Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / fx / src / CompMod / System / Collections / Specialized / HybridDictionary.cs / 1 / HybridDictionary.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //----------------------------------------------------------------------------- namespace System.Collections.Specialized { using System.Collections; using System.Globalization; ////// [Serializable] public class HybridDictionary: IDictionary { // These numbers have been carefully tested to be optimal. Please don't change them // without doing thorough performance testing. private const int CutoverPoint = 9; private const int InitialHashtableSize = 13; private const int FixedSizeCutoverPoint = 6; // Instance variables. This keeps the HybridDictionary very light-weight when empty private ListDictionary list; private Hashtable hashtable; private bool caseInsensitive; ////// This data structure implements IDictionary first using a linked list /// (ListDictionary) and then switching over to use Hashtable when large. This is recommended /// for cases where the number of elements in a dictionary is unknown and might be small. /// /// It also has a single boolean parameter to allow case-sensitivity that is not affected by /// ambient culture and has been optimized for looking up case-insensitive symbols /// ////// public HybridDictionary() { } ///[To be supplied.] ////// public HybridDictionary(int initialSize) : this(initialSize, false) { } ///[To be supplied.] ////// public HybridDictionary(bool caseInsensitive) { this.caseInsensitive = caseInsensitive; } ///[To be supplied.] ////// public HybridDictionary(int initialSize, bool caseInsensitive) { this.caseInsensitive = caseInsensitive; if (initialSize >= FixedSizeCutoverPoint) { if (caseInsensitive) { hashtable = new Hashtable(initialSize, StringComparer.OrdinalIgnoreCase); } else { hashtable = new Hashtable(initialSize); } } } ///[To be supplied.] ////// public object this[object key] { get { //[To be supplied.] ///// Hashtable supports multiple read, one writer thread safety. // Although we never made the same guarantee for HybridDictionary, // it is still nice to do the same thing here since we have recommended // HybridDictioary as replacement for Hashtable. // // ListDictionary cachedList = list; if (hashtable != null) { return hashtable[key]; } else if (cachedList != null) { return cachedList[key]; } else { //// cachedList can be null in too cases: // (1) The dictionary is empty, we will return null in this case // (2) There is writer which is doing ChangeOver. However in that case // we should see the change to hashtable as well. // So it should work just fine. // // if (key == null) { throw new ArgumentNullException("key", SR.GetString(SR.ArgumentNull_Key)); } return null; } } set { if (hashtable != null) { hashtable[key] = value; } else if (list != null) { if (list.Count >= CutoverPoint - 1) { ChangeOver(); hashtable[key] = value; } else { list[key] = value; } } else { list = new ListDictionary(caseInsensitive ? StringComparer.OrdinalIgnoreCase : null); list[key] = value; } } } private ListDictionary List { get { if (list == null) { list = new ListDictionary(caseInsensitive ? StringComparer.OrdinalIgnoreCase : null); } return list; } } private void ChangeOver() { IDictionaryEnumerator en = list.GetEnumerator(); Hashtable newTable; if (caseInsensitive) { newTable = new Hashtable(InitialHashtableSize, StringComparer.OrdinalIgnoreCase); } else { newTable = new Hashtable(InitialHashtableSize); } while (en.MoveNext()) { newTable.Add(en.Key, en.Value); } //// Keep the order of writing to hashtable and list. // We assume we will see the change in hashtable if list is set to null in // this method in another reader thread. // hashtable = newTable; list = null; } ////// public int Count { get { ListDictionary cachedList = list; if (hashtable != null) { return hashtable.Count; } else if (cachedList != null) { return cachedList.Count; } else { return 0; } } } ///[To be supplied.] ////// public ICollection Keys { get { if (hashtable != null) { return hashtable.Keys; } else { return List.Keys; } } } ///[To be supplied.] ////// public bool IsReadOnly { get { return false; } } ///[To be supplied.] ////// public bool IsFixedSize { get { return false; } } ///[To be supplied.] ////// public bool IsSynchronized { get { return false; } } ///[To be supplied.] ////// public object SyncRoot { get { return this; } } ///[To be supplied.] ////// public ICollection Values { get { if (hashtable != null) { return hashtable.Values; } else { return List.Values; } } } ///[To be supplied.] ////// public void Add(object key, object value) { if (hashtable != null) { hashtable.Add(key, value); } else { if (list == null) { list = new ListDictionary(caseInsensitive ? StringComparer.OrdinalIgnoreCase : null); list.Add(key, value); } else { if (list.Count + 1 >= CutoverPoint) { ChangeOver(); hashtable.Add(key, value); } else { list.Add(key, value); } } } } ///[To be supplied.] ////// public void Clear() { if(hashtable != null) { Hashtable cachedHashtable = hashtable; hashtable = null; cachedHashtable.Clear(); } if( list != null) { ListDictionary cachedList = list; list = null; cachedList.Clear(); } } ///[To be supplied.] ////// public bool Contains(object key) { ListDictionary cachedList = list; if (hashtable != null) { return hashtable.Contains(key); } else if (cachedList != null) { return cachedList.Contains(key); } else { if (key == null) { throw new ArgumentNullException("key", SR.GetString(SR.ArgumentNull_Key)); } return false; } } ///[To be supplied.] ////// public void CopyTo(Array array, int index) { if (hashtable != null) { hashtable.CopyTo(array, index); } else { List.CopyTo(array, index); } } ///[To be supplied.] ////// public IDictionaryEnumerator GetEnumerator() { if (hashtable != null) { return hashtable.GetEnumerator(); } if (list == null) { list = new ListDictionary(caseInsensitive ? StringComparer.OrdinalIgnoreCase : null); } return list.GetEnumerator(); } ///[To be supplied.] ////// IEnumerator IEnumerable.GetEnumerator() { if (hashtable != null) { return hashtable.GetEnumerator(); } if (list == null) { list = new ListDictionary(caseInsensitive ? StringComparer.OrdinalIgnoreCase : null); } return list.GetEnumerator(); } ///[To be supplied.] ////// public void Remove(object key) { if (hashtable != null) { hashtable.Remove(key); } else if (list != null){ list.Remove(key); } else { if (key == null) { throw new ArgumentNullException("key", SR.GetString(SR.ArgumentNull_Key)); } } } } }[To be supplied.] ///
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- ToolStripDropDownButton.cs
- FunctionImportElement.cs
- smtpconnection.cs
- LocatorPart.cs
- FontNamesConverter.cs
- DateTimeEditor.cs
- XmlStreamStore.cs
- TemplateField.cs
- SqlInternalConnectionSmi.cs
- SynchronizedDispatch.cs
- RuleCache.cs
- DataGridTextColumn.cs
- PropertyValueEditor.cs
- COM2DataTypeToManagedDataTypeConverter.cs
- Directory.cs
- FrameworkObject.cs
- GenerateTemporaryAssemblyTask.cs
- NamedPipeWorkerProcess.cs
- XmlDataSourceView.cs
- AutomationPattern.cs
- ParenthesizePropertyNameAttribute.cs
- XmlDocumentSurrogate.cs
- ContentElementAutomationPeer.cs
- X509AudioLogo.cs
- SubpageParaClient.cs
- DelegateBodyWriter.cs
- ProjectedSlot.cs
- HostingPreferredMapPath.cs
- QfeChecker.cs
- EventHandlerList.cs
- XhtmlBasicListAdapter.cs
- RoleServiceManager.cs
- WebEventTraceProvider.cs
- GeneralTransform3D.cs
- ObjectTag.cs
- Stopwatch.cs
- CookieParameter.cs
- _PooledStream.cs
- GiveFeedbackEvent.cs
- DetailsViewModeEventArgs.cs
- InternalRelationshipCollection.cs
- IndexOutOfRangeException.cs
- TemplatingOptionsDialog.cs
- SqlNodeAnnotations.cs
- ThreadTrace.cs
- ColumnPropertiesGroup.cs
- AsmxEndpointPickerExtension.cs
- DetailsView.cs
- CommonGetThemePartSize.cs
- SystemWebSectionGroup.cs
- CryptoProvider.cs
- TableItemStyle.cs
- XmlnsDictionary.cs
- UnsafeNativeMethods.cs
- EnterpriseServicesHelper.cs
- StringAttributeCollection.cs
- DataMemberAttribute.cs
- DataListComponentEditor.cs
- ConfigurationSettings.cs
- ErrorWebPart.cs
- SQLDecimal.cs
- ModelPropertyImpl.cs
- VectorValueSerializer.cs
- TextEditorMouse.cs
- TimeSpanSecondsOrInfiniteConverter.cs
- NavigateEvent.cs
- SessionEndingCancelEventArgs.cs
- PartialList.cs
- TypeListConverter.cs
- control.ime.cs
- Highlights.cs
- TextEditorThreadLocalStore.cs
- MDIWindowDialog.cs
- SerializableTypeCodeDomSerializer.cs
- CrossContextChannel.cs
- ListDictionaryInternal.cs
- SerializationFieldInfo.cs
- UnicodeEncoding.cs
- XmlSchemaAppInfo.cs
- BaseValidator.cs
- EntityDataSourceView.cs
- NativeMethods.cs
- SerializableAttribute.cs
- PropertyReferenceSerializer.cs
- EdmTypeAttribute.cs
- ConnectionManagementSection.cs
- RouteCollection.cs
- RuleSet.cs
- MarkedHighlightComponent.cs
- ContentIterators.cs
- RoleManagerEventArgs.cs
- CustomValidator.cs
- RuleSettingsCollection.cs
- URLString.cs
- LogLogRecordEnumerator.cs
- ColumnReorderedEventArgs.cs
- KerberosSecurityTokenProvider.cs
- ScrollData.cs
- Assert.cs
- DataGridViewRowCancelEventArgs.cs