Added an initial sketch of a distributed cluster store.

@@ -14,6 +14,12 @@ public class DefaultControllerNode implements ControllerNode {
     private final NodeId id;
     private final IpPrefix ip;
 
+    // For serialization
+    private DefaultControllerNode() {
+        this.id = null;
+        this.ip = null;
+    }
+
     /**
      * Creates a new instance with the specified id and IP address.
      *

+package org.onlab.onos.store.cluster.impl;
+
+import com.google.common.collect.ImmutableSet;
+import com.hazelcast.core.HazelcastInstance;
+import com.hazelcast.core.Member;
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.onos.cluster.ClusterStore;
+import org.onlab.onos.cluster.ControllerNode;
+import org.onlab.onos.cluster.DefaultControllerNode;
+import org.onlab.onos.cluster.NodeId;
+import org.onlab.onos.store.StoreService;
+import org.onlab.packet.IpPrefix;
+import org.slf4j.Logger;
+
+import java.util.Set;
+
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Distributed implementation of the cluster nodes store.
+ */
+@Component(immediate = true)
+@Service
+public class DistributedClusterStore implements ClusterStore {
+
+    private final Logger log = getLogger(getClass());
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected StoreService storeService;
+
+    private HazelcastInstance theInstance;
+
+    // FIXME: experimental implementation; enhance to assure persistence and
+    // visibility to nodes that are not currently in the cluster
+
+    @Activate
+    public void activate() {
+        log.info("Started");
+        theInstance = storeService.getHazelcastInstance();
+
+    }
+
+    @Deactivate
+    public void deactivate() {
+        log.info("Stopped");
+    }
+
+    @Override
+    public ControllerNode getLocalNode() {
+        return node(theInstance.getCluster().getLocalMember());
+    }
+
+    @Override
+    public Set<ControllerNode> getNodes() {
+        ImmutableSet.Builder<ControllerNode> builder = ImmutableSet.builder();
+        for (Member member : theInstance.getCluster().getMembers()) {
+            builder.add(node(member));
+        }
+        return builder.build();
+    }
+
+    @Override
+    public ControllerNode getNode(NodeId nodeId) {
+        for (Member member : theInstance.getCluster().getMembers()) {
+            if (member.getUuid().equals(nodeId.toString())) {
+                return node(member);
+            }
+        }
+        return null;
+    }
+
+    @Override
+    public ControllerNode.State getState(NodeId nodeId) {
+        return ControllerNode.State.ACTIVE;
+    }
+
+    // Creates a controller node descriptor from the Hazelcast member.
+    private ControllerNode node(Member member) {
+        return new DefaultControllerNode(new NodeId(member.getUuid()),
+                                         IpPrefix.valueOf(member.getSocketAddress().getAddress().getAddress()));
+    }
+}