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 com.google.common.base.Optional;
  13 import java.util.ArrayList;
  14 import java.util.Collection;
  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,
  26         ListenerRegistration<DOMDataTreeChangeListener>, Optional<DataTreeCandidate>> {
  27     private static final Logger LOG = LoggerFactory.getLogger(DataTreeChangeListenerSupport.class);
  28     private final ArrayList<DelayedDataTreeListenerRegistration> delayedRegistrations = new ArrayList<>();
  29     private final Collection<ActorSelection> actors = new ArrayList<>();
  30
  31     DataTreeChangeListenerSupport(final Shard shard) {
  32         super(shard);
  33     }
  34
  35     @Override
  36     void onLeadershipChange(final boolean isLeader, boolean hasLeader) {
  37         final EnableNotification msg = new EnableNotification(isLeader);
  38         for (ActorSelection dataChangeListener : actors) {
  39             dataChangeListener.tell(msg, getSelf());
  40         }
  41
  42         if (isLeader) {
  43             for (DelayedDataTreeListenerRegistration reg : delayedRegistrations) {
  44                 reg.createDelegate(this);
  45             }
  46             delayedRegistrations.clear();
  47             delayedRegistrations.trimToSize();
  48         }
  49     }
  50
  51     @Override
  52     void onMessage(final RegisterDataTreeChangeListener registerTreeChangeListener, final boolean isLeader, boolean hasLeader) {
  53         LOG.debug("{}: registerTreeChangeListener for {}, leader: {}", persistenceId(), registerTreeChangeListener.getPath(), isLeader);
  54
  55         final ListenerRegistration<DOMDataTreeChangeListener> registration;
  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         } else {
  64             final Entry<ListenerRegistration<DOMDataTreeChangeListener>, Optional<DataTreeCandidate>> res =
  65                     createDelegate(registerTreeChangeListener);
  66             registration = res.getKey();
  67             getShard().getDataStore().notifyOfInitialData(registerTreeChangeListener.getPath(),
  68                     registration.getInstance(), res.getValue());
  69         }
  70
  71         ActorRef listenerRegistration = createActor(DataTreeChangeListenerRegistrationActor.props(registration));
  72
  73         LOG.debug("{}: registerDataChangeListener sending reply, listenerRegistrationPath = {} ",
  74             persistenceId(), listenerRegistration.path());
  75
  76         tellSender(new RegisterDataTreeChangeListenerReply(listenerRegistration));
  77     }
  78
  79     @Override
  80     Entry<ListenerRegistration<DOMDataTreeChangeListener>, Optional<DataTreeCandidate>> createDelegate(final RegisterDataTreeChangeListener message) {
  81         ActorSelection dataChangeListenerPath = selectActor(message.getDataTreeChangeListenerPath());
  82
  83         // Notify the listener if notifications should be enabled or not
  84         // If this shard is the leader then it will enable notifications else
  85         // it will not
  86         dataChangeListenerPath.tell(new EnableNotification(true), getSelf());
  87
  88         // Now store a reference to the data change listener so it can be notified
  89         // at a later point if notifications should be enabled or disabled
  90         actors.add(dataChangeListenerPath);
  91
  92         DOMDataTreeChangeListener listener = new ForwardingDataTreeChangeListener(dataChangeListenerPath);
  93
  94         LOG.debug("{}: Registering for path {}", persistenceId(), message.getPath());
  95
  96         return getShard().getDataStore().registerTreeChangeListener(message.getPath(), listener);
  97     }
  98 }