Introduced TryAdd()

JeremyCaney · JeremyCaney · commit 027ae25b7242 · 2020-09-01T11:22:22.000-07:00
When adding a type, it is conceivable that a class being derived from has already added that type. For this reason, most derivatives of `StaticTypeLookupService` implement local checks to avoid a key conflict. Since this is such a common scenario, that logic is being centralized as a `TryAdd()` method. This method will add the `Type` if no `Type` with the same key exists. Otherwise, it will simply return `false`, instead of throwing an exception. If an exception is preferred in this scenario, the existing `Add()` method will satisfy that condition. This complements the newly added `AddOrReplace()` method, which will replace the existing `Type` if it exists (cd92791).
diff --git a/OnTopic/StaticTypeLookupService.cs b/OnTopic/StaticTypeLookupService.cs
@@ -95,6 +95,22 @@ public StaticTypeLookupService(
     /// </summary>
     protected void Add(Type type) => _typeCollection.Add(type);
 
+    /*==========================================================================================================================
+    | METHOD: TRY ADD
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Determines if a <see cref="Type"/> with the given <see cref="MemberInfo.Name"/> exists. If it does, returns <c>false
+    ///   </c>; otherwise, adds the <see cref="Type"/> and returns <c>true</c>.
+    /// </summary>
+    protected bool TryAdd(Type type) {
+      Contract.Requires(type, nameof(type));
+      if (Contains(type.Name)) {
+        return false;
+      }
+      Add(type);
+      return true;
+    }
+
     /*==========================================================================================================================
     | METHOD: ADD OR REPLACE
     \-------------------------------------------------------------------------------------------------------------------------*/
