Added application that adds a topology overlay displaying additional statistics of links.

Change-Id: Ie82ce67ead64b9b62d6ab55f3ef8ac0f62946d9f
diff --git a/apps/linkprops/src/main/resources/app/view/lpTopov/lpTopov.js b/apps/linkprops/src/main/resources/app/view/lpTopov/lpTopov.js
new file mode 100644
index 0000000..5596a82
--- /dev/null
+++ b/apps/linkprops/src/main/resources/app/view/lpTopov/lpTopov.js
@@ -0,0 +1,103 @@
+/*
+ * Copyright 2015-present 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.
+ */
+
+/*
+ Module containing the "business logic" for the Link Props topology overlay.
+ */
+
+(function () {
+    'use strict';
+
+    // injected refs
+    var $log, fs, flash, wss;
+
+    // constants
+    var displayStart = 'linkPropsTopovDisplayStart',
+        displayUpdate = 'linkPropsTopovDisplayUpdate',
+        displayStop = 'linkPropsTopovDisplayStop';
+
+    // internal state
+    var currentMode = null;
+
+
+    // === ---------------------------
+    // === Helper functions
+
+    function sendDisplayStart(mode) {
+        wss.sendEvent(displayStart, {
+            mode: mode
+        });
+    }
+
+    function sendDisplayUpdate(what) {
+        wss.sendEvent(displayUpdate, {
+            id: what ? what.id : ''
+        });
+    }
+
+    function sendDisplayStop() {
+        wss.sendEvent(displayStop);
+    }
+
+    // === ---------------------------
+    // === Main API functions
+
+    function startDisplay(mode) {
+        if (currentMode === mode) {
+            $log.debug('(in mode', mode, 'already)');
+        } else {
+            currentMode = mode;
+            sendDisplayStart(mode);
+            flash.flash('Starting display mode: ' + mode);
+        }
+    }
+
+    function updateDisplay(m) {
+        if (currentMode) {
+            sendDisplayUpdate(m);
+        }
+    }
+
+    function stopDisplay() {
+        if (currentMode) {
+            currentMode = null;
+            sendDisplayStop();
+            flash.flash('Canceling display mode');
+            return true;
+        }
+        return false;
+    }
+
+    // === ---------------------------
+    // === Module Factory Definition
+
+    angular.module('ovLpTopov', [])
+        .factory('LinkPropsTopovService',
+        ['$log', 'FnService', 'FlashService', 'WebSocketService',
+
+        function (_$log_, _fs_, _flash_, _wss_) {
+            $log = _$log_;
+            fs = _fs_;
+            flash = _flash_;
+            wss = _wss_;
+
+            return {
+                startDisplay: startDisplay,
+                updateDisplay: updateDisplay,
+                stopDisplay: stopDisplay
+            };
+        }]);
+}());