class/System.ComponentModel.Composition/src/ComponentModel/System/ComponentModel/Composition/Hosting/AggregateCatalog.cs

   1 // -----------------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 // -----------------------------------------------------------------------
   4 using System;
   5 using System.Collections.Generic;
   6 using System.ComponentModel.Composition.Primitives;
   7 using System.Globalization;
   8 using System.Linq;
   9 using System.Linq.Expressions;
  10 using System.Threading;
  11 using Microsoft.Internal;
  12
  13 namespace System.ComponentModel.Composition.Hosting
  14 {
  15     /// <summary>
  16     ///     A mutable collection of <see cref="ComposablePartCatalog"/>s.
  17     /// </summary>
  18     /// <remarks>
  19     ///     This type is thread safe.
  20     /// </remarks>
  21     public class AggregateCatalog : ComposablePartCatalog, INotifyComposablePartCatalogChanged
  22     {
  23         private ComposablePartCatalogCollection _catalogs = null;
  24         private volatile int _isDisposed = 0;
  25         private IQueryable<ComposablePartDefinition> _partsQuery;
  26
  27         /// <summary>
  28         ///     Initializes a new instance of the <see cref="AggregateCatalog"/> class.
  29         /// </summary>
  30         public AggregateCatalog()
  31             : this((IEnumerable<ComposablePartCatalog>)null)
  32         {
  33         }
  34
  35         /// <summary>
  36         ///     Initializes a new instance of the <see cref="AggregateCatalog"/> class
  37         ///     with the specified catalogs.
  38         /// </summary>
  39         /// <param name="catalogs">
  40         ///     An <see cref="Array"/> of <see cref="ComposablePartCatalog"/> objects to add to the
  41         ///     <see cref="AggregateCatalog"/>.
  42         /// </param>
  43         /// <exception cref="ArgumentNullException">
  44         ///     <paramref name="catalogs"/> is <see langword="null"/>.
  45         /// </exception>
  46         /// <exception cref="ArgumentException">
  47         ///     <paramref name="catalogs"/> contains an element that is <see langword="null"/>.
  48         /// </exception>
  49         public AggregateCatalog(params ComposablePartCatalog[] catalogs)
  50             : this((IEnumerable<ComposablePartCatalog>)catalogs)
  51         {
  52         }
  53
  54         /// <summary>
  55         ///     Initializes a new instance of the <see cref="AggregateCatalog"/> class
  56         ///     with the specified catalogs.
  57         /// </summary>
  58         /// <param name="catalogs">
  59         ///     An <see cref="IEnumerable{T}"/> of <see cref="ComposablePartCatalog"/> objects to add
  60         ///     to the <see cref="AggregateCatalog"/>; or <see langword="null"/> to
  61         ///     create an <see cref="AggregateCatalog"/> that is empty.
  62         /// </param>
  63         /// <exception cref="ArgumentException">
  64         ///     <paramref name="catalogs"/> contains an element that is <see langword="null"/>.
  65         /// </exception>
  66         public AggregateCatalog(IEnumerable<ComposablePartCatalog> catalogs)
  67         {
  68             Requires.NullOrNotNullElements(catalogs, "catalogs");
  69
  70             this._catalogs = new ComposablePartCatalogCollection(catalogs, this.OnChanged, this.OnChanging);
  71             this._partsQuery = this._catalogs.AsQueryable().SelectMany(catalog => catalog.Parts);
  72         }
  73
  74         /// <summary>
  75         /// Notify when the contents of the Catalog has changed.
  76         /// </summary>
  77         public event EventHandler<ComposablePartCatalogChangeEventArgs> Changed
  78         {
  79             add
  80             {
  81                 this._catalogs.Changed += value;
  82             }
  83             remove
  84             {
  85                 this._catalogs.Changed -= value;
  86             }
  87         }
  88
  89         /// <summary>
  90         /// Notify when the contents of the Catalog has changing.
  91         /// </summary>
  92         public event EventHandler<ComposablePartCatalogChangeEventArgs> Changing
  93         {
  94             add
  95             {
  96                 this._catalogs.Changing += value;
  97             }
  98             remove
  99             {
 100                 this._catalogs.Changing -= value;
 101             }
 102         }
 103
 104         /// <summary>
 105         ///     Gets the part definitions of the catalog.
 106         /// </summary>
 107         /// <value>
 108         ///     A <see cref="IQueryable{T}"/> of <see cref="ComposablePartDefinition"/> objects of the
 109         ///     <see cref="AggregateCatalog"/>.
 110         /// </value>
 111         /// <exception cref="ObjectDisposedException">
 112         ///     The <see cref="AggregateCatalog"/> has been disposed of.
 113         /// </exception>
 114         public override IQueryable<ComposablePartDefinition> Parts
 115         {
 116             get
 117             {
 118                 this.ThrowIfDisposed();
 119                 return this._partsQuery;
 120             }
 121         }
 122
 123         /// <summary>
 124         ///     Returns the export definitions that match the constraint defined by the specified definition.
 125         /// </summary>
 126         /// <param name="definition">
 127         ///     The <see cref="ImportDefinition"/> that defines the conditions of the
 128         ///     <see cref="ExportDefinition"/> objects to return.
 129         /// </param>
 130         /// <returns>
 131         ///     An <see cref="IEnumerable{T}"/> of <see cref="Tuple{T1, T2}"/> containing the
 132         ///     <see cref="ExportDefinition"/> objects and their associated
 133         ///     <see cref="ComposablePartDefinition"/> for objects that match the constraint defined
 134         ///     by <paramref name="definition"/>.
 135         /// </returns>
 136         /// <exception cref="ArgumentNullException">
 137         ///     <paramref name="definition"/> is <see langword="null"/>.
 138         /// </exception>
 139         /// <exception cref="ObjectDisposedException">
 140         ///     The <see cref="AggregateCatalog"/> has been disposed of.
 141         /// </exception>
 142         public override IEnumerable<Tuple<ComposablePartDefinition, ExportDefinition>> GetExports(ImportDefinition definition)
 143         {
 144             this.ThrowIfDisposed();
 145
 146             Requires.NotNull(definition, "definition");
 147
 148             // delegate the query to each catalog and merge the results.
 149             var exports = new List<Tuple<ComposablePartDefinition, ExportDefinition>>();
 150             foreach (var catalog in this._catalogs)
 151             {
 152                 foreach (var export in catalog.GetExports(definition))
 153                 {
 154                     exports.Add(export);
 155                 }
 156             }
 157             return exports;
 158         }
 159
 160         /// <summary>
 161         ///     Gets the underlying catalogs of the catalog.
 162         /// </summary>
 163         /// <value>
 164         ///     An <see cref="ICollection{T}"/> of underlying <see cref="ComposablePartCatalog"/> objects
 165         ///     of the <see cref="AggregateCatalog"/>.
 166         /// </value>
 167         /// <exception cref="ObjectDisposedException">
 168         ///     The <see cref="AggregateCatalog"/> has been disposed of.
 169         /// </exception>
 170         public ICollection<ComposablePartCatalog> Catalogs
 171         {
 172             get
 173             {
 174                 this.ThrowIfDisposed();
 175                 return this._catalogs;
 176             }
 177         }
 178
 179         protected override void Dispose(bool disposing)
 180         {
 181             try
 182             {
 183                 if (disposing)
 184                 {
 185                     // NOTE : According to http://msdn.microsoft.com/en-us/library/4bw5ewxy.aspx, the warning is bogus when used with Interlocked API.
 186 #pragma warning disable 420
 187                     if (Interlocked.CompareExchange(ref this._isDisposed, 1, 0) == 0)
 188 #pragma warning restore 420
 189                     {
 190                         this._catalogs.Dispose();
 191                     }
 192                 }
 193             }
 194             finally
 195             {
 196                 base.Dispose(disposing);
 197             }
 198         }
 199
 200         /// <summary>
 201         ///     Raises the <see cref="INotifyComposablePartCatalogChanged.Changed"/> event.
 202         /// </summary>
 203         /// <param name="e">
 204         ///     An <see cref="ComposablePartCatalogChangeEventArgs"/> containing the data for the event.
 205         /// </param>
 206         protected virtual void OnChanged(ComposablePartCatalogChangeEventArgs e)
 207         {
 208             this._catalogs.OnChanged(this, e);
 209         }
 210
 211         /// <summary>
 212         ///     Raises the <see cref="INotifyComposablePartCatalogChanged.Changing"/> event.
 213         /// </summary>
 214         /// <param name="e">
 215         ///     An <see cref="ComposablePartCatalogChangeEventArgs"/> containing the data for the event.
 216         /// </param>
 217         protected virtual void OnChanging(ComposablePartCatalogChangeEventArgs e)
 218         {
 219             this._catalogs.OnChanging(this, e);
 220         }
 221
 222         private void ThrowIfDisposed()
 223         {
 224             if (this._isDisposed == 1)
 225             {
 226                 throw ExceptionBuilder.CreateObjectDisposed(this);
 227             }
 228         }
 229     }
 230 }