use separate classes for median and percentile accumulator ASTs

Author: adelinowona

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/AstNodeType.cs

@@ -31,7 +31,6 @@ internal enum AstNodeType
         BucketStage,
         CollStatsStage,
         ComparisonFilterOperation,
-        ComplexAccumulatorExpression,
         ComputedArrayExpression,
         ComputedDocumentExpression,
         ComputedField,
@@ -95,6 +94,7 @@ internal enum AstNodeType
         MatchesNothingFilter,
         MatchStage,
         MedianExpression,
+        MedianAccumulatorExpression,
         MedianWindowExpression,
         MergeStage,
         ModFilterOperation,
@@ -108,6 +108,7 @@ internal enum AstNodeType
         OrFilter,
         OutStage,
         PercentileExpression,
+        PercentileAccumulatorExpression,
         PercentileWindowExpression,
         PickAccumulatorExpression,
         PickExpression,

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/Expressions/AstComplexAccumulatorExpression.cs

@@ -209,11 +209,6 @@ public static AstExpression Comparison(AstBinaryOperator comparisonOperator, Ast
             };
         }
 
-        public static AstComplexAccumulatorExpression ComplexAccumulator(AstComplexAccumulatorOperator @operator, Dictionary<string, AstExpression> args)
-        {
-            return new AstComplexAccumulatorExpression(@operator, args);
-        }
-
         public static AstExpression ComputedArray(IEnumerable<AstExpression> items)
         {
             return new AstComputedArrayExpression(items);
@@ -607,6 +602,11 @@ public static AstExpression Median(AstExpression input)
             return new AstMedianExpression(input);
         }
 
+        public static AstMedianAccumulatorExpression MedianAccumulator(AstExpression input)
+        {
+            return new AstMedianAccumulatorExpression(input);
+        }
+
         public static AstMedianWindowExpression MedianWindowExpression(AstExpression input, AstWindow window)
         {
             return new AstMedianWindowExpression(input, window);
@@ -673,6 +673,11 @@ public static AstPercentileExpression Percentile(AstExpression input, AstExpress
             return new AstPercentileExpression(input, percentiles);
         }
 
+        public static AstPercentileAccumulatorExpression PercentileAccumulator(AstExpression input, AstExpression percentiles)
+        {
+            return new AstPercentileAccumulatorExpression(input, percentiles);
+        }
+
         public static AstPercentileWindowExpression PercentileWindowExpression(AstExpression input, AstExpression percentiles, AstWindow window)
         {
             return new AstPercentileWindowExpression(input, percentiles, window);

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/Expressions/AstComplexAccumulatorOperator.cs

@@ -0,0 +1,64 @@
+/* Copyright 2010-present MongoDB Inc.
+ *
+ * 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.
+ */
+
+using MongoDB.Bson;
+using MongoDB.Driver.Core.Misc;
+using MongoDB.Driver.Linq.Linq3Implementation.Ast.Visitors;
+
+namespace MongoDB.Driver.Linq.Linq3Implementation.Ast.Expressions
+{
+    internal sealed class AstMedianAccumulatorExpression : AstAccumulatorExpression
+    {
+        private readonly AstExpression _input;
+
+        public AstMedianAccumulatorExpression(AstExpression input)
+        {
+            _input = Ensure.IsNotNull(input, nameof(input));
+        }
+
+        public AstExpression Input => _input;
+
+        public override AstNodeType NodeType => AstNodeType.MedianAccumulatorExpression;
+
+        public override AstNode Accept(AstNodeVisitor visitor)
+        {
+            return visitor.VisitMedianAccumulatorExpression(this);
+        }
+
+        public override BsonValue Render()
+        {
+            return new BsonDocument
+            {
+                {
+                    "$median", new BsonDocument
+                    {
+                        { "input", _input.Render() },
+                        { "method", "approximate" } // server requires this parameter but currently only allows this value
+                    }
+                }
+            };
+        }
+
+        public AstMedianAccumulatorExpression Update(AstExpression input)
+        {
+            if (input == _input)
+            {
+                return this;
+            }
+            return new AstMedianAccumulatorExpression(input);
+        }
+
+    }
+}

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/Expressions/AstExpression.cs

@@ -0,0 +1,68 @@
+/* Copyright 2010-present MongoDB Inc.
+ *
+ * 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.
+ */
+
+using MongoDB.Bson;
+using MongoDB.Driver.Core.Misc;
+using MongoDB.Driver.Linq.Linq3Implementation.Ast.Visitors;
+
+namespace MongoDB.Driver.Linq.Linq3Implementation.Ast.Expressions
+{
+    internal sealed class AstPercentileAccumulatorExpression : AstAccumulatorExpression
+    {
+        private readonly AstExpression _input;
+        private readonly AstExpression _percentiles;
+
+        public AstPercentileAccumulatorExpression(AstExpression input, AstExpression percentiles)
+        {
+            _input = Ensure.IsNotNull(input, nameof(input));
+            _percentiles = Ensure.IsNotNull(percentiles, nameof(percentiles));
+        }
+
+        public AstExpression Input => _input;
+
+        public AstExpression Percentiles => _percentiles;
+
+        public override AstNodeType NodeType => AstNodeType.PercentileAccumulatorExpression;
+
+        public override AstNode Accept(AstNodeVisitor visitor)
+        {
+            return visitor.VisitPercentileAccumulatorExpression(this);
+        }
+
+        public override BsonValue Render()
+        {
+            return new BsonDocument
+            {
+                {
+                    "$percentile", new BsonDocument
+                    {
+                        { "input", _input.Render() },
+                        { "p", _percentiles.Render() },
+                        { "method", "approximate" } // server requires this parameter but currently only allows this value
+                    }
+                }
+            };
+        }
+
+        public AstPercentileAccumulatorExpression Update(AstExpression input, AstExpression percentiles)
+        {
+            if (input == _input && percentiles == _percentiles)
+            {
+                return this;
+            }
+            return new AstPercentileAccumulatorExpression(input, percentiles);
+        }
+    }
+}