Cleaned up some of the host-related abstractions and filled in more of the host manager implementation.
diff --git a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkManager.java b/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkManager.java
index 88d0663..d900c5b 100644
--- a/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkManager.java
+++ b/core/trivial/src/main/java/org/onlab/onos/net/trivial/impl/SimpleLinkManager.java
@@ -66,11 +66,6 @@
     }
 
     @Override
-    protected LinkProviderService createProviderService(LinkProvider provider) {
-        return new InternalLinkProviderService(provider);
-    }
-
-    @Override
     public int getLinkCount() {
         return store.getLinkCount();
     }
@@ -145,6 +140,11 @@
         listenerRegistry.removeListener(listener);
     }
 
+    @Override
+    protected LinkProviderService createProviderService(LinkProvider provider) {
+        return new InternalLinkProviderService(provider);
+    }
+
     // Personalized link provider service issued to the supplied provider.
     private class InternalLinkProviderService extends AbstractProviderService<LinkProvider>
     implements LinkProviderService {