mcs/class/referencesource/System.Data.Entity/System/Data/Objects/RelationshipWrapper.cs

   1 //---------------------------------------------------------------------
   2 // <copyright file="RelationshipWrapper.cs" company="Microsoft">
   3 //      Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 //
   6 // @owner       Microsoft
   7 // @backupOwner Microsoft
   8 //---------------------------------------------------------------------
   9 using System;
  10 using System.Collections.Generic;
  11 using System.Diagnostics;
  12 using System.Data.Metadata.Edm;
  13
  14 namespace System.Data.Objects
  15 {
  16     internal sealed class RelationshipWrapper : IEquatable<RelationshipWrapper>
  17     {
  18         internal readonly AssociationSet AssociationSet;
  19         internal readonly EntityKey Key0;
  20         internal readonly EntityKey Key1;
  21
  22         internal RelationshipWrapper(AssociationSet extent, EntityKey key)
  23         {
  24             Debug.Assert(null != extent, "null RelationshipWrapper");
  25             Debug.Assert(null != (object)key, "null key");
  26
  27             this.AssociationSet = extent;
  28             this.Key0 = key;
  29             this.Key1 = key;
  30         }
  31
  32         internal RelationshipWrapper(RelationshipWrapper wrapper, int ordinal, EntityKey key)
  33         {
  34             Debug.Assert(null != wrapper, "null RelationshipWrapper");
  35             Debug.Assert((uint)ordinal <= 1u, "ordinal out of range");
  36             Debug.Assert(null != (object)key, "null key2");
  37
  38             this.AssociationSet = wrapper.AssociationSet;
  39             this.Key0 = (0 == ordinal) ? key : wrapper.Key0;
  40             this.Key1 = (0 == ordinal) ? wrapper.Key1 : key;
  41         }
  42
  43         internal RelationshipWrapper(AssociationSet extent,
  44                                      KeyValuePair<string, EntityKey> roleAndKey1,
  45                                      KeyValuePair<string, EntityKey> roleAndKey2)
  46             : this(extent, roleAndKey1.Key, roleAndKey1.Value, roleAndKey2.Key, roleAndKey2.Value)
  47         {
  48         }
  49
  50         internal RelationshipWrapper(AssociationSet extent,
  51                                      string role0, EntityKey key0,
  52                                      string role1, EntityKey key1)
  53         {
  54             Debug.Assert(null != extent, "null AssociationSet");
  55             Debug.Assert(null != (object)key0, "null key0");
  56             Debug.Assert(null != (object)key1, "null key1");
  57
  58             AssociationSet = extent;
  59             Debug.Assert(extent.ElementType.AssociationEndMembers.Count == 2, "only 2 ends are supported");
  60
  61             // this assert is explictly commented out to show that the two are similar but different
  62             // we should always use AssociationEndMembers, never CorrespondingAssociationEndMember
  63             //Debug.Assert(AssociationSet.AssociationSetEnds.Count == 2, "only 2 set ends supported");
  64             //Debug.Assert(extent.ElementType.AssociationEndMembers[0] == AssociationSet.AssociationSetEnds[0].CorrespondingAssociationEndMember, "should be same end member");
  65             //Debug.Assert(extent.ElementType.AssociationEndMembers[1] == AssociationSet.AssociationSetEnds[1].CorrespondingAssociationEndMember, "should be same end member");
  66
  67             if (extent.ElementType.AssociationEndMembers[0].Name == role0)
  68             {
  69                 Debug.Assert(extent.ElementType.AssociationEndMembers[1].Name == role1, "a)roleAndKey1 Name differs");
  70                 Key0 = key0;
  71                 Key1 = key1;
  72             }
  73             else
  74             {
  75                 Debug.Assert(extent.ElementType.AssociationEndMembers[0].Name == role1, "b)roleAndKey1 Name differs");
  76                 Debug.Assert(extent.ElementType.AssociationEndMembers[1].Name == role0, "b)roleAndKey0 Name differs");
  77                 Key0 = key1;
  78                 Key1 = key0;
  79             }
  80         }
  81
  82         internal ReadOnlyMetadataCollection<AssociationEndMember> AssociationEndMembers
  83         {
  84             get { return this.AssociationSet.ElementType.AssociationEndMembers; }
  85         }
  86
  87         internal AssociationEndMember GetAssociationEndMember(EntityKey key)
  88         {
  89             Debug.Assert(Key0 == key || Key1 == key, "didn't match a key");
  90             return AssociationEndMembers[(Key0 != key) ? 1 : 0];
  91         }
  92
  93         internal EntityKey GetOtherEntityKey(EntityKey key)
  94         {
  95             return ((Key0 == key) ? Key1 : ((Key1 == key) ? Key0 : null));
  96         }
  97
  98         internal EntityKey GetEntityKey(int ordinal)
  99         {
 100             switch (ordinal)
 101             {
 102                 case 0:
 103                     return Key0;
 104                 case 1:
 105                     return Key1;
 106                 default:
 107                     throw EntityUtil.ArgumentOutOfRange("ordinal");
 108             }
 109         }
 110
 111         public override int GetHashCode()
 112         {
 113             return this.AssociationSet.Name.GetHashCode() ^ (this.Key0.GetHashCode() + this.Key1.GetHashCode());
 114         }
 115
 116         public override bool Equals(object obj)
 117         {
 118             return Equals(obj as RelationshipWrapper);
 119         }
 120
 121         public bool Equals(RelationshipWrapper wrapper)
 122         {
 123             return (Object.ReferenceEquals(this, wrapper) ||
 124                     ((null != wrapper) &&
 125                      Object.ReferenceEquals(this.AssociationSet, wrapper.AssociationSet) &&
 126                      this.Key0.Equals(wrapper.Key0) &&
 127                      this.Key1.Equals(wrapper.Key1)));
 128         }
 129     }
 130 }