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     private final List<DelayedListenerRegistration> delayedRegisterOnAllListeners = new ArrayList<>();
  32
  33     DataChangeListenerSupport(final Shard shard) {
  34         super(shard);
  35     }
  36
  37     @Override
  38     void onLeadershipChange(final boolean isLeader, boolean hasLeader) {
  39         LOG.debug("onLeadershipChange, isLeader: {}, hasLeader : {}", isLeader, hasLeader);
  40
  41         for (ActorSelection dataChangeListener : dataChangeListeners) {
  42             dataChangeListener.tell(new EnableNotification(isLeader), getSelf());
  43         }
  44
  45         if(hasLeader) {
  46             for (DelayedListenerRegistration reg : delayedRegisterOnAllListeners) {
  47                 registerDelayedListeners(reg);
  48             }
  49             delayedRegisterOnAllListeners.clear();
  50         }
  51
  52         if (isLeader) {
  53             for (DelayedListenerRegistration reg: delayedListenerRegistrations) {
  54                 registerDelayedListeners(reg);
  55             }
  56
  57             delayedListenerRegistrations.clear();
  58         }
  59     }
  60
  61     private void registerDelayedListeners(DelayedListenerRegistration reg) {
  62         if(!reg.isClosed()) {
  63             final Entry<ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>>, DOMImmutableDataChangeEvent> res =
  64                 createDelegate(reg.getRegisterChangeListener());
  65             reg.setDelegate(res.getKey());
  66             if (res.getValue() != null) {
  67                 reg.getInstance().onDataChanged(res.getValue());
  68             }
  69         }
  70     }
  71
  72     @Override
  73     void onMessage(final RegisterChangeListener message, final boolean isLeader, boolean hasLeader) {
  74
  75         LOG.debug("{}: registerDataChangeListener for {}, isLeader: {}, hasLeader : {}",
  76             persistenceId(), message.getPath(), isLeader, hasLeader);
  77
  78         final ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier,
  79                                                      NormalizedNode<?, ?>>> registration;
  80         final AsyncDataChangeEvent<YangInstanceIdentifier, NormalizedNode<?, ?>> event;
  81         if ((hasLeader && message.isRegisterOnAllInstances()) || isLeader) {
  82             final Entry<ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>>, DOMImmutableDataChangeEvent> res =
  83                     createDelegate(message);
  84             registration = res.getKey();
  85             event = res.getValue();
  86         } else {
  87             LOG.debug("{}: Shard is not the leader - delaying registration", persistenceId());
  88
  89             DelayedListenerRegistration delayedReg = new DelayedListenerRegistration(message);
  90             if(message.isRegisterOnAllInstances()) {
  91                 delayedRegisterOnAllListeners.add(delayedReg);
  92             } else {
  93                 delayedListenerRegistrations.add(delayedReg);
  94             }
  95             registration = delayedReg;
  96             event = null;
  97         }
  98
  99         ActorRef listenerRegistration = createActor(DataChangeListenerRegistration.props(registration));
 100
 101         LOG.debug("{}: registerDataChangeListener sending reply, listenerRegistrationPath = {} ",
 102                 persistenceId(), listenerRegistration.path());
 103
 104         tellSender(new RegisterChangeListenerReply(listenerRegistration));
 105         if (event != null) {
 106             registration.getInstance().onDataChanged(event);
 107         }
 108     }
 109
 110     @Override
 111     Entry<ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>>, DOMImmutableDataChangeEvent> createDelegate(
 112             final RegisterChangeListener message) {
 113         ActorSelection dataChangeListenerPath = selectActor(message.getDataChangeListenerPath());
 114
 115         // Notify the listener if notifications should be enabled or not
 116         // If this shard is the leader then it will enable notifications else
 117         // it will not
 118         dataChangeListenerPath.tell(new EnableNotification(true), getSelf());
 119
 120         // Now store a reference to the data change listener so it can be notified
 121         // at a later point if notifications should be enabled or disabled
 122         if(!message.isRegisterOnAllInstances()) {
 123             dataChangeListeners.add(dataChangeListenerPath);
 124         }
 125
 126         AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>> listener =
 127                 new DataChangeListenerProxy(dataChangeListenerPath);
 128
 129         LOG.debug("{}: Registering for path {}", persistenceId(), message.getPath());
 130
 131         return getShard().getDataStore().registerChangeListener(message.getPath(), listener,
 132                 message.getScope());
 133     }
 134 }