mcs/class/System.XML/System.Xml.XPath/XPathNodeIterator.cs

   1 //
   2 // System.Xml.XPath.XPathNodeIterator
   3 //
   4 // Author:
   5 //   Jason Diamond (jason@injektilo.org)
   6 //
   7 // (C) 2002 Jason Diamond  http://injektilo.org/
   8 //
   9
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System;
  32 using System.Collections;
  33 #if NET_2_0
  34 using System.Diagnostics;
  35 #endif
  36
  37 namespace System.Xml.XPath
  38 {
  39 #if NET_2_0
  40         public abstract class XPathNodeIterator : ICloneable, IEnumerable
  41 #else
  42         public abstract class XPathNodeIterator : ICloneable
  43 #endif
  44         {
  45                 private int _count = -1;
  46
  47                 #region Constructor
  48
  49                 protected XPathNodeIterator ()
  50                 {
  51                 }
  52
  53                 #endregion
  54
  55                 #region Properties
  56
  57                 public virtual int Count
  58                 {
  59                         get
  60                         {
  61                                 if (_count == -1)
  62                                 {
  63                                         // compute and cache the count
  64                                         XPathNodeIterator tmp = Clone ();
  65                                         while (tmp.MoveNext ())
  66                                                 ;
  67                                         _count = tmp.CurrentPosition;
  68                                 }
  69                                 return _count;
  70                         }
  71                 }
  72
  73                 public abstract XPathNavigator Current { get; }
  74
  75                 public abstract int CurrentPosition { get; }
  76
  77                 #endregion
  78
  79                 #region Methods
  80
  81                 public abstract XPathNodeIterator Clone ();
  82
  83                 object ICloneable.Clone ()
  84                 {
  85                         return Clone ();
  86                 }
  87
  88 #if NET_2_0
  89                 public virtual IEnumerator GetEnumerator ()
  90                 {
  91                         return new XPathNodeIteratorEnumerator (this);
  92                 }
  93 #endif
  94
  95                 public abstract bool MoveNext ();
  96
  97                 #endregion
  98
  99                 struct XPathNodeIteratorEnumerator : IEnumerator
 100                 {
 101                         XPathNodeIterator source;
 102                         XPathNavigator current;
 103                         public XPathNodeIteratorEnumerator (XPathNodeIterator source)
 104                         {
 105                                 this.source = source.Clone ();
 106                                 current = null;
 107                         }
 108
 109                         public bool MoveNext ()
 110                         {
 111                                 if (!source.MoveNext ())
 112                                         return false;
 113                                 current = source.Current.Clone ();
 114                                 return true;
 115                         }
 116
 117                         public object Current {
 118                                 get { return current; }
 119                         }
 120
 121                         public void Reset ()
 122                         {
 123                                 throw new NotSupportedException ();
 124                         }
 125                 }
 126         }
 127 }