Added API for the (new) Leadership Service. For now there is a single
Leader elected for all purposes.
In the future the leader could be per topic.
Change-Id: I6d4f997b40bfdaa6fa9a5547e7641bf62c9d3ddb
diff --git a/core/api/src/main/java/org/onlab/onos/cluster/LeadershipEvent.java b/core/api/src/main/java/org/onlab/onos/cluster/LeadershipEvent.java
new file mode 100644
index 0000000..c285eba
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/cluster/LeadershipEvent.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.onos.cluster;
+
+import org.onlab.onos.event.AbstractEvent;
+
+/**
+ * Describes leadership-related event.
+ */
+public class LeadershipEvent extends AbstractEvent<LeadershipEvent.Type, ControllerNode> {
+
+ /**
+ * Type of leadership-related events.
+ */
+ public enum Type {
+ /**
+ * Signifies that the leader has changed. The event subject is the
+ * new leader.
+ */
+ LEADER_CHANGED
+ }
+
+ /**
+ * Creates an event of a given type and for the specified instance and the
+ * current time.
+ *
+ * @param type leadership event type
+ * @param instance cluster device subject
+ */
+ public LeadershipEvent(Type type, ControllerNode instance) {
+ super(type, instance);
+ }
+
+ /**
+ * Creates an event of a given type and for the specified device and time.
+ *
+ * @param type device event type
+ * @param instance event device subject
+ * @param time occurrence time
+ */
+ public LeadershipEvent(Type type, ControllerNode instance, long time) {
+ super(type, instance, time);
+ }
+
+}
diff --git a/core/api/src/main/java/org/onlab/onos/cluster/LeadershipEventListener.java b/core/api/src/main/java/org/onlab/onos/cluster/LeadershipEventListener.java
new file mode 100644
index 0000000..5de5596
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/cluster/LeadershipEventListener.java
@@ -0,0 +1,24 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.onos.cluster;
+
+import org.onlab.onos.event.EventListener;
+
+/**
+ * Entity capable of receiving device leadership-related events.
+ */
+public interface LeadershipEventListener extends EventListener<LeadershipEvent> {
+}
diff --git a/core/api/src/main/java/org/onlab/onos/cluster/LeadershipService.java b/core/api/src/main/java/org/onlab/onos/cluster/LeadershipService.java
new file mode 100644
index 0000000..240fb46
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/cluster/LeadershipService.java
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2014 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.onlab.onos.cluster;
+
+/**
+ * Service for obtaining information about the leader election.
+ */
+public interface LeadershipService {
+
+ /**
+ * Returns the current leader controller node.
+ *
+ * @return current leader controller node
+ */
+ ControllerNode getLeader();
+
+ /**
+ * Adds the specified leadership event listener.
+ *
+ * @param listener the leadership listener
+ */
+ void addListener(LeadershipEventListener listener);
+
+ /**
+ * Removes the specified leadership event listener.
+ *
+ * @param listener the leadership listener
+ */
+ void removeListener(LeadershipEventListener listener);
+
+}