Added couple of methods to LeadershipService.

Change-Id: I259b1a282a51af9425e941a720336f89d66f1097

@@ -16,6 +16,7 @@
 package org.onosproject.cluster;
 
 import java.util.Map;
+import java.util.Set;
 
 /**
  * Service for leader election.
@@ -27,13 +28,27 @@ import java.util.Map;
 public interface LeadershipService {
 
     /**
-     * Gets the most recent leader for the topic.
+     * Returns the current leader for the topic.
      * @param path topic
      * @return nodeId of the leader, null if so such topic exists.
      */
     NodeId getLeader(String path);
 
     /**
+     * Returns the current leadership info for the topic.
+     * @param path topic
+     * @return leadership info or null if so such topic exists.
+     */
+    Leadership getLeadership(String path);
+
+    /**
+     * Returns the set of topics owned by the specified node.
+     * @param nodeId node Id.
+     * @return set of topics for which this node is the current leader.
+     */
+    Set<String> ownedTopics(NodeId nodeId);
+
+    /**
      * Joins the leadership contest.
      * @param path topic for which this controller node wishes to be a leader.
      */
@@ -45,6 +60,10 @@ public interface LeadershipService {
      */
     void withdraw(String path);
 
+    /**
+     * Returns the current leader board.
+     * @return mapping from topic to leadership info.
+     */
     Map<String, Leadership> getLeaderBoard();
 
     /**

@@ -46,10 +46,12 @@ import org.slf4j.LoggerFactory;
 
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
 import java.util.concurrent.locks.Lock;
+import java.util.stream.Collectors;
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static org.onlab.util.Tools.groupedThreads;
@@ -162,6 +164,28 @@ public class HazelcastLeadershipService implements LeadershipService {
     }
 
     @Override
+    public Leadership getLeadership(String path) {
+        checkArgument(path != null);
+        Topic topic = topics.get(path);
+        if (topic != null) {
+            return new Leadership(topic.topicName(),
+                    topic.leader(),
+                    topic.term());
+        }
+        return null;
+    }
+
+    @Override
+    public Set<String> ownedTopics(NodeId nodeId) {
+        checkArgument(nodeId != null);
+        return topics.values()
+                .stream()
+                .filter(topic -> nodeId.equals(topic.leader()))
+                .map(topic -> topic.topicName)
+                .collect(Collectors.toSet());
+    }
+
+    @Override
     public void runForLeadership(String path) {
         checkArgument(path != null);
         Topic topic = new Topic(path);

@@ -2,6 +2,7 @@ package org.onosproject.store.consistent.impl;
 
 import static org.onlab.util.Tools.groupedThreads;
 import static org.slf4j.LoggerFactory.getLogger;
+import static com.google.common.base.Preconditions.checkArgument;
 
 import java.util.Map;
 import java.util.Map.Entry;
@@ -10,6 +11,7 @@ import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
 
 import org.apache.felix.scr.annotations.Activate;
 import org.apache.felix.scr.annotations.Component;
@@ -171,6 +173,22 @@ public class DistributedLeadershipManager implements LeadershipService {
     }
 
     @Override
+    public Leadership getLeadership(String path) {
+        checkArgument(path != null);
+        return leaderBoard.get(path);
+    }
+
+    @Override
+    public Set<String> ownedTopics(NodeId nodeId) {
+        checkArgument(nodeId != null);
+        return leaderBoard.entrySet()
+                    .stream()
+                    .filter(entry -> nodeId.equals(entry.getValue().leader()))
+                    .map(Entry::getKey)
+                    .collect(Collectors.toSet());
+    }
+
+    @Override
     public void runForLeadership(String path) {
         log.info("Running for leadership for topic: {}", path);
         activeTopics.add(path);

@@ -15,10 +15,14 @@
  */
 package org.onosproject.store.trivial.impl;
 
+import static com.google.common.base.Preconditions.checkArgument;
+
 import java.util.Map;
+import java.util.Map.Entry;
 import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.CopyOnWriteArraySet;
+import java.util.stream.Collectors;
 
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.Reference;
@@ -55,6 +59,22 @@ public class SimpleLeadershipManager implements LeadershipService {
     }
 
     @Override
+    public Leadership getLeadership(String path) {
+        checkArgument(path != null);
+        return elections.get(path) ? new Leadership(path, clusterService.getLocalNode().id(), 0) : null;
+    }
+
+    @Override
+    public Set<String> ownedTopics(NodeId nodeId) {
+        checkArgument(nodeId != null);
+        return elections.entrySet()
+                .stream()
+                .filter(Entry::getValue)
+                .map(Entry::getKey)
+                .collect(Collectors.toSet());
+    }
+
+    @Override
     public void runForLeadership(String path) {
         elections.put(path, true);
         for (LeadershipEventListener listener : listeners) {
@@ -88,5 +108,4 @@ public class SimpleLeadershipManager implements LeadershipService {
     public void removeListener(LeadershipEventListener listener) {
         listeners.remove(listener);
     }
-
 }