Implemented new GetTopicByUniqueKey() extension

JeremyCaney · JeremyCaney · commit 867b110fdc7d · 2020-05-02T18:15:09.000-07:00
The new `GetTopicByUniqueKey()` extension takes the functionality previously implemented in the private `GetTopic()` method and makes it broadly available for other aspects of the application. This allows us to greatly simplify the code in `CachedTopicRepository` by replacing `GetTopic()` entirely with a simple call to `GetByUniqueKey()`.

Ironically, this new approach should actually be _faster_, and certainly requires _less code_, even despite having to start from an arbitrary place within the topic graph. This is because of a more economical approach to how the tree is traversed by simply breaking the `uniqueKey` into an array and looping over that array as part of the traversal.
diff --git a/OnTopic.Data.Caching/CachedTopicRepository.cs b/OnTopic.Data.Caching/CachedTopicRepository.cs
@@ -102,7 +102,7 @@ public CachedTopicRepository(ITopicRepository dataProvider) : base() {
       | Lookup by TopicKey
       \-----------------------------------------------------------------------------------------------------------------------*/
       if (topicKey != null && !topicKey.Length.Equals(0)) {
-        return GetTopic(_cache, topicKey);
+        return _cache.GetByUniqueKey(topicKey);
       }
 
       /*------------------------------------------------------------------------------------------------------------------------
@@ -131,76 +131,6 @@ public CachedTopicRepository(ITopicRepository dataProvider) : base() {
 
     }
 
-    /*==========================================================================================================================
-    | METHOD: GET TOPIC
-    \-------------------------------------------------------------------------------------------------------------------------*/
-    /// <summary>
-    ///   Retrieves a topic object based on the specified partial or full (prefixed) topic key.
-    /// </summary>
-    /// <param name="sourceTopic">The root topic to search from.</param>
-    /// <param name="uniqueKey">
-    ///   The partial or full string value representing the key (or <see cref="Topic.GetUniqueKey"/>) for the topic.
-    /// </param>
-    /// <returns>The topic or null, if the topic is not found.</returns>
-    private Topic? GetTopic(Topic? sourceTopic, string uniqueKey) {
-
-      /*------------------------------------------------------------------------------------------------------------------------
-      | Validate input
-      \-----------------------------------------------------------------------------------------------------------------------*/
-      if (sourceTopic == null) return null;
-      if (String.IsNullOrWhiteSpace(uniqueKey)) return null;
-
-      /*------------------------------------------------------------------------------------------------------------------------
-      | Provide shortcut for local calls
-      \-----------------------------------------------------------------------------------------------------------------------*/
-      if (uniqueKey.IndexOf(":", StringComparison.InvariantCulture) < 0 && uniqueKey != "Root") {
-        if (sourceTopic.Children.Contains(uniqueKey)) {
-          return sourceTopic.Children[uniqueKey];
-        }
-        return null;
-      }
-
-      /*------------------------------------------------------------------------------------------------------------------------
-      | Provide implicit root
-      >-------------------------------------------------------------------------------------------------------------------------
-      | ###NOTE JJC080313: While a root topic is required by the data structure, it should be implicit from the perspective of
-      | the calling application.  A developer should be able to call GetTopic("Namespace:TopicPath") to get to a topic, without
-      | needing to be aware of the root.
-      \-----------------------------------------------------------------------------------------------------------------------*/
-      if (
-        !uniqueKey.StartsWith("Root:", StringComparison.OrdinalIgnoreCase) &&
-        !uniqueKey.Equals("Root", StringComparison.OrdinalIgnoreCase)
-        ) {
-        uniqueKey = "Root:" + uniqueKey;
-      }
-
-      /*------------------------------------------------------------------------------------------------------------------------
-      | Validate parameters
-      \-----------------------------------------------------------------------------------------------------------------------*/
-      if (!uniqueKey.StartsWith(sourceTopic.GetUniqueKey(), StringComparison.OrdinalIgnoreCase)) return null;
-      if (uniqueKey.Equals(sourceTopic.GetUniqueKey(), StringComparison.OrdinalIgnoreCase)) return sourceTopic;
-
-      /*------------------------------------------------------------------------------------------------------------------------
-      | Define variables
-      \-----------------------------------------------------------------------------------------------------------------------*/
-      var remainder             = uniqueKey.Substring(sourceTopic.GetUniqueKey().Length + 1);
-      var marker                = remainder.IndexOf(":", StringComparison.Ordinal);
-      var nextChild             = (marker < 0) ? remainder : remainder.Substring(0, marker);
-
-      /*------------------------------------------------------------------------------------------------------------------------
-      | Find topic
-      \-----------------------------------------------------------------------------------------------------------------------*/
-      if (!sourceTopic.Children.Contains(nextChild)) return null;
-
-      if (nextChild == remainder) return sourceTopic.Children[nextChild];
-
-      /*------------------------------------------------------------------------------------------------------------------------
-      | Return the topic
-      \-----------------------------------------------------------------------------------------------------------------------*/
-      return GetTopic(sourceTopic.Children[nextChild], uniqueKey);
-
-    }
-
     /*==========================================================================================================================
     | METHOD: SAVE
     \-------------------------------------------------------------------------------------------------------------------------*/
