ONOS-1479 -- GUI - augmenting topology view for extensibility: WIP.
- Major refactoring of TopologyViewMessageHandler and related classes.

Change-Id: I920f7f9f7317f3987a9a8da35ac086e9f8cab8d3
diff --git a/core/api/src/main/java/org/onosproject/ui/topo/TopoElementType.java b/core/api/src/main/java/org/onosproject/ui/topo/TopoElementType.java
new file mode 100644
index 0000000..dc32746
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/ui/topo/TopoElementType.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright 2015 Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package org.onosproject.ui.topo;
+
+/**
+ * The topology element types to which a highlight can be applied.
+ */
+public enum TopoElementType {
+    DEVICE, HOST, LINK
+}