Bug 7407 - CDS: allow applications to request Leader movement

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

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/sharding/RoleChangeListenerActor.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/sharding/RoleChangeListenerActor.java
new file mode 100644 (file)
index 0000000..38b69e7
--- /dev/null
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/sharding/RoleChangeListenerActor.java
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2017 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.sharding;
+
+import akka.actor.ActorRef;
+import akka.actor.Props;
+import com.google.common.base.Preconditions;
+import org.opendaylight.controller.cluster.common.actor.AbstractUntypedActor;
+import org.opendaylight.controller.cluster.dom.api.LeaderLocation;
+import org.opendaylight.controller.cluster.dom.api.LeaderLocationListener;
+import org.opendaylight.controller.cluster.notifications.LeaderStateChanged;
+import org.opendaylight.controller.cluster.notifications.RegisterRoleChangeListener;
+import org.opendaylight.controller.cluster.notifications.RoleChangeNotification;
+
+/**
+ * Proxy actor which acts as a facade for user-provided
+ * {@link LeaderLocationListener}. It subscribes for {@link LeaderStateChanged}
+ * notifications in its pre start hook and translates them to
+ * {@link LeaderLocationListener#onLeaderLocationChanged(LeaderLocation)}
+ * events.
+ */
+public class RoleChangeListenerActor extends AbstractUntypedActor {
+    private final LeaderLocationListener leaderLocationListener;
+    private final ActorRef roleChangeNotifier;
+
+    private RoleChangeListenerActor(final ActorRef roleChangeNotifier, final LeaderLocationListener listener) {
+        this.roleChangeNotifier = Preconditions.checkNotNull(roleChangeNotifier);
+        this.leaderLocationListener = Preconditions.checkNotNull(listener);
+    }
+
+    @Override
+    public void preStart() throws Exception {
+        super.preStart();
+        roleChangeNotifier.tell(new RegisterRoleChangeListener(), getSelf());
+    }
+
+    @Override
+    protected void handleReceive(final Object message) throws Exception {
+        if (message instanceof RoleChangeNotification) {
+            ignoreMessage(message);
+        } else if (message instanceof LeaderStateChanged) {
+            onLeaderStateChanged((LeaderStateChanged) message);
+        } else {
+            unknownMessage(message);
+        }
+    }
+
+    private void onLeaderStateChanged(final LeaderStateChanged message) {
+        final LeaderLocation newLocation;
+        if (message.getLeaderId() == null) {
+            newLocation = LeaderLocation.UNKNOWN;
+        } else if (message.getMemberId().equals(message.getLeaderId())) {
+            newLocation = LeaderLocation.LOCAL;
+        } else {
+            newLocation = LeaderLocation.REMOTE;
+        }
+
+        // TODO should we wrap this in try catch block?
+        leaderLocationListener.onLeaderLocationChanged(newLocation);
+    }
+
+    public static Props props(final ActorRef roleChangeNotifier, final LeaderLocationListener listener) {
+        return Props.create(RoleChangeListenerActor.class, roleChangeNotifier, listener);
+    }
+}