Code:
/ 4.0 / 4.0 / untmp / 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.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- Bold.cs
- EntityDataSourceViewSchema.cs
- XLinq.cs
- RNGCryptoServiceProvider.cs
- CompiledIdentityConstraint.cs
- MultiDataTrigger.cs
- XmlComplianceUtil.cs
- ExpressionBinding.cs
- _NTAuthentication.cs
- ErrorTableItemStyle.cs
- SafeProcessHandle.cs
- Registry.cs
- SymbolType.cs
- FactoryRecord.cs
- ActivityDesigner.cs
- BevelBitmapEffect.cs
- ThreadAttributes.cs
- SetIterators.cs
- IndicCharClassifier.cs
- EmptyEnumerator.cs
- Padding.cs
- GeneralTransform3DGroup.cs
- HttpApplicationStateBase.cs
- XmlElementList.cs
- securestring.cs
- CodeDomConfigurationHandler.cs
- ListViewItem.cs
- _UriSyntax.cs
- WindowsSpinner.cs
- EntityDataSourceWizardForm.cs
- BitmapDownload.cs
- WebPartTransformerCollection.cs
- DiscoveryDocumentReference.cs
- UriSection.cs
- InternalConfigEventArgs.cs
- DataListItem.cs
- MouseEvent.cs
- ToolStripItemEventArgs.cs
- URI.cs
- CodeChecksumPragma.cs
- CompModSwitches.cs
- SamlAuthorityBinding.cs
- ChannelSinkStacks.cs
- ChildChangedEventArgs.cs
- ConcurrencyMode.cs
- CapabilitiesUse.cs
- WebHttpEndpoint.cs
- _CookieModule.cs
- ImageKeyConverter.cs
- ActivityInfo.cs
- EasingKeyFrames.cs
- MetaTableHelper.cs
- SafeHandles.cs
- TimeZoneNotFoundException.cs
- TextRangeSerialization.cs
- DuplicateWaitObjectException.cs
- SelectiveScrollingGrid.cs
- TextSelectionHelper.cs
- FontUnitConverter.cs
- MultiTrigger.cs
- UIAgentCrashedException.cs
- ClientScriptManager.cs
- AttachedPropertyBrowsableForTypeAttribute.cs
- XmlStreamNodeWriter.cs
- CustomErrorCollection.cs
- WindowsFormsHostAutomationPeer.cs
- SrgsElementFactory.cs
- SplitterCancelEvent.cs
- CfgSemanticTag.cs
- MetadataPropertyCollection.cs
- Viewport3DVisual.cs
- Registry.cs
- TypeExtensionConverter.cs
- CodeAttachEventStatement.cs
- ExternalException.cs
- RegistryKey.cs
- SettingsPropertyValueCollection.cs
- CallContext.cs
- XmlDataLoader.cs
- ViewStateException.cs
- FreeFormDragDropManager.cs
- FontWeightConverter.cs
- XmlSchemaSimpleContentExtension.cs
- VisualBrush.cs
- SQLResource.cs
- QuadTree.cs
- User.cs
- WorkflowRuntimeService.cs
- DataGridComponentEditor.cs
- RequiredAttributeAttribute.cs
- DeploymentSection.cs
- ConfigsHelper.cs
- FormViewInsertEventArgs.cs
- Comparer.cs
- CrossContextChannel.cs
- linebase.cs
- ChannelSinkStacks.cs
- DesignerWidgets.cs
- StatusBar.cs
- StaticSiteMapProvider.cs