libjava/java/text/StringCharacterIterator.java

   1 // StringCharacterIterator.java - Iterate over string of Unicode characters.
   2
   3 /* Copyright (C) 1999, 2000  Free Software Foundation
   4
   5    This file is part of libgcj.
   6
   7 This software is copyrighted work licensed under the terms of the
   8 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
   9 details.  */
  10
  11 package java.text;
  12
  13 /**
  14  * @author Tom Tromey <tromey@cygnus.com>
  15  * @date February 22, 1999
  16  */
  17 /* Written using "Java Class Libraries", 2nd edition, plus online
  18  * API docs for JDK 1.2 beta from http://www.javasoft.com.
  19  * Status:  Believed complete and correct to 1.1.
  20  */
  21
  22 public final class StringCharacterIterator implements CharacterIterator
  23 {
  24   public Object clone ()
  25   {
  26     return (Object) new StringCharacterIterator (text, begin, end, pos);
  27   }
  28
  29   public char current ()
  30   {
  31     // This follows JDK 1.2 semantics and not 1.1 semantics.
  32     // In 1.1 we would throw an exception if begin==end.
  33     return (pos < end) ? text.charAt(pos) : CharacterIterator.DONE;
  34   }
  35
  36   public boolean equals (Object obj)
  37   {
  38     if (! (obj instanceof StringCharacterIterator))
  39       return false;
  40     StringCharacterIterator sci = (StringCharacterIterator) obj;
  41     // The spec says "the same text".  We take this to mean equals,
  42     // not ==.
  43     return (pos == sci.pos
  44             && begin == sci.begin
  45             && end == sci.end
  46             && text.equals(sci.text));
  47   }
  48
  49   public char first ()
  50   {
  51     pos = begin;
  52     return current ();
  53   }
  54
  55   public int getBeginIndex ()
  56   {
  57     return begin;
  58   }
  59
  60   public int getEndIndex ()
  61   {
  62     return end;
  63   }
  64
  65   public int getIndex ()
  66   {
  67     return pos;
  68   }
  69
  70   public int hashCode ()
  71   {
  72     // FIXME: this is a terrible hash code.  Find a better one.
  73     return text.hashCode() + pos + begin + end;
  74   }
  75
  76   public char last ()
  77   {
  78     pos = end;
  79     return current ();
  80   }
  81
  82   public char next ()
  83   {
  84     if (pos == end)
  85       return CharacterIterator.DONE;
  86     ++pos;
  87     return current ();
  88   }
  89
  90   public char previous ()
  91   {
  92     if (pos == begin)
  93       return CharacterIterator.DONE;
  94     --pos;
  95     return current ();
  96   }
  97
  98   public char setIndex (int idx)
  99   {
 100     // In 1.1 we would throw an error if `idx == end'.
 101     if (idx < begin || idx > end)
 102       throw new IllegalArgumentException ();
 103     pos = idx;
 104     return current ();
 105   }
 106
 107   public StringCharacterIterator (String text)
 108   {
 109     this (text, 0, text.length(), 0);
 110   }
 111
 112   public StringCharacterIterator (String text, int pos)
 113   {
 114     this (text, 0, text.length(), pos);
 115   }
 116
 117   public StringCharacterIterator (String text, int begin, int end, int pos)
 118   {
 119     if (begin < 0 || begin > end || end > text.length()
 120         // In 1.1 we would also throw if `pos == end'.
 121         || pos < begin || pos > end)
 122       throw new IllegalArgumentException ();
 123
 124     this.text = text;
 125     this.begin = begin;
 126     this.end = end;
 127     this.pos = pos;
 128   }
 129
 130   // The online 1.2 docs say that this is "package visible" in the
 131   // method description, but they also say it is public.  We choose
 132   // the latter for compatibility with the actual implementation.
 133   public void setText (String text)
 134   {
 135     this.text = text;
 136     this.begin = 0;
 137     this.end = text.length ();
 138     this.pos = 0;
 139   }
 140
 141   // String to iterate over.
 142   private String text;
 143   // Current position.
 144   private int pos;
 145   // Start position in string.
 146   private int begin;
 147   // End position in string.
 148   private int end;
 149 }