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 java.util.Collections;
  15 import java.util.Map.Entry;
  16 import org.opendaylight.controller.cluster.datastore.messages.EnableNotification;
  17 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  18 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListenerReply;
  19 import org.opendaylight.controller.md.sal.dom.api.DOMDataTreeChangeListener;
  20 import org.opendaylight.yangtools.concepts.ListenerRegistration;
  21 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  22 import org.slf4j.Logger;
  23 import org.slf4j.LoggerFactory;
  24
  25 final class DataTreeChangeListenerSupport extends LeaderLocalDelegateFactory<RegisterDataTreeChangeListener, ListenerRegistration<DOMDataTreeChangeListener>, DataTreeCandidate> {
  26     private static final Logger LOG = LoggerFactory.getLogger(DataTreeChangeListenerSupport.class);
  27     private final ArrayList<DelayedDataTreeListenerRegistration> delayedRegistrations = new ArrayList<>();
  28     private final Collection<ActorSelection> actors = new ArrayList<>();
  29
  30     DataTreeChangeListenerSupport(final Shard shard) {
  31         super(shard);
  32     }
  33
  34     @Override
  35     void onLeadershipChange(final boolean isLeader) {
  36         if (isLeader) {
  37             for (DelayedDataTreeListenerRegistration reg : delayedRegistrations) {
  38                 reg.createDelegate(this);
  39             }
  40             delayedRegistrations.clear();
  41             delayedRegistrations.trimToSize();
  42         }
  43
  44         final EnableNotification msg = new EnableNotification(isLeader);
  45         for (ActorSelection dataChangeListener : actors) {
  46             dataChangeListener.tell(msg, getSelf());
  47         }
  48     }
  49
  50     @Override
  51     void onMessage(final RegisterDataTreeChangeListener registerTreeChangeListener, final boolean isLeader) {
  52         LOG.debug("{}: registerTreeChangeListener for {}, leader: {}", persistenceId(), registerTreeChangeListener.getPath(), isLeader);
  53
  54         final ListenerRegistration<DOMDataTreeChangeListener> registration;
  55         final DataTreeCandidate event;
  56         if (!isLeader) {
  57             LOG.debug("{}: Shard is not the leader - delaying registration", persistenceId());
  58
  59             DelayedDataTreeListenerRegistration delayedReg =
  60                     new DelayedDataTreeListenerRegistration(registerTreeChangeListener);
  61             delayedRegistrations.add(delayedReg);
  62             registration = delayedReg;
  63             event = null;
  64         } else {
  65             final Entry<ListenerRegistration<DOMDataTreeChangeListener>, DataTreeCandidate> res = createDelegate(registerTreeChangeListener);
  66             registration = res.getKey();
  67             event = res.getValue();
  68         }
  69
  70         ActorRef listenerRegistration = createActor(DataTreeChangeListenerRegistrationActor.props(registration));
  71
  72         LOG.debug("{}: registerDataChangeListener sending reply, listenerRegistrationPath = {} ",
  73             persistenceId(), listenerRegistration.path());
  74
  75         tellSender(new RegisterDataTreeChangeListenerReply(listenerRegistration));
  76         if (event != null) {
  77             registration.getInstance().onDataTreeChanged(Collections.singletonList(event));
  78         }
  79     }
  80
  81     @Override
  82     Entry<ListenerRegistration<DOMDataTreeChangeListener>, DataTreeCandidate> createDelegate(final RegisterDataTreeChangeListener message) {
  83         ActorSelection dataChangeListenerPath = selectActor(message.getDataTreeChangeListenerPath());
  84
  85         // Notify the listener if notifications should be enabled or not
  86         // If this shard is the leader then it will enable notifications else
  87         // it will not
  88         dataChangeListenerPath.tell(new EnableNotification(true), getSelf());
  89
  90         // Now store a reference to the data change listener so it can be notified
  91         // at a later point if notifications should be enabled or disabled
  92         actors.add(dataChangeListenerPath);
  93
  94         DOMDataTreeChangeListener listener = new ForwardingDataTreeChangeListener(dataChangeListenerPath);
  95
  96         LOG.debug("{}: Registering for path {}", persistenceId(), message.getPath());
  97
  98         return getShard().getDataStore().registerTreeChangeListener(message.getPath(), listener);
  99     }
 100 }