegisterChangeListener, ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>>> {
  25     private static final Logger LOG = LoggerFactory.getLogger(DataChangeListenerSupport.class);
  26     private final List<DelayedListenerRegistration> delayedListenerRegistrations = new ArrayList<>();
  27     private final List<ActorSelection> dataChangeListeners =  new ArrayList<>();
  28
  29     DataChangeListenerSupport(final Shard shard) {
  30         super(shard);
  31     }
  32
  33     @Override
  34     void onLeadershipChange(final boolean isLeader) {
  35         for (ActorSelection dataChangeListener : dataChangeListeners) {
  36             dataChangeListener.tell(new EnableNotification(isLeader), getSelf());
  37         }
  38
  39         if (isLeader) {
  40             for (DelayedListenerRegistration reg: delayedListenerRegistrations) {
  41                 if(!reg.isClosed()) {
  42                     reg.setDelegate(createDelegate(reg.getRegisterChangeListener()));
  43                 }
  44             }
  45
  46             delayedListenerRegistrations.clear();
  47         }
  48     }
  49
  50     @Override
  51     void onMessage(final RegisterChangeListener message, final boolean isLeader) {
  52
  53         LOG.debug("{}: registerDataChangeListener for {}, leader: {}", persistenceId(), message.getPath(), isLeader);
  54
  55         ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier,
  56                                                      NormalizedNode<?, ?>>> registration;
  57         if (isLeader) {
  58             registration = createDelegate(message);
  59         } else {
  60             LOG.debug("{}: Shard is not the leader - delaying registration", persistenceId());
  61
  62             DelayedListenerRegistration delayedReg = new DelayedListenerRegistration(message);
  63             delayedListenerRegistrations.add(delayedReg);
  64             registration = delayedReg;
  65         }
  66
  67         ActorRef listenerRegistration = createActor(DataChangeListenerRegistration.props(registration));
  68
  69         LOG.debug("{}: registerDataChangeListener sending reply, listenerRegistrationPath = {} ",
  70                 persistenceId(), listenerRegistration.path());
  71
  72         tellSender(new RegisterChangeListenerReply(listenerRegistration));
  73     }
  74
  75     @Override
  76     ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>> createDelegate(
  77             final RegisterChangeListener message) {
  78         ActorSelection dataChangeListenerPath = selectActor(message.getDataChangeListenerPath());
  79
  80         // Notify the listener if notifications should be enabled or not
  81         // If this shard is the leader then it will enable notifications else
  82         // it will not
  83         dataChangeListenerPath.tell(new EnableNotification(true), getSelf());
  84
  85         // Now store a reference to the data change listener so it can be notified
  86         // at a later point if notifications should be enabled or disabled
  87         dataChangeListeners.add(dataChangeListenerPath);
  88
  89         AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>> listener =
  90                 new DataChangeListenerProxy(dataChangeListenerPath);
  91
  92         LOG.debug("{}: Registering for path {}", persistenceId(), message.getPath());
  93
  94         return getShard().getDataStore().registerChangeListener(message.getPath(), listener,
  95                 message.getScope());
  96     }
  97 }