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 akka.actor.ActorRef;
  11 import akka.actor.ActorSelection;
  12 import java.util.ArrayList;
  13 import java.util.List;
  14 import java.util.Map.Entry;
  15 import org.opendaylight.controller.cluster.datastore.messages.EnableNotification;
  16 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
  17 import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListenerReply;
  18 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeEvent;
  19 import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeListener;
  20 import org.opendaylight.controller.md.sal.dom.store.impl.DOMImmutableDataChangeEvent;
  21 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  22 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  23 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
  24 import org.slf4j.Logger;
  25 import org.slf4j.LoggerFactory;
  26
  27 final class DataChangeListenerSupport extends LeaderLocalDelegateFactory<RegisterChangeListener, ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>>, DOMImmutableDataChangeEvent> {
  28     private static final Logger LOG = LoggerFactory.getLogger(DataChangeListenerSupport.class);
  29     private final List<DelayedListenerRegistration> delayedListenerRegistrations = new ArrayList<>();
  30     private final List<ActorSelection> dataChangeListeners =  new ArrayList<>();
  31
  32     DataChangeListenerSupport(final Shard shard) {
  33         super(shard);
  34     }
  35
  36     @Override
  37     void onLeadershipChange(final boolean isLeader) {
  38         for (ActorSelection dataChangeListener : dataChangeListeners) {
  39             dataChangeListener.tell(new EnableNotification(isLeader), getSelf());
  40         }
  41
  42         if (isLeader) {
  43             for (DelayedListenerRegistration reg: delayedListenerRegistrations) {
  44                 if(!reg.isClosed()) {
  45                     final Entry<ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>>, DOMImmutableDataChangeEvent> res =
  46                             createDelegate(reg.getRegisterChangeListener());
  47                     reg.setDelegate(res.getKey());
  48                     if (res.getValue() != null) {
  49                         reg.getInstance().onDataChanged(res.getValue());
  50                     }
  51                 }
  52             }
  53
  54             delayedListenerRegistrations.clear();
  55         }
  56     }
  57
  58     @Override
  59     void onMessage(final RegisterChangeListener message, final boolean isLeader) {
  60
  61         LOG.debug("{}: registerDataChangeListener for {}, leader: {}", persistenceId(), message.getPath(), isLeader);
  62
  63         final ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier,
  64                                                      NormalizedNode<?, ?>>> registration;
  65         final AsyncDataChangeEvent<YangInstanceIdentifier, NormalizedNode<?, ?>> event;
  66         if (isLeader) {
  67             final Entry<ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>>, DOMImmutableDataChangeEvent> res =
  68                     createDelegate(message);
  69             registration = res.getKey();
  70             event = res.getValue();
  71         } else {
  72             LOG.debug("{}: Shard is not the leader - delaying registration", persistenceId());
  73
  74             DelayedListenerRegistration delayedReg = new DelayedListenerRegistration(message);
  75             delayedListenerRegistrations.add(delayedReg);
  76             registration = delayedReg;
  77             event = null;
  78         }
  79
  80         ActorRef listenerRegistration = createActor(DataChangeListenerRegistration.props(registration));
  81
  82         LOG.debug("{}: registerDataChangeListener sending reply, listenerRegistrationPath = {} ",
  83                 persistenceId(), listenerRegistration.path());
  84
  85         tellSender(new RegisterChangeListenerReply(listenerRegistration));
  86         if (event != null) {
  87             registration.getInstance().onDataChanged(event);
  88         }
  89     }
  90
  91     @Override
  92     Entry<ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>>, DOMImmutableDataChangeEvent> createDelegate(
  93             final RegisterChangeListener message) {
  94         ActorSelection dataChangeListenerPath = selectActor(message.getDataChangeListenerPath());
  95
  96         // Notify the listener if notifications should be enabled or not
  97         // If this shard is the leader then it will enable notifications else
  98         // it will not
  99         dataChangeListenerPath.tell(new EnableNotification(true), getSelf());
 100
 101         // Now store a reference to the data change listener so it can be notified
 102         // at a later point if notifications should be enabled or disabled
 103         dataChangeListeners.add(dataChangeListenerPath);
 104
 105         AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>> listener =
 106                 new DataChangeListenerProxy(dataChangeListenerPath);
 107
 108         LOG.debug("{}: Registering for path {}", persistenceId(), message.getPath());
 109
 110         return getShard().getDataStore().registerChangeListener(message.getPath(), listener,
 111                 message.getScope());
 112     }
 113 }