ONOS-1478 - GUI -- Segment navigation menu into categories.

Change-Id: I54bddcada1541ebf2926a6536e4c14bb8a1d3a66
diff --git a/core/api/src/main/java/org/onosproject/ui/UiView.java b/core/api/src/main/java/org/onosproject/ui/UiView.java
index 6e3a1a2..e406a6d 100644
--- a/core/api/src/main/java/org/onosproject/ui/UiView.java
+++ b/core/api/src/main/java/org/onosproject/ui/UiView.java
@@ -41,7 +41,14 @@
         /**
          * Represents miscellaneous views.
          */
-        OTHER("Other");
+        OTHER("Other"),
+
+        /**
+         * Represents views that do not show in the navigation menu.
+         * This category should not be specified directly; rather, use
+         * the {@link UiViewHidden} constructor instead of {@link UiView}.
+         */
+        HIDDEN("(hidden)");
 
         private final String label;
 
@@ -64,7 +71,8 @@
     private final Category category;
 
     /**
-     * Creates a new user interface view descriptor.
+     * Creates a new user interface view descriptor. The navigation item
+     * will appear in the navigation menu under the specified category.
      *
      * @param category view category
      * @param id       view identifier
diff --git a/core/api/src/main/java/org/onosproject/ui/UiViewHidden.java b/core/api/src/main/java/org/onosproject/ui/UiViewHidden.java
index 072404e..b7fea8f 100644
--- a/core/api/src/main/java/org/onosproject/ui/UiViewHidden.java
+++ b/core/api/src/main/java/org/onosproject/ui/UiViewHidden.java
@@ -29,7 +29,7 @@
      * @param id view identifier
      */
     public UiViewHidden(String id) {
-        super(Category.OTHER, id, null);
+        super(Category.HIDDEN, id, null);
     }
 
     @Override