libjava/java/text/CharacterIterator.java

   1 /* CharacterIterator.java -- Iterate over a character range
   2    Copyright (C) 1998, 2001 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package java.text;
  40
  41 /**
  42   * This interface defines a mechanism for iterating over a range of
  43   * characters.  For a given range of text, a beginning and ending index,
  44   * as well as a current index are defined.  These values can be queried
  45   * by the methods in this interface.  Additionally, various methods allow
  46   * the index to be set.
  47   *
  48   * @version 0.0
  49   *
  50   * @author Aaron M. Renn (arenn@urbanophile.com)
  51   */
  52 public interface CharacterIterator extends Cloneable
  53 {
  54
  55   /*************************************************************************/
  56
  57   /*
  58    * Static Variables
  59    */
  60
  61   /**
  62    * This is a special constant value that is returned when the beginning or
  63    * end of the character range has been reached.
  64    */
  65   public static final char DONE = '\uFFFF';
  66
  67   /*************************************************************************/
  68
  69   /*
  70    * Instance Methods
  71    */
  72
  73   /**
  74    * This method returns the character at the current index position
  75    *
  76    * @return The character at the current index position.
  77    */
  78   public abstract char current ();
  79
  80   /*************************************************************************/
  81
  82   /**
  83    * This method increments the current index and then returns the character
  84    * at the new index value.  If the index is already at <code>getEndIndex() - 1</code>,
  85    * it will not be incremented.
  86    *
  87    * @return The character at the position of the incremented index value, or <code>DONE</code> if the index has reached getEndIndex() - 1
  88    */
  89   public abstract char next ();
  90
  91   /*************************************************************************/
  92
  93   /**
  94    * This method decrements the current index and then returns the character
  95    * at the new index value.  If the index value is already at the beginning
  96    * index, it will not be decremented.
  97    *
  98    * @return The character at the position of the decremented index value, or <code>DONE</code> if index was already equal to the beginning index value.
  99    */
 100   public abstract char previous ();
 101
 102   /*************************************************************************/
 103
 104   /**
 105    * This method sets the index value to the beginning of the range and returns
 106    * the character there.
 107    *
 108    * @return The character at the beginning of the range, or <code>DONE</code> if the range is empty.
 109    */
 110   public abstract char first ();
 111
 112   /*************************************************************************/
 113
 114   /**
 115    * This method sets the index value to <code>getEndIndex() - 1</code> and
 116    * returns the character there.  If the range is empty, then the index value
 117    * will be set equal to the beginning index.
 118    *
 119    * @return The character at the end of the range, or <code>DONE</code> if the range is empty.
 120    */
 121   public abstract char last ();
 122
 123   /*************************************************************************/
 124
 125   /**
 126    * This method returns the current value of the index.
 127    *
 128    * @return The current index value
 129    */
 130   public abstract int getIndex ();
 131
 132   /*************************************************************************/
 133
 134   /**
 135    * This method sets the value of the index to the specified value, then
 136    * returns the character at that position.
 137    *
 138    * @param index The new index value.
 139    *
 140    * @return The character at the new index value or <code>DONE</code> if the index value is equal to <code>getEndIndex</code>.
 141    */
 142   public abstract char setIndex (int index) throws IllegalArgumentException;
 143
 144   /*************************************************************************/
 145
 146   /**
 147    * This method returns the character position of the first character in the
 148    * range.
 149    *
 150    * @return The index of the first character in the range.
 151    */
 152   public abstract int getBeginIndex ();
 153
 154   /*************************************************************************/
 155
 156   /**
 157    * This method returns the character position of the end of the text range.
 158    * This will actually be the index of the first character following the
 159    * end of the range.  In the event the text range is empty, this will be
 160    * equal to the first character in the range.
 161    *
 162    * @return The index of the end of the range.
 163    */
 164   public abstract int getEndIndex ();
 165
 166   /*************************************************************************/
 167
 168   /**
 169    * This method creates a copy of this <code>CharacterIterator</code>.
 170    *
 171    * @return A copy of this <code>CharacterIterator</code>.
 172    */
 173   public abstract Object clone ();
 174 }