Enahnced link and host stores to extend general store.
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleHostStore.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleHostStore.java
index bcd84df..be609a8 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleHostStore.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleHostStore.java
@@ -24,8 +24,10 @@
 import org.onlab.onos.net.host.HostDescription;
 import org.onlab.onos.net.host.HostEvent;
 import org.onlab.onos.net.host.HostStore;
+import org.onlab.onos.net.host.HostStoreDelegate;
 import org.onlab.onos.net.host.PortAddresses;
 import org.onlab.onos.net.provider.ProviderId;
+import org.onlab.onos.store.AbstractStore;
 import org.onlab.packet.IpPrefix;
 import org.onlab.packet.MacAddress;
 import org.onlab.packet.VlanId;
@@ -41,7 +43,9 @@
  */
 @Component(immediate = true)
 @Service
-public class SimpleHostStore implements HostStore {
+public class SimpleHostStore
+        extends AbstractStore<HostEvent, HostStoreDelegate>
+        implements HostStore {
 
     private final Logger log = getLogger(getClass());