AggregateExpressionDefinition.cs

/* Copyright 2016-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.
*/

usingSystem;
usingSystem.Collections.Generic;
usingSystem.Linq.Expressions;
usingMongoDB.Bson;
usingMongoDB.Bson.Serialization;
usingMongoDB.Driver.Core.Misc;
usingMongoDB.Driver.Linq;
usingMongoDB.Driver.Linq.Linq3Implementation.Misc;
usingMongoDB.Driver.Linq.Linq3Implementation.Translators;

namespaceMongoDB.Driver
{
/// <summary>
/// An aggregation expression.
/// </summary>
/// <typeparam name="TSource">The type of the source.</typeparam>
/// <typeparam name="TResult">The type of the result.</typeparam>
publicabstractclassAggregateExpressionDefinition<TSource,TResult>
{
 #region static
// public implicit conversions
/// <summary>
/// Performs an implicit conversion from <see cref="BsonValue"/> to <see cref="AggregateExpressionDefinition{TSource, TResult}"/>.
/// </summary>
/// <param name="expression">The expression.</param>
/// <returns>
/// The result of the conversion.
/// </returns>
publicstaticimplicitoperatorAggregateExpressionDefinition<TSource,TResult>(BsonValueexpression)
{
Ensure.IsNotNull(expression,nameof(expression));
returnnewBsonValueAggregateExpressionDefinition<TSource,TResult>(expression);
}

/// <summary>
/// Performs an implicit conversion from <see cref="System.String"/> to <see cref="AggregateExpressionDefinition{TSource, TResult}"/>.
/// </summary>
/// <param name="expression">The expression.</param>
/// <returns>
/// The result of the conversion.
/// </returns>
publicstaticimplicitoperatorAggregateExpressionDefinition<TSource,TResult>(stringexpression)
{
Ensure.IsNotNullOrEmpty(expression,nameof(expression));
if(expression[0]=='{')
{
returnnewBsonValueAggregateExpressionDefinition<TSource,TResult>(BsonDocument.Parse(expression));
}
else
{
returnnewBsonValueAggregateExpressionDefinition<TSource,TResult>(newBsonString(expression));
}
}
 #endregion

/// <summary>
/// Renders the aggregation expression to a <see cref="BsonValue"/>.
/// </summary>
/// <param name="args">The render arguments.</param>
/// <returns>A <see cref="BsonValue"/>.</returns>
publicabstractBsonValueRender(RenderArgs<TSource>args);
}

/// <summary>
/// A <see cref="BsonValue"/> based aggregate expression.
/// </summary>
/// <typeparam name="TSource">The type of the source.</typeparam>
/// <typeparam name="TResult">The type of the result.</typeparam>
/// <seealso cref="MongoDB.Driver.AggregateExpressionDefinition{TSource, TResult}" />
publicsealedclassBsonValueAggregateExpressionDefinition<TSource,TResult>:AggregateExpressionDefinition<TSource,TResult>
{
// private fields
privatereadonlyBsonValue_expression;

// constructors
/// <summary>
/// Initializes a new instance of the <see cref="BsonValueAggregateExpressionDefinition{TSource, TResult}"/> class.
/// </summary>
/// <param name="expression">The expression.</param>
publicBsonValueAggregateExpressionDefinition(BsonValueexpression)
{
_expression=Ensure.IsNotNull(expression,nameof(expression));
}

// public methods
/// <inheritdoc/>
publicoverrideBsonValueRender(RenderArgs<TSource>args)
{
return_expression;
}
}

/// <summary>
/// A <see cref="BsonValue"/> based aggregate expression.
/// </summary>
/// <typeparam name="TSource">The type of the source.</typeparam>
/// <typeparam name="TResult">The type of the result.</typeparam>
/// <seealso cref="MongoDB.Driver.AggregateExpressionDefinition{TSource, TResult}" />
publicsealedclassExpressionAggregateExpressionDefinition<TSource,TResult>:AggregateExpressionDefinition<TSource,TResult>
{
// private fields
privatereadonlyTranslationContextData_contextData;
privatereadonlyExpression<Func<TSource,TResult>>_expression;

// constructors
/// <summary>
/// Initializes a new instance of the <see cref="ExpressionAggregateExpressionDefinition{TSource, TResult}" /> class.
/// </summary>
/// <param name="expression">The expression.</param>
publicExpressionAggregateExpressionDefinition(Expression<Func<TSource,TResult>>expression)
:this(expression,null)
{
}

internalExpressionAggregateExpressionDefinition(
Expression<Func<TSource,TResult>>expression,
TranslationContextDatacontextData)
{
_expression=Ensure.IsNotNull(expression,nameof(expression));
_contextData=contextData;// can be null
}

// public methods
/// <inheritdoc/>
publicoverrideBsonValueRender(RenderArgs<TSource>args)
{
varcontextData=_contextData?.With("SerializerRegistry",args.SerializerRegistry);
returnLinqProviderAdapter.TranslateExpressionToAggregateExpression(_expression,args.DocumentSerializer,args.SerializerRegistry,args.TranslationOptions,contextData);
}
}

/// <summary>
/// An aggregate expression for the $documents stage.
/// </summary>
/// <typeparam name="TDocument">The type of the documents.</typeparam>
/// <seealso cref="MongoDB.Driver.AggregateExpressionDefinition{TSource, TResult}" />
publicsealedclassDocumentsAggregateExpressionDefinition<TDocument>:AggregateExpressionDefinition<NoPipelineInput,IEnumerable<TDocument>>
{
// private fields
privatereadonlyIReadOnlyList<TDocument>_documents;
privatereadonlyIBsonSerializer<TDocument>_documentSerializer;

// constructors
/// <summary>
/// Initializes a new instance of the <see cref="ExpressionAggregateExpressionDefinition{TSource, TResult}" /> class.
/// </summary>
/// <param name="documents">The documents.</param>
/// <param name="documentSerializer">The document serializer.</param>
publicDocumentsAggregateExpressionDefinition(
IEnumerable<TDocument>documents,
IBsonSerializer<TDocument>documentSerializer=null)
{
_documents=Ensure.IsNotNull(documents,nameof(documents)).AsReadOnlyList();
_documentSerializer=documentSerializer;// can be null
}

// public methods
/// <inheritdoc/>
publicoverrideBsonValueRender(RenderArgs<NoPipelineInput>args)
{
vardocumentSerializer=_documentSerializer??args.SerializerRegistry.GetSerializer<TDocument>();
returnSerializationHelper.SerializeValues(documentSerializer,_documents);
}
}
}