Aggregates.cs source code in C# .NET

                        Code:
                         / Dotnetfx_Vista_SP2 / Dotnetfx_Vista_SP2 / 8.0.50727.4016 / DEVDIV / depot / DevDiv / releases / Orcas / QFE / ndp / fx / src / DataEntity / System / Data / Common / CommandTrees / Aggregates.cs / 2 / Aggregates.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner  [....], [....]
//--------------------------------------------------------------------- 
 
using System;
using System.Data.Common; 
using System.Collections.Generic;
using System.Data.Metadata.Edm;
using System.Data.Common.CommandTrees.Internal;
using System.Diagnostics; 

namespace System.Data.Common.CommandTrees 
{ 
    /// 
    /// Aggregates are pseudo-expressions. They look and feel like expressions, but 
    /// are severely restricted in where they can appear - only in the aggregates clause
    /// of a group-by expression.
    /// 
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "Db")] 
    public abstract class DbAggregate
    { 
        private DbCommandTree _commandTree; 
        private ExpressionList _args;
        private TypeUsage _type; 

        internal DbAggregate(DbCommandTree commandTree)
        {
            _commandTree = EntityUtil.CheckArgumentNull(commandTree, "commandTree"); 
        }
 
        internal ExpressionList ArgumentList { get { return _args; } set { _args = value; } } 

        ///  
        /// The DbCommandTree with which this DbAggregate is associated
        /// 
        internal DbCommandTree CommandTree { get { return _commandTree; } }
 
        /// 
        /// Gets the result type of this aggregate 
        ///  
        public TypeUsage ResultType
        { 
            get { return _type; }
            internal set
            {
               // this is causing null ref 
                //Debug.Assert(_type.IsReadOnlyItem, "Editable type specified as DbAggregate.ResultType");
                _type = value; 
            } 
        }
 
        /// 
        /// Gets the list of expressions that define the arguments to the aggregate.
        /// 
        public IList Arguments { get { return _args; } } 
    }
 
#if ENABLE_NESTAGGREGATE 
    /// 
    /// The aggregate type that corresponds to a nesting operation. 
    /// 
    public sealed class NestAggregate : Aggregate
    {
        internal NestAggregate(CommandTree commandTree, Expression arg) 
            : base(commandTree)
        { 
            if (null == arg) 
            {
                throw EntityUtil.ArgumentNull("arg"); 
            }

            this.ArgumentList = new ExpressionList("Arguments", commandTree, arg.ResultType, CommandTreeUtils.CreateList(arg));
            this.ResultType = commandTree.TypeHelper.CreateCollectionType(arg.Type); 
        }
    } 
#endif 

    ///  
    /// The aggregate type that corresponds to the invocation of an aggregate function.
    /// 
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "Db")]
    public sealed class DbFunctionAggregate : DbAggregate 
    {
        private bool _distinct; 
        EdmFunction _aggregateFunction; 

        internal DbFunctionAggregate(DbCommandTree commandTree, EdmFunction function, DbExpression arg, bool isDistinct) 
            : base(commandTree)
        {
            EntityUtil.CheckArgumentNull(arg, "arg");
 
            _distinct = isDistinct;
 
            // 
            // Verify that the aggregate function is from the metadata collection and data space of the command tree.
            // 
            commandTree.TypeHelper.CheckFunction(function);

            // Verify that the function is actually a valid aggregate function.
            // For now, only a single argument is allowed. 
            if (!TypeSemantics.IsAggregateFunction(function) ||
                null == function.ReturnParameter || 
                TypeSemantics.IsNullOrNullType(function.ReturnParameter.TypeUsage)) 
            {
                throw EntityUtil.Argument(System.Data.Entity.Strings.Cqt_Aggregate_InvalidFunction, "function"); 
            }

            _aggregateFunction = function;
 
            // Create an ExpressionList without initializing the expected element types or element values
            this.ArgumentList = new ExpressionList("Arguments", commandTree, function.Parameters.Count); 
            List funcArgs = CommandTreeUtils.CreateList(arg); 

            // 
            // Set the expected element type for each element in the ExpressionList based on the parameter
            // type of each formal parameter to the function. For each parameter, if its parameter type is
            // a collection type then the element type of that collection will be used. Otherwise the parameter
            // type itself will be used. This is necessary because aggregate functions may be used outside of 
            // GroupBy and therefore always specify their parameter types as collection types. From within
            // GroupBy the (non-collection) GroupVar may legally be passed to the same aggregate function. 
            // After the expected element type is set, the element value is set. This causes ExpressionLink type 
            // checking and other expression validation to occur against the expected element type that was just set.
            // 
            Debug.Assert(funcArgs.Count == function.Parameters.Count, "Incorrect number of arguments specified for DbFunctionAggregate");
            for (int idx = 0; idx < funcArgs.Count; idx++)
            {
                TypeUsage paramType = function.Parameters[idx].TypeUsage; 
                TypeUsage elementType = null;
                if(TypeHelpers.TryGetCollectionElementType(paramType, out elementType)) 
                { 
                    paramType = elementType;
                } 

                this.ArgumentList.ExpressionLinks[idx].SetExpectedType(paramType);
                this.ArgumentList.ExpressionLinks[idx].InitializeValue(funcArgs[idx]);
            } 

            this.ResultType = function.ReturnParameter.TypeUsage; 
        } 

        ///  
        /// Gets a value indicating whether the aggregate function is applied in a distinct fashion
        /// 
        public bool Distinct { get { return _distinct; } }
 
        /// 
        /// Gets the method metadata that specifies the aggregate function to invoke. 
        ///  
        public EdmFunction Function { get { return _aggregateFunction; } }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner  [....], [....]
//--------------------------------------------------------------------- 
 
using System;
using System.Data.Common; 
using System.Collections.Generic;
using System.Data.Metadata.Edm;
using System.Data.Common.CommandTrees.Internal;
using System.Diagnostics; 

namespace System.Data.Common.CommandTrees 
{ 
    /// 
    /// Aggregates are pseudo-expressions. They look and feel like expressions, but 
    /// are severely restricted in where they can appear - only in the aggregates clause
    /// of a group-by expression.
    /// 
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "Db")] 
    public abstract class DbAggregate
    { 
        private DbCommandTree _commandTree; 
        private ExpressionList _args;
        private TypeUsage _type; 

        internal DbAggregate(DbCommandTree commandTree)
        {
            _commandTree = EntityUtil.CheckArgumentNull(commandTree, "commandTree"); 
        }
 
        internal ExpressionList ArgumentList { get { return _args; } set { _args = value; } } 

        ///  
        /// The DbCommandTree with which this DbAggregate is associated
        /// 
        internal DbCommandTree CommandTree { get { return _commandTree; } }
 
        /// 
        /// Gets the result type of this aggregate 
        ///  
        public TypeUsage ResultType
        { 
            get { return _type; }
            internal set
            {
               // this is causing null ref 
                //Debug.Assert(_type.IsReadOnlyItem, "Editable type specified as DbAggregate.ResultType");
                _type = value; 
            } 
        }
 
        /// 
        /// Gets the list of expressions that define the arguments to the aggregate.
        /// 
        public IList Arguments { get { return _args; } } 
    }
 
#if ENABLE_NESTAGGREGATE 
    /// 
    /// The aggregate type that corresponds to a nesting operation. 
    /// 
    public sealed class NestAggregate : Aggregate
    {
        internal NestAggregate(CommandTree commandTree, Expression arg) 
            : base(commandTree)
        { 
            if (null == arg) 
            {
                throw EntityUtil.ArgumentNull("arg"); 
            }

            this.ArgumentList = new ExpressionList("Arguments", commandTree, arg.ResultType, CommandTreeUtils.CreateList(arg));
            this.ResultType = commandTree.TypeHelper.CreateCollectionType(arg.Type); 
        }
    } 
#endif 

    ///  
    /// The aggregate type that corresponds to the invocation of an aggregate function.
    /// 
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "Db")]
    public sealed class DbFunctionAggregate : DbAggregate 
    {
        private bool _distinct; 
        EdmFunction _aggregateFunction; 

        internal DbFunctionAggregate(DbCommandTree commandTree, EdmFunction function, DbExpression arg, bool isDistinct) 
            : base(commandTree)
        {
            EntityUtil.CheckArgumentNull(arg, "arg");
 
            _distinct = isDistinct;
 
            // 
            // Verify that the aggregate function is from the metadata collection and data space of the command tree.
            // 
            commandTree.TypeHelper.CheckFunction(function);

            // Verify that the function is actually a valid aggregate function.
            // For now, only a single argument is allowed. 
            if (!TypeSemantics.IsAggregateFunction(function) ||
                null == function.ReturnParameter || 
                TypeSemantics.IsNullOrNullType(function.ReturnParameter.TypeUsage)) 
            {
                throw EntityUtil.Argument(System.Data.Entity.Strings.Cqt_Aggregate_InvalidFunction, "function"); 
            }

            _aggregateFunction = function;
 
            // Create an ExpressionList without initializing the expected element types or element values
            this.ArgumentList = new ExpressionList("Arguments", commandTree, function.Parameters.Count); 
            List funcArgs = CommandTreeUtils.CreateList(arg); 

            // 
            // Set the expected element type for each element in the ExpressionList based on the parameter
            // type of each formal parameter to the function. For each parameter, if its parameter type is
            // a collection type then the element type of that collection will be used. Otherwise the parameter
            // type itself will be used. This is necessary because aggregate functions may be used outside of 
            // GroupBy and therefore always specify their parameter types as collection types. From within
            // GroupBy the (non-collection) GroupVar may legally be passed to the same aggregate function. 
            // After the expected element type is set, the element value is set. This causes ExpressionLink type 
            // checking and other expression validation to occur against the expected element type that was just set.
            // 
            Debug.Assert(funcArgs.Count == function.Parameters.Count, "Incorrect number of arguments specified for DbFunctionAggregate");
            for (int idx = 0; idx < funcArgs.Count; idx++)
            {
                TypeUsage paramType = function.Parameters[idx].TypeUsage; 
                TypeUsage elementType = null;
                if(TypeHelpers.TryGetCollectionElementType(paramType, out elementType)) 
                { 
                    paramType = elementType;
                } 

                this.ArgumentList.ExpressionLinks[idx].SetExpectedType(paramType);
                this.ArgumentList.ExpressionLinks[idx].InitializeValue(funcArgs[idx]);
            } 

            this.ResultType = function.ReturnParameter.TypeUsage; 
        } 

        ///  
        /// Gets a value indicating whether the aggregate function is applied in a distinct fashion
        /// 
        public bool Distinct { get { return _distinct; } }
 
        /// 
        /// Gets the method metadata that specifies the aggregate function to invoke. 
        ///  
        public EdmFunction Function { get { return _aggregateFunction; } }
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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