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         [TypeConverterAttribute (typeof (ConstraintConverter))]
  50         public abstract class Constraint {
  51                 static readonly object beforeConstraintNameChange = new object ();
  52
  53                 EventHandlerList events = new EventHandlerList ();
  54
  55                 internal event DelegateConstraintNameChange BeforeConstraintNameChange {
  56                         add { events.AddHandler (beforeConstraintNameChange, value); }
  57                         remove { events.RemoveHandler (beforeConstraintNameChange, value); }
  58                 }
  59
  60                 //if constraintName is not set then a name is
  61                 //created when it is added to
  62                 //the ConstraintCollection
  63                 //it can not be set to null, empty or duplicate
  64                 //once it has been added to the collection
  65                 private string _constraintName;
  66                 private PropertyCollection _properties;
  67
  68                 private Index _index;
  69
  70                 //Used for membership checking
  71                 private ConstraintCollection _constraintCollection;
  72
  73                 DataSet dataSet;
  74
  75                 protected Constraint ()
  76                 {
  77                         dataSet = null;
  78                         _properties = new PropertyCollection ();
  79                 }
  80
  81                 [CLSCompliant (false)]
  82                 protected internal virtual DataSet _DataSet {
  83                         get { return dataSet; }
  84                 }
  85
  86                 [DataCategory ("Data")]
  87                 [DefaultValue ("")]
  88                 public virtual string ConstraintName {
  89                         get { return _constraintName == null ? "" : _constraintName; }
  90                         set {
  91                                 //This should only throw an exception when it
  92                                 //is a member of a ConstraintCollection which
  93                                 //means we should let the ConstraintCollection
  94                                 //handle exceptions when this value changes
  95                                 _onConstraintNameChange (value);
  96                                 _constraintName = value;
  97                         }
  98                 }
  99
 100                 [Browsable (false)]
 101                 [DataCategory ("Data")]
 102                 public PropertyCollection ExtendedProperties {
 103                         get { return _properties; }
 104                 }
 105
 106                 public abstract DataTable Table {
 107                         get;
 108                 }
 109
 110                 internal ConstraintCollection ConstraintCollection {
 111                         get { return _constraintCollection; }
 112                         set { _constraintCollection = value; }
 113                 }
 114
 115                 private void _onConstraintNameChange (string newName)
 116                 {
 117                         DelegateConstraintNameChange eh = events [beforeConstraintNameChange] as DelegateConstraintNameChange;
 118                         if (eh != null)
 119                                 eh (this, newName);
 120                 }
 121
 122                 //call once before adding a constraint to a collection
 123                 //will throw an exception to prevent the add if a rule is broken
 124                 internal abstract void AddToConstraintCollectionSetup (ConstraintCollection collection);
 125
 126                 internal abstract bool IsConstraintViolated ();
 127
 128                 internal static void ThrowConstraintException ()
 129                 {
 130                         throw new ConstraintException("Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.");
 131                 }
 132
 133                 bool initInProgress = false;
 134                 internal virtual bool InitInProgress {
 135                         get { return initInProgress; }
 136                         set { initInProgress = value; }
 137                 }
 138
 139                 internal virtual void FinishInit (DataTable table)
 140                 {
 141                 }
 142
 143                 internal void AssertConstraint ()
 144                 {
 145                         // The order is important.. IsConstraintViolated fills the RowErrors if it detects
 146                         // a violation
 147                         if (!IsConstraintViolated ())
 148                                 return;
 149                         if (Table._duringDataLoad || (Table.DataSet != null && !Table.DataSet.EnforceConstraints))
 150                                 return;
 151                         ThrowConstraintException ();
 152                 }
 153
 154                 internal abstract void AssertConstraint (DataRow row);
 155
 156                 internal virtual void RollbackAssert (DataRow row)
 157                 {
 158                 }
 159
 160                 //call once before removing a constraint to a collection
 161                 //can throw an exception to prevent the removal
 162                 internal abstract void RemoveFromConstraintCollectionCleanup (ConstraintCollection collection);
 163
 164                 [MonoTODO]
 165                 protected void CheckStateForProperty ()
 166                 {
 167                         throw new NotImplementedException ();
 168                 }
 169
 170                 protected internal void SetDataSet (DataSet dataSet)
 171                 {
 172                         this.dataSet = dataSet;
 173                 }
 174
 175                 internal void SetExtendedProperties (PropertyCollection properties)
 176                 {
 177                         _properties = properties;
 178                 }
 179
 180                 internal Index Index {
 181                         get { return _index; }
 182                         set {
 183                                 if (_index != null) {
 184                                         _index.RemoveRef();
 185                                         Table.DropIndex(_index);
 186                                 }
 187
 188                                 _index = value;
 189
 190                                 if (_index != null)
 191                                         _index.AddRef();
 192                         }
 193                 }
 194
 195                 internal abstract bool IsColumnContained (DataColumn column);
 196                 internal abstract bool CanRemoveFromCollection (ConstraintCollection col, bool shouldThrow);
 197
 198                 /// <summary>
 199                 /// Gets the ConstraintName, if there is one, as a string.
 200                 /// </summary>
 201                 public override string ToString ()
 202                 {
 203                         return _constraintName == null ? "" : _constraintName;
 204                 }
 205         }
 206 }