CDS: Move DataChangeListener into a support class

[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / main / java / org / opendaylight / controller / cluster / datastore / DataChangeListenerSupport.java

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/DataChangeListenerSupport.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/DataChangeListenerSupport.java
new file mode 100644 (file)
index 0000000..7a033cf
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+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/DataChangeListenerSupport.java
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2015 Cisco Systems, Inc. and others.  All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v1.0 which accompanies this distribution,
+ * and is available at http://www.eclipse.org/legal/epl-v10.html
+ */
+package org.opendaylight.controller.cluster.datastore;
+
+import com.google.common.base.Preconditions;
+import java.util.ArrayList;
+import java.util.List;
+import akka.actor.ActorRef;
+import akka.actor.ActorSelection;
+import org.opendaylight.controller.cluster.datastore.messages.EnableNotification;
+import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListener;
+import org.opendaylight.controller.cluster.datastore.messages.RegisterChangeListenerReply;
+import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeListener;
+import org.opendaylight.yangtools.concepts.ListenerRegistration;
+import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+final class DataChangeListenerSupport extends LeaderLocalDelegateFactory<RegisterChangeListener, ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>>> {
+    private static final Logger LOG = LoggerFactory.getLogger(DataChangeListenerSupport.class);
+    private final List<DelayedListenerRegistration> delayedListenerRegistrations = new ArrayList<>();
+    private final List<ActorSelection> dataChangeListeners =  new ArrayList<>();
+    private final Shard shard;
+
+    DataChangeListenerSupport(final Shard shard) {
+        this.shard = Preconditions.checkNotNull(shard);
+    }
+
+    @Override
+    void onLeadershipChange(final boolean isLeader) {
+        for (ActorSelection dataChangeListener : dataChangeListeners) {
+            dataChangeListener.tell(new EnableNotification(isLeader), shard.getSelf());
+        }
+
+        if (isLeader) {
+            for (DelayedListenerRegistration reg: delayedListenerRegistrations) {
+                if(!reg.isClosed()) {
+                    reg.setDelegate(createDelegate(reg.getRegisterChangeListener()));
+                }
+            }
+
+            delayedListenerRegistrations.clear();
+        }
+    }
+
+    @Override
+    void onMessage(final RegisterChangeListener message, final boolean isLeader) {
+
+        LOG.debug("{}: registerDataChangeListener for {}, leader: {}", shard.persistenceId(), message.getPath(), isLeader);
+
+        ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier,
+                                                     NormalizedNode<?, ?>>> registration;
+        if (isLeader) {
+            registration = createDelegate(message);
+        } else {
+            LOG.debug("{}: Shard is not the leader - delaying registration", shard.persistenceId());
+
+            DelayedListenerRegistration delayedReg = new DelayedListenerRegistration(message);
+            delayedListenerRegistrations.add(delayedReg);
+            registration = delayedReg;
+        }
+
+        ActorRef listenerRegistration = shard.getContext().actorOf(
+                DataChangeListenerRegistration.props(registration));
+
+        LOG.debug("{}: registerDataChangeListener sending reply, listenerRegistrationPath = {} ",
+                shard.persistenceId(), listenerRegistration.path());
+
+        shard.getSender().tell(new RegisterChangeListenerReply(listenerRegistration), shard.getSelf());
+    }
+
+    @Override
+    ListenerRegistration<AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>>> createDelegate(
+            final RegisterChangeListener message) {
+        ActorSelection dataChangeListenerPath = shard.getContext().system().actorSelection(
+                message.getDataChangeListenerPath());
+
+        // Notify the listener if notifications should be enabled or not
+        // If this shard is the leader then it will enable notifications else
+        // it will not
+        dataChangeListenerPath.tell(new EnableNotification(true), shard.getSelf());
+
+        // Now store a reference to the data change listener so it can be notified
+        // at a later point if notifications should be enabled or disabled
+        dataChangeListeners.add(dataChangeListenerPath);
+
+        AsyncDataChangeListener<YangInstanceIdentifier, NormalizedNode<?, ?>> listener =
+                new DataChangeListenerProxy(dataChangeListenerPath);
+
+        LOG.debug("{}: Registering for path {}", shard.persistenceId(), message.getPath());
+
+        return shard.getDataStore().registerChangeListener(message.getPath(), listener,
+                message.getScope());
+    }
+}