Renamed *Instance to *Node for better readability and to avoid conflict with notion of Karaf instance.
Added cluster service and trivial store implementations.
diff --git a/core/net/src/main/java/org/onlab/onos/cluster/impl/ClusterManager.java b/core/net/src/main/java/org/onlab/onos/cluster/impl/ClusterManager.java
new file mode 100644
index 0000000..43d743c
--- /dev/null
+++ b/core/net/src/main/java/org/onlab/onos/cluster/impl/ClusterManager.java
@@ -0,0 +1,86 @@
+package org.onlab.onos.cluster.impl;
+
+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.ClusterEvent;
+import org.onlab.onos.cluster.ClusterEventListener;
+import org.onlab.onos.cluster.ClusterService;
+import org.onlab.onos.cluster.ClusterStore;
+import org.onlab.onos.cluster.ControllerNode;
+import org.onlab.onos.cluster.NodeId;
+import org.onlab.onos.event.AbstractListenerRegistry;
+import org.onlab.onos.event.EventDeliveryService;
+import org.slf4j.Logger;
+
+import java.util.Set;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+import static org.slf4j.LoggerFactory.getLogger;
+
+/**
+ * Implementation of the cluster service.
+ */
+@Component(immediate = true)
+@Service
+public class ClusterManager implements ClusterService {
+
+ public static final String INSTANCE_ID_NULL = "Instance ID cannot be null";
+ private final Logger log = getLogger(getClass());
+
+ protected final AbstractListenerRegistry<ClusterEvent, ClusterEventListener>
+ listenerRegistry = new AbstractListenerRegistry<>();
+
+ @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+ protected ClusterStore store;
+
+ @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+ protected EventDeliveryService eventDispatcher;
+
+ @Activate
+ public void activate() {
+ eventDispatcher.addSink(ClusterEvent.class, listenerRegistry);
+ log.info("Started");
+ }
+
+ @Deactivate
+ public void deactivate() {
+ eventDispatcher.removeSink(ClusterEvent.class);
+ log.info("Stopped");
+ }
+
+ @Override
+ public ControllerNode getLocalNode() {
+ return store.getLocalNode();
+ }
+
+ @Override
+ public Set<ControllerNode> getNodes() {
+ return store.getNodes();
+ }
+
+ @Override
+ public ControllerNode getNode(NodeId nodeId) {
+ checkNotNull(nodeId, INSTANCE_ID_NULL);
+ return store.getNode(nodeId);
+ }
+
+ @Override
+ public ControllerNode.State getState(NodeId nodeId) {
+ checkNotNull(nodeId, INSTANCE_ID_NULL);
+ return store.getState(nodeId);
+ }
+
+ @Override
+ public void addListener(ClusterEventListener listener) {
+ listenerRegistry.addListener(listener);
+ }
+
+ @Override
+ public void removeListener(ClusterEventListener listener) {
+ listenerRegistry.removeListener(listener);
+ }
+}