Improve tracking of Ids

src/Microsoft.OData.Core/JsonLight/ODataJsonLightBatchReader.cs

@@ -54,16 +54,9 @@ internal sealed class ODataJsonLightBatchReader : ODataBatchReader
         private ODataJsonLightBatchPayloadItemPropertiesCache messagePropertiesCache = null;
 
         /// <summary>
-        /// Dictionary for keeping track of each request's associated atomic group id, which is null
-        /// for request that does not belong to atomic group.
+        /// Collection for keeping track of unique atomic group ids and member request ids.
         /// </summary>
-        private Dictionary<string, string> requestIdToAtomicGroupId = new Dictionary<string, string>();
-
-        /// <summary>
-        /// Dictionary for keeping track of each atomic group's member request id. This is optimization
-        /// for reversed lookup.
-        /// </summary>
-        private Dictionary<string, IList<string>> atomicityGroupIdToRequestId = new Dictionary<string, IList<string>>();
+        private HashSet<string> requestIds = new HashSet<string>();
 
         /// <summary>
         /// Constructor.
@@ -136,19 +129,14 @@ protected override ODataBatchOperationRequestMessage CreateOperationRequestMessa
             string atomicityGroupId = (string)this.messagePropertiesCache.GetPropertyValue(
                 ODataJsonLightBatchPayloadItemPropertiesCache.PropertyNameAtomicityGroup);
 
-            if (id != null && !this.requestIdToAtomicGroupId.ContainsKey(id))
+            if (id != null)
             {
-                this.requestIdToAtomicGroupId.Add(id, atomicityGroupId);
+                this.requestIds.Add(id);
             }
 
             if (atomicityGroupId != null)
             {
-                if (!this.atomicityGroupIdToRequestId.ContainsKey(atomicityGroupId))
-                {
-                    this.atomicityGroupIdToRequestId.Add(atomicityGroupId, new List<string>() { id });
-                }
-
-                this.atomicityGroupIdToRequestId[atomicityGroupId].Add(id);
+                this.requestIds.Add(atomicityGroupId);
             }
 
             // dependsOn
@@ -370,8 +358,8 @@ protected override void ValidateDependsOnIds(string contentId, IEnumerable<strin
                 // Content-ID cannot be part of dependsOnIds. This is to avoid self referencing.
                 // The dependsOnId must be an existing request ID or atomicityGroup
                 if (id == contentId ||
-                    (!this.requestIdToAtomicGroupId.ContainsKey(id) &&
-                    !this.atomicityGroupIdToRequestId.ContainsKey(id)))
+                    (!this.requestIds.Contains(id) &&
+                    !this.requestIds.Contains(id)))
                 {
                     throw new ODataException(Strings.ODataBatchReader_DependsOnIdNotFound(id, contentId));
                 }