mcs/class/System.Data/System.Data/Constraint.cs

   1 //
   2 // System.Data.Constraint.cs
   3 //
   4 // Author:
   5 //      Franklin Wise <gracenote@earthlink.net>
   6 //      Daniel Morgan
   7 //      Tim Coleman (tim@timcoleman.com)
   8 //
   9 //
  10 // (C) Ximian, Inc. 2002
  11 // Copyright (C) Tim Coleman, 2002
  12 //
  13
  14 //
  15 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  16 //
  17 // Permission is hereby granted, free of charge, to any person obtaining
  18 // a copy of this software and associated documentation files (the
  19 // "Software"), to deal in the Software without restriction, including
  20 // without limitation the rights to use, copy, modify, merge, publish,
  21 // distribute, sublicense, and/or sell copies of the Software, and to
  22 // permit persons to whom the Software is furnished to do so, subject to
  23 // the following conditions:
  24 //
  25 // The above copyright notice and this permission notice shall be
  26 // included in all copies or substantial portions of the Software.
  27 //
  28 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  29 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  30 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  31 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  32 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  33 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  34 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  35 //
  36
  37 using System;
  38 using System.Collections;
  39 using System.ComponentModel;
  40 using System.Runtime.InteropServices;
  41 using System.Runtime.Serialization;
  42 using System.Data.Common;
  43
  44 namespace System.Data {
  45         [Serializable]
  46         internal delegate void DelegateConstraintNameChange (object sender, string newName);
  47
  48         [DefaultProperty ("ConstraintName")]
  49 #if !NET_2_0
  50         [Serializable]
  51 #endif
  52         [TypeConverterAttribute (typeof (ConstraintConverter))]
  53         public abstract class Constraint {
  54                 static readonly object beforeConstraintNameChange = new object ();
  55
  56                 EventHandlerList events = new EventHandlerList ();
  57
  58                 internal event DelegateConstraintNameChange BeforeConstraintNameChange {
  59                         add { events.AddHandler (beforeConstraintNameChange, value); }
  60                         remove { events.RemoveHandler (beforeConstraintNameChange, value); }
  61                 }
  62
  63                 //if constraintName is not set then a name is
  64                 //created when it is added to
  65                 //the ConstraintCollection
  66                 //it can not be set to null, empty or duplicate
  67                 //once it has been added to the collection
  68                 private string _constraintName;
  69                 private PropertyCollection _properties;
  70
  71                 private Index _index;
  72
  73                 //Used for membership checking
  74                 private ConstraintCollection _constraintCollection;
  75
  76                 DataSet dataSet;
  77
  78                 protected Constraint ()
  79                 {
  80                         dataSet = null;
  81                         _properties = new PropertyCollection ();
  82                 }
  83
  84                 [CLSCompliant (false)]
  85                 protected internal virtual DataSet _DataSet {
  86                         get { return dataSet; }
  87                 }
  88
  89                 [DataCategory ("Data")]
  90 #if !NET_2_0
  91                 [DataSysDescription ("Indicates the name of this constraint.")]
  92 #endif
  93                 [DefaultValue ("")]
  94                 public virtual string ConstraintName {
  95                         get { return _constraintName == null ? "" : _constraintName; }
  96                         set {
  97                                 //This should only throw an exception when it
  98                                 //is a member of a ConstraintCollection which
  99                                 //means we should let the ConstraintCollection
 100                                 //handle exceptions when this value changes
 101                                 _onConstraintNameChange (value);
 102                                 _constraintName = value;
 103                         }
 104                 }
 105
 106                 [Browsable (false)]
 107                 [DataCategory ("Data")]
 108 #if !NET_2_0
 109                 [DataSysDescription ("The collection that holds custom user information.")]
 110 #endif
 111                 public PropertyCollection ExtendedProperties {
 112                         get { return _properties; }
 113                 }
 114
 115 #if !NET_2_0
 116                 [DataSysDescription ("Indicates the table of this constraint.")]
 117 #endif
 118                 public abstract DataTable Table {
 119                         get;
 120                 }
 121
 122                 internal ConstraintCollection ConstraintCollection {
 123                         get { return _constraintCollection; }
 124                         set { _constraintCollection = value; }
 125                 }
 126
 127                 private void _onConstraintNameChange (string newName)
 128                 {
 129                         DelegateConstraintNameChange eh = events [beforeConstraintNameChange] as DelegateConstraintNameChange;
 130                         if (eh != null)
 131                                 eh (this, newName);
 132                 }
 133
 134                 //call once before adding a constraint to a collection
 135                 //will throw an exception to prevent the add if a rule is broken
 136                 internal abstract void AddToConstraintCollectionSetup (ConstraintCollection collection);
 137
 138                 internal abstract bool IsConstraintViolated ();
 139
 140                 internal static void ThrowConstraintException ()
 141                 {
 142                         throw new ConstraintException("Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.");
 143                 }
 144
 145                 bool initInProgress = false;
 146                 internal virtual bool InitInProgress {
 147                         get { return initInProgress; }
 148                         set { initInProgress = value; }
 149                 }
 150
 151                 internal virtual void FinishInit (DataTable table)
 152                 {
 153                 }
 154
 155                 internal void AssertConstraint ()
 156                 {
 157                         // The order is important.. IsConstraintViolated fills the RowErrors if it detects
 158                         // a violation
 159                         if (!IsConstraintViolated ())
 160                                 return;
 161                         if (Table._duringDataLoad || (Table.DataSet != null && !Table.DataSet.EnforceConstraints))
 162                                 return;
 163                         ThrowConstraintException ();
 164                 }
 165
 166                 internal abstract void AssertConstraint (DataRow row);
 167
 168                 internal virtual void RollbackAssert (DataRow row)
 169                 {
 170                 }
 171
 172                 //call once before removing a constraint to a collection
 173                 //can throw an exception to prevent the removal
 174                 internal abstract void RemoveFromConstraintCollectionCleanup (ConstraintCollection collection);
 175
 176                 [MonoTODO]
 177                 protected void CheckStateForProperty ()
 178                 {
 179                         throw new NotImplementedException ();
 180                 }
 181
 182                 protected internal void SetDataSet (DataSet dataSet)
 183                 {
 184                         this.dataSet = dataSet;
 185                 }
 186
 187                 internal void SetExtendedProperties (PropertyCollection properties)
 188                 {
 189                         _properties = properties;
 190                 }
 191
 192                 internal Index Index {
 193                         get { return _index; }
 194                         set {
 195                                 if (_index != null) {
 196                                         _index.RemoveRef();
 197                                         Table.DropIndex(_index);
 198                                 }
 199
 200                                 _index = value;
 201
 202                                 if (_index != null)
 203                                         _index.AddRef();
 204                         }
 205                 }
 206
 207                 internal abstract bool IsColumnContained (DataColumn column);
 208                 internal abstract bool CanRemoveFromCollection (ConstraintCollection col, bool shouldThrow);
 209
 210                 /// <summary>
 211                 /// Gets the ConstraintName, if there is one, as a string.
 212                 /// </summary>
 213                 public override string ToString ()
 214                 {
 215                         return _constraintName == null ? "" : _constraintName;
 216                 }
 217         }
 218 }