Source for java.text.CharacterIterator

   1: /* CharacterIterator.java -- Iterate over a character range
   2:    Copyright (C) 1998, 2001, 2005 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., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 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:   * @author Aaron M. Renn (arenn@urbanophile.com)
  49:   */
  50: public interface CharacterIterator extends Cloneable
  51: {
  52:   /**
  53:    * This is a special constant value that is returned when the beginning or
  54:    * end of the character range has been reached.
  55:    */
  56:   char DONE = '\uFFFF';
  57: 
  58:   /**
  59:    * This method returns the character at the current index position
  60:    *
  61:    * @return The character at the current index position.
  62:    */
  63:   char current();
  64: 
  65:   /**
  66:    * This method increments the current index and then returns the character
  67:    * at the new index value.  If the index is already at 
  68:    * <code>getEndIndex() - 1</code>, it will not be incremented.
  69:    *
  70:    * @return The character at the position of the incremented index value,
  71:    * or {@link #DONE} if the index has reached getEndIndex() - 1
  72:    */
  73:   char next();
  74: 
  75:   /**
  76:    * This method decrements the current index and then returns the character
  77:    * at the new index value.  If the index value is already at the beginning
  78:    * index, it will not be decremented.
  79:    *
  80:    * @return The character at the position of the decremented index value,
  81:    *         or {@link #DONE} if index was already equal to the beginning index
  82:    *         value.
  83:    */
  84:   char previous();
  85: 
  86:   /**
  87:    * This method sets the index value to the beginning of the range and returns
  88:    * the character there.
  89:    *
  90:    * @return The character at the beginning of the range, or {@link #DONE} if 
  91:    *         the range is empty.
  92:    */
  93:   char first();
  94: 
  95:   /**
  96:    * This method sets the index value to <code>getEndIndex() - 1</code> and
  97:    * returns the character there.  If the range is empty, then the index value
  98:    * will be set equal to the beginning index.
  99:    *
 100:    * @return The character at the end of the range, or {@link #DONE} if the 
 101:    *         range is empty.
 102:    */
 103:   char last();  
 104: 
 105:   /**
 106:    * This method returns the current value of the index.
 107:    *
 108:    * @return The current index value
 109:    */
 110:   int getIndex();
 111: 
 112:   /**
 113:    * This method sets the value of the index to the specified value, then
 114:    * returns the character at that position.
 115:    *
 116:    * @param index The new index value.
 117:    *
 118:    * @return The character at the new index value or {@link #DONE} if the index
 119:    *         value is equal to {@link #getEndIndex()}.
 120:    */
 121:   char setIndex (int index) throws IllegalArgumentException;
 122: 
 123:   /**
 124:    * This method returns the character position of the first character in the
 125:    * range.
 126:    *
 127:    * @return The index of the first character in the range.
 128:    */
 129:   int getBeginIndex();
 130: 
 131:   /**
 132:    * This method returns the character position of the end of the text range.
 133:    * This will actually be the index of the first character following the
 134:    * end of the range.  In the event the text range is empty, this will be
 135:    * equal to the first character in the range.
 136:    *
 137:    * @return The index of the end of the range.
 138:    */
 139:   int getEndIndex();
 140: 
 141:   /**
 142:    * This method creates a copy of this <code>CharacterIterator</code>.
 143:    *
 144:    * @return A copy of this <code>CharacterIterator</code>.
 145:    */
 146:   Object clone();
 147: 
 148: } // interface CharacterIterator