opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/DataTreeChangeListenerProxy.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 akka.actor.PoisonPill;
  13 import akka.dispatch.OnComplete;
  14 import com.google.common.base.Preconditions;
  15 import javax.annotation.concurrent.GuardedBy;
  16 import org.opendaylight.controller.cluster.datastore.exceptions.LocalShardNotFoundException;
  17 import org.opendaylight.controller.cluster.datastore.messages.CloseDataTreeChangeListenerRegistration;
  18 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListener;
  19 import org.opendaylight.controller.cluster.datastore.messages.RegisterDataTreeChangeListenerReply;
  20 import org.opendaylight.controller.cluster.datastore.utils.ActorContext;
  21 import org.opendaylight.controller.md.sal.dom.api.DOMDataTreeChangeListener;
  22 import org.opendaylight.yangtools.concepts.AbstractListenerRegistration;
  23 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
  24 import org.slf4j.Logger;
  25 import org.slf4j.LoggerFactory;
  26 import scala.concurrent.Future;
  27
  28 /**
  29  * Proxy class for holding required state to lazily instantiate a listener registration with an
  30  * asynchronously-discovered actor.
  31  *
  32  * @param <T> listener type
  33  */
  34 final class DataTreeChangeListenerProxy<T extends DOMDataTreeChangeListener> extends AbstractListenerRegistration<T> {
  35     private static final Logger LOG = LoggerFactory.getLogger(DataTreeChangeListenerProxy.class);
  36     private final ActorRef dataChangeListenerActor;
  37     private final ActorContext actorContext;
  38
  39     @GuardedBy("this")
  40     private ActorSelection listenerRegistrationActor;
  41
  42     public DataTreeChangeListenerProxy(final ActorContext actorContext, final T listener) {
  43         super(listener);
  44         this.actorContext = Preconditions.checkNotNull(actorContext);
  45         this.dataChangeListenerActor = actorContext.getActorSystem().actorOf(
  46             DataTreeChangeListenerActor.props(getInstance()).withDispatcher(actorContext.getNotificationDispatcherPath()));
  47     }
  48
  49     @Override
  50     protected synchronized void removeRegistration() {
  51         if (listenerRegistrationActor != null) {
  52             listenerRegistrationActor.tell(CloseDataTreeChangeListenerRegistration.getInstance(), ActorRef.noSender());
  53             listenerRegistrationActor = null;
  54         }
  55
  56         dataChangeListenerActor.tell(PoisonPill.getInstance(), ActorRef.noSender());
  57     }
  58
  59     void init(final String shardName, final YangInstanceIdentifier treeId) {
  60         Future<ActorRef> findFuture = actorContext.findLocalShardAsync(shardName);
  61         findFuture.onComplete(new OnComplete<ActorRef>() {
  62             @Override
  63             public void onComplete(final Throwable failure, final ActorRef shard) {
  64                 if (failure instanceof LocalShardNotFoundException) {
  65                     LOG.debug("No local shard found for {} - DataTreeChangeListener {} at path {} " +
  66                             "cannot be registered", shardName, getInstance(), treeId);
  67                 } else if (failure != null) {
  68                     LOG.error("Failed to find local shard {} - DataTreeChangeListener {} at path {} " +
  69                             "cannot be registered: {}", shardName, getInstance(), treeId, failure);
  70                 } else {
  71                     doRegistration(shard, treeId);
  72                 }
  73             }
  74         }, actorContext.getClientDispatcher());
  75     }
  76
  77     private void setListenerRegistrationActor(final ActorSelection actor) {
  78         if (actor == null) {
  79             LOG.debug("Ignoring null actor on {}", this);
  80             return;
  81         }
  82
  83         synchronized (this) {
  84             if (!isClosed()) {
  85                 this.listenerRegistrationActor = actor;
  86                 return;
  87             }
  88         }
  89
  90         // This registration has already been closed, notify the actor
  91         actor.tell(CloseDataTreeChangeListenerRegistration.getInstance(), null);
  92     }
  93
  94     private void doRegistration(final ActorRef shard, final YangInstanceIdentifier path) {
  95
  96         Future<Object> future = actorContext.executeOperationAsync(shard,
  97                 new RegisterDataTreeChangeListener(path, dataChangeListenerActor),
  98                 actorContext.getDatastoreContext().getShardInitializationTimeout());
  99
 100         future.onComplete(new OnComplete<Object>(){
 101             @Override
 102             public void onComplete(final Throwable failure, final Object result) {
 103                 if (failure != null) {
 104                     LOG.error("Failed to register DataTreeChangeListener {} at path {}",
 105                             getInstance(), path.toString(), failure);
 106                 } else {
 107                     RegisterDataTreeChangeListenerReply reply = (RegisterDataTreeChangeListenerReply) result;
 108                     setListenerRegistrationActor(actorContext.actorSelection(
 109                             reply.getListenerRegistrationPath().path()));
 110                 }
 111             }
 112         }, actorContext.getClientDispatcher());
 113     }
 114 }