ONOS-314 Added ability to export JSON via GUI rest.

Change-Id: I8cc6011f54ce6a3fb50916a74cabb7234b04ef39

-/*
- * Copyright 2014 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.onlab.onos.gui;
-
-import org.onlab.rest.BaseResource;
-
-import javax.ws.rs.DefaultValue;
-import javax.ws.rs.GET;
-import javax.ws.rs.Path;
-import javax.ws.rs.QueryParam;
-import javax.ws.rs.core.Response;
-
-/**
- * Simple example of a GUI JAX-RS resource.
- */
-@Path("greet")
-public class GreetResource extends BaseResource {
-
-    @GET
-    public Response yo(@QueryParam("name") @DefaultValue("dude") String name) {
-        return Response.ok("Yo!!!").build();
-    }
-
-}

@@ -66,6 +66,7 @@ import org.slf4j.LoggerFactory;
 
 import java.text.DecimalFormat;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -129,6 +130,15 @@ public abstract class TopologyViewMessages {
     private static Map<String, ObjectNode> metaUi = new ConcurrentHashMap<>();
 
     /**
+     * Returns read-only view of the meta-ui information.
+     *
+     * @return map of id to meta-ui mementos
+     */
+    static Map<String, ObjectNode> getMetaUi() {
+        return Collections.unmodifiableMap(metaUi);
+    }
+
+    /**
      * Creates a messaging facility for creating messages for topology viewer.
      *
      * @param directory service directory