Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / System / Linq / Parallel / QueryOperators / Inlined / NullableDecimalSumAggregationOperator.cs / 1305376 / NullableDecimalSumAggregationOperator.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // NullableDecimalSumAggregationOperator.cs // //[....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Collections.Generic; using System.Diagnostics.Contracts; using System.Threading; namespace System.Linq.Parallel { ////// An inlined sum aggregation and its enumerator, for nullable decimals. /// internal sealed class NullableDecimalSumAggregationOperator : InlinedAggregationOperator{ //---------------------------------------------------------------------------------------- // Constructs a new instance of a sum associative operator. // internal NullableDecimalSumAggregationOperator(IEnumerable child) : base(child) { } //--------------------------------------------------------------------------------------- // Executes the entire query tree, and aggregates the intermediate results into the // final result based on the binary operators and final reduction. // // Return Value: // The single result of aggregation. // protected override decimal? InternalAggregate(ref Exception singularExceptionToThrow) { // Because the final reduction is typically much cheaper than the intermediate // reductions over the individual partitions, and because each parallel partition // will do a lot of work to produce a single output element, we prefer to turn off // pipelining, and process the final reductions serially. using (IEnumerator enumerator = GetEnumerator(ParallelMergeOptions.FullyBuffered, true)) { // We just reduce the elements in each output partition. decimal sum = 0.0m; while (enumerator.MoveNext()) { sum += enumerator.Current.GetValueOrDefault(); } return sum; } } //--------------------------------------------------------------------------------------- // Creates an enumerator that is used internally for the final aggregation step. // protected override QueryOperatorEnumerator CreateEnumerator ( int index, int count, QueryOperatorEnumerator source, object sharedData, CancellationToken cancellationToken) { return new NullableDecimalSumAggregationOperatorEnumerator (source, index, cancellationToken); } //--------------------------------------------------------------------------------------- // This enumerator type encapsulates the intermediary aggregation over the underlying // (possibly partitioned) data source. // private class NullableDecimalSumAggregationOperatorEnumerator : InlinedAggregationOperatorEnumerator { private readonly QueryOperatorEnumerator m_source; // The source data. //---------------------------------------------------------------------------------------- // Instantiates a new aggregation operator. // internal NullableDecimalSumAggregationOperatorEnumerator(QueryOperatorEnumerator source, int partitionIndex, CancellationToken cancellationToken) : base(partitionIndex, cancellationToken) { Contract.Assert(source != null); m_source = source; } //--------------------------------------------------------------------------------------- // Tallies up the sum of the underlying data source, walking the entire thing the first // time MoveNext is called on this object. // protected override bool MoveNextCore(ref decimal? currentElement) { decimal? element = default(decimal?); TKey keyUnused = default(TKey); QueryOperatorEnumerator source = m_source; if (source.MoveNext(ref element, ref keyUnused)) { // We just scroll through the enumerator and accumulate the sum. decimal tempSum = 0.0m; int i = 0; do { if ((i++ & CancellationState.POLL_INTERVAL) == 0) CancellationState.ThrowIfCanceled(m_cancellationToken); tempSum += element.GetValueOrDefault(); } while (source.MoveNext(ref element, ref keyUnused)); // The sum has been calculated. Now just return. currentElement = new decimal?(tempSum); return true; } return false; } //---------------------------------------------------------------------------------------- // Dispose of resources associated with the underlying enumerator. // protected override void Dispose(bool disposing) { Contract.Assert(m_source != null); m_source.Dispose(); } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ // // NullableDecimalSumAggregationOperator.cs // // [....] // // =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- using System.Collections.Generic; using System.Diagnostics.Contracts; using System.Threading; namespace System.Linq.Parallel { ////// An inlined sum aggregation and its enumerator, for nullable decimals. /// internal sealed class NullableDecimalSumAggregationOperator : InlinedAggregationOperator{ //---------------------------------------------------------------------------------------- // Constructs a new instance of a sum associative operator. // internal NullableDecimalSumAggregationOperator(IEnumerable child) : base(child) { } //--------------------------------------------------------------------------------------- // Executes the entire query tree, and aggregates the intermediate results into the // final result based on the binary operators and final reduction. // // Return Value: // The single result of aggregation. // protected override decimal? InternalAggregate(ref Exception singularExceptionToThrow) { // Because the final reduction is typically much cheaper than the intermediate // reductions over the individual partitions, and because each parallel partition // will do a lot of work to produce a single output element, we prefer to turn off // pipelining, and process the final reductions serially. using (IEnumerator enumerator = GetEnumerator(ParallelMergeOptions.FullyBuffered, true)) { // We just reduce the elements in each output partition. decimal sum = 0.0m; while (enumerator.MoveNext()) { sum += enumerator.Current.GetValueOrDefault(); } return sum; } } //--------------------------------------------------------------------------------------- // Creates an enumerator that is used internally for the final aggregation step. // protected override QueryOperatorEnumerator CreateEnumerator ( int index, int count, QueryOperatorEnumerator source, object sharedData, CancellationToken cancellationToken) { return new NullableDecimalSumAggregationOperatorEnumerator (source, index, cancellationToken); } //--------------------------------------------------------------------------------------- // This enumerator type encapsulates the intermediary aggregation over the underlying // (possibly partitioned) data source. // private class NullableDecimalSumAggregationOperatorEnumerator : InlinedAggregationOperatorEnumerator { private readonly QueryOperatorEnumerator m_source; // The source data. //---------------------------------------------------------------------------------------- // Instantiates a new aggregation operator. // internal NullableDecimalSumAggregationOperatorEnumerator(QueryOperatorEnumerator source, int partitionIndex, CancellationToken cancellationToken) : base(partitionIndex, cancellationToken) { Contract.Assert(source != null); m_source = source; } //--------------------------------------------------------------------------------------- // Tallies up the sum of the underlying data source, walking the entire thing the first // time MoveNext is called on this object. // protected override bool MoveNextCore(ref decimal? currentElement) { decimal? element = default(decimal?); TKey keyUnused = default(TKey); QueryOperatorEnumerator source = m_source; if (source.MoveNext(ref element, ref keyUnused)) { // We just scroll through the enumerator and accumulate the sum. decimal tempSum = 0.0m; int i = 0; do { if ((i++ & CancellationState.POLL_INTERVAL) == 0) CancellationState.ThrowIfCanceled(m_cancellationToken); tempSum += element.GetValueOrDefault(); } while (source.MoveNext(ref element, ref keyUnused)); // The sum has been calculated. Now just return. currentElement = new decimal?(tempSum); return true; } return false; } //---------------------------------------------------------------------------------------- // Dispose of resources associated with the underlying enumerator. // protected override void Dispose(bool disposing) { Contract.Assert(m_source != null); m_source.Dispose(); } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- PolyLineSegment.cs
- ComponentDispatcherThread.cs
- ClientOptions.cs
- SafeIUnknown.cs
- HwndSourceParameters.cs
- BinaryCommonClasses.cs
- HttpListenerException.cs
- SuppressIldasmAttribute.cs
- FormViewInsertedEventArgs.cs
- GridProviderWrapper.cs
- SoundPlayerAction.cs
- SourceFileBuildProvider.cs
- WinFormsComponentEditor.cs
- ApplicationId.cs
- QilCloneVisitor.cs
- StrongNameIdentityPermission.cs
- ObjectKeyFrameCollection.cs
- PaintEvent.cs
- WindowPatternIdentifiers.cs
- _AcceptOverlappedAsyncResult.cs
- MediaTimeline.cs
- CopyOfAction.cs
- CompositeScriptReference.cs
- DataBoundControlHelper.cs
- NumericPagerField.cs
- _KerberosClient.cs
- BitmapMetadataBlob.cs
- ActionFrame.cs
- PointKeyFrameCollection.cs
- iisPickupDirectory.cs
- UnmanagedMarshal.cs
- PageThemeParser.cs
- JsonSerializer.cs
- QueryOutputWriter.cs
- Literal.cs
- _UriSyntax.cs
- FixedSOMPageConstructor.cs
- Int32AnimationBase.cs
- Interlocked.cs
- ParallelTimeline.cs
- HtmlTitle.cs
- SizeValueSerializer.cs
- UrlUtility.cs
- ListenerHandler.cs
- UriParserTemplates.cs
- XmlSerializerAssemblyAttribute.cs
- AssemblyHelper.cs
- SchemaCollectionPreprocessor.cs
- ResourceDescriptionAttribute.cs
- CFStream.cs
- ListCollectionView.cs
- OrCondition.cs
- PaperSize.cs
- XslCompiledTransform.cs
- MimeBasePart.cs
- SystemGatewayIPAddressInformation.cs
- ViewGenerator.cs
- KeyMatchBuilder.cs
- XamlSerializerUtil.cs
- ScrollableControlDesigner.cs
- CornerRadiusConverter.cs
- XmlDataLoader.cs
- XhtmlBasicControlAdapter.cs
- ConnectionPointCookie.cs
- XhtmlBasicTextViewAdapter.cs
- SchemaNamespaceManager.cs
- JoinGraph.cs
- SqlCacheDependencyDatabase.cs
- itemelement.cs
- Pair.cs
- MediaContext.cs
- SerializerProvider.cs
- ResourcePermissionBase.cs
- EnumerableRowCollectionExtensions.cs
- ListBox.cs
- StylusDevice.cs
- Emitter.cs
- GridView.cs
- TrustManagerMoreInformation.cs
- DependencyPropertyValueSerializer.cs
- LookupBindingPropertiesAttribute.cs
- PackageProperties.cs
- ChangeBlockUndoRecord.cs
- DelegatingConfigHost.cs
- SafeIUnknown.cs
- StatusBar.cs
- TableCellCollection.cs
- OSEnvironmentHelper.cs
- XslTransform.cs
- ObjectToken.cs
- PasswordTextContainer.cs
- Descriptor.cs
- TemplateControlParser.cs
- XmlILIndex.cs
- WinFormsComponentEditor.cs
- DataGridView.cs
- UnsafeNativeMethodsMilCoreApi.cs
- Floater.cs
- MarginCollapsingState.cs
- ApplicationHost.cs