[Telemetry] Add subscriber service

Add a subscriber service to handle subscribing to
whole sets of telemetry elements via delegation;
this exposes TelemetrySubscription via a service
which can be retrieved via dependency injection.
Supports the use of this variety of subscription
for autoflow tabular views, WTD-614.

platform/telemetry/bundle.json

@@ -28,6 +28,11 @@
             {
                 "key": "telemetryFormatter",
                 "implementation": "TelemetryFormatter.js"
+            },
+            {
+                "key": "telemetrySubscriber",
+                "implementation": "TelemetrySubscriber.js",
+                "depends": [ "$q", "$timeout" ]
             }
         ]
     }

platform/telemetry/src/TelemetrySubscriber.js

@@ -1,107 +1,23 @@
 /*global define*/
 
 define(
-    [],
+    ["./TelemetrySubscription"],
-    function () {
+    function (TelemetrySubscription) {
         "use strict";
 
-        function TelemetrySubscriber($q, $timeout, domainObject, callback) {
+        function TelemetrySubscriber($q, $timeout) {
-            var unsubscribePromise,
-                latestValues = {},
-                telemetryObjects = [],
-                updatePending;
-
-            // Look up domain objects which have telemetry capabilities.
-            // This will either be the object in view, or object that
-            // this object delegates its telemetry capability to.
-            function promiseRelevantObjects(domainObject) {
-                // If object has been cleared, there are no relevant
-                // telemetry-providing domain objects.
-                if (!domainObject) {
-                    return $q.when([]);
-                }
-
-                // Otherwise, try delegation first, and attach the
-                // object itself if it has a telemetry capability.
-                return $q.when(domainObject.useCapability(
-                    "delegation",
-                    "telemetry"
-                )).then(function (result) {
-                    var head = domainObject.hasCapability("telemetry") ?
-                            [ domainObject ] : [],
-                        tail = result || [];
-                    return head.concat(tail);
-                });
-            }
-
-            function fireCallback(values) {
-                callback(values);
-                updatePending = false;
-            }
-
-            function update(domainObject, telemetry) {
-                var count = telemetry && telemetry.getPointCount();
-
-                if (!updatePending && count) {
-                    updatePending = true;
-                    $timeout(fireCallback, 0);
-                }
-
-                if (count > 0) {
-                    latestValues[domainObject.getId()] = {
-                        domain: telemetry.getDomainValue(count - 1),
-                        range: telemetry.getRangeValue(count - 1)
-                    };
-                }
-            }
-
-            function subscribe(domainObject) {
-                var telemetryCapability =
-                    domainObject.getCapability("telemetry");
-                return telemetryCapability.subscribe(function (telemetry) {
-                    update(domainObject, telemetry);
-                });
-            }
-
-            function subscribeAll(domainObjects) {
-                return domainObjects.map(subscribe);
-            }
-
-            function cacheObjectReferences(objects) {
-                telemetryObjects = objects;
-                return objects;
-            }
-
-            // Get a reference to relevant objects (those with telemetry
-            // capabilities)
-            unsubscribePromise =
-                promiseRelevantObjects(domainObject)
-                    .then(cacheObjectReferences)
-                    .then(subscribeAll);
-
             return {
-                unsubscribe: function () {
+                subscribe: function (domainObject, callback) {
-                    return unsubscribePromise.then(function (unsubscribes) {
+                    return new TelemetrySubscription(
-                        return $q.all(unsubscribes.map(function (unsubscribe) {
+                        $q,
-                            return unsubscribe();
+                        $timeout,
-                        }));
+                        domainObject,
-                    });
+                        callback
-                },
+                    );
-                getDomainValue: function (domainObject) {
-                    var id = domainObject.getId();
-                    return (latestValues[id] || {}).domain;
-                },
-                getRangeValue: function (domainObject) {
-                    var id = domainObject.getId();
-                    return (latestValues[id] || {}).range;
-                },
-                getTelemetryObjects: function () {
-                    return telemetryObjects;
                 }
             };
         }
 
         return TelemetrySubscriber;
-
     }
 );

platform/telemetry/src/TelemetrySubscription.js

@@ -0,0 +1,107 @@
+/*global define*/
+
+define(
+    [],
+    function () {
+        "use strict";
+
+        function TelemetrySubscription($q, $timeout, domainObject, callback) {
+            var unsubscribePromise,
+                latestValues = {},
+                telemetryObjects = [],
+                updatePending;
+
+            // Look up domain objects which have telemetry capabilities.
+            // This will either be the object in view, or object that
+            // this object delegates its telemetry capability to.
+            function promiseRelevantObjects(domainObject) {
+                // If object has been cleared, there are no relevant
+                // telemetry-providing domain objects.
+                if (!domainObject) {
+                    return $q.when([]);
+                }
+
+                // Otherwise, try delegation first, and attach the
+                // object itself if it has a telemetry capability.
+                return $q.when(domainObject.useCapability(
+                    "delegation",
+                    "telemetry"
+                )).then(function (result) {
+                    var head = domainObject.hasCapability("telemetry") ?
+                            [ domainObject ] : [],
+                        tail = result || [];
+                    return head.concat(tail);
+                });
+            }
+
+            function fireCallback(values) {
+                callback(values);
+                updatePending = false;
+            }
+
+            function update(domainObject, telemetry) {
+                var count = telemetry && telemetry.getPointCount();
+
+                if (!updatePending && count) {
+                    updatePending = true;
+                    $timeout(fireCallback, 0);
+                }
+
+                if (count > 0) {
+                    latestValues[domainObject.getId()] = {
+                        domain: telemetry.getDomainValue(count - 1),
+                        range: telemetry.getRangeValue(count - 1)
+                    };
+                }
+            }
+
+            function subscribe(domainObject) {
+                var telemetryCapability =
+                    domainObject.getCapability("telemetry");
+                return telemetryCapability.subscribe(function (telemetry) {
+                    update(domainObject, telemetry);
+                });
+            }
+
+            function subscribeAll(domainObjects) {
+                return domainObjects.map(subscribe);
+            }
+
+            function cacheObjectReferences(objects) {
+                telemetryObjects = objects;
+                return objects;
+            }
+
+            // Get a reference to relevant objects (those with telemetry
+            // capabilities)
+            unsubscribePromise =
+                promiseRelevantObjects(domainObject)
+                    .then(cacheObjectReferences)
+                    .then(subscribeAll);
+
+            return {
+                unsubscribe: function () {
+                    return unsubscribePromise.then(function (unsubscribes) {
+                        return $q.all(unsubscribes.map(function (unsubscribe) {
+                            return unsubscribe();
+                        }));
+                    });
+                },
+                getDomainValue: function (domainObject) {
+                    var id = domainObject.getId();
+                    return (latestValues[id] || {}).domain;
+                },
+                getRangeValue: function (domainObject) {
+                    var id = domainObject.getId();
+                    return (latestValues[id] || {}).range;
+                },
+                getTelemetryObjects: function () {
+                    return telemetryObjects;
+                }
+            };
+        }
+
+        return TelemetrySubscription;
+
+    }
+);