001/* AccessibleText.java -- aids in accessibly manipulating text
002   Copyright (C) 2000, 2002, 2004, 2005  Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
011GNU Classpath is distributed in the hope that it will be useful, but
012WITHOUT ANY WARRANTY; without even the implied warranty of
013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
016You should have received a copy of the GNU General Public License
017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038
039package javax.accessibility;
040
041import java.awt.Point;
042import java.awt.Rectangle;
043
044import javax.swing.text.AttributeSet;
045
046/**
047 * Objects which present textual information on the display should implement
048 * this interface.  Accessibility software can use the implementations of
049 * this interface to change the attributes and spacial location of the text.
050 *
051 * <p>The <code>AccessibleContext.getAccessibleText()</code> method
052 * should return <code>null</code> if an object does not implement this
053 * interface.
054 *
055 * @author Eric Blake (ebb9@email.byu.edu)
056 * @see Accessible
057 * @see AccessibleContext
058 * @see AccessibleContext#getAccessibleText()
059 * @since 1.2
060 * @status updated to 1.4
061 */
062public interface AccessibleText
063{
064  /**
065   * Constant designating that the next selection should be a character.
066   *
067   * @see #getAtIndex(int, int)
068   * @see #getAfterIndex(int, int)
069   * @see #getBeforeIndex(int, int)
070   */
071  int CHARACTER = 1;
072
073  /**
074   * Constant designating that the next selection should be a word.
075   *
076   * @see #getAtIndex(int, int)
077   * @see #getAfterIndex(int, int)
078   * @see #getBeforeIndex(int, int)
079   */
080  int WORD = 2;
081
082  /**
083   * Constant designating that the next selection should be a sentence.
084   *
085   * @see #getAtIndex(int, int)
086   * @see #getAfterIndex(int, int)
087   * @see #getBeforeIndex(int, int)
088   */
089  int SENTENCE = 3;
090
091  /**
092   * Given a point in the coordinate system of this object, return the
093   * 0-based index of the character at that point, or -1 if there is none.
094   *
095   * @param point the point to look at
096   * @return the character index, or -1
097   */
098  int getIndexAtPoint(Point point);
099
100  /**
101   * Determines the bounding box of the indexed character. Returns an empty
102   * rectangle if the index is out of bounds.
103   *
104   * @param index the 0-based character index
105   * @return the bounding box, may be empty
106   */
107  Rectangle getCharacterBounds(int index);
108
109  /**
110   * Return the number of characters.
111   *
112   * @return the character count
113   */
114  int getCharCount();
115
116  /**
117   * Return the offset of the character. The offset matches the index of the
118   * character to the right, since the carat lies between characters.
119   *
120   * @return the 0-based caret position
121   */
122  int getCaretPosition();
123
124  /**
125   * Returns the section of text at the index, or null if the index or part
126   * is invalid.
127   *
128   * @param part {@link #CHARACTER}, {@link #WORD}, or {@link #SENTENCE}
129   * @param index the 0-based character index
130   * @return the selection of text at that index, or null
131   */
132  String getAtIndex(int part, int index);
133
134  /**
135   * Returns the section of text after the index, or null if the index or part
136   * is invalid.
137   *
138   * @param part {@link #CHARACTER}, {@link #WORD}, or {@link #SENTENCE}
139   * @param index the 0-based character index
140   * @return the selection of text after that index, or null
141   */
142  String getAfterIndex(int part, int index);
143
144  /**
145   * Returns the section of text before the index, or null if the index or part
146   * is invalid.
147   *
148   * @param part {@link #CHARACTER}, {@link #WORD}, or {@link #SENTENCE}
149   * @param index the 0-based character index
150   * @return the selection of text before that index, or null
151   */
152  String getBeforeIndex(int part, int index);
153
154  /**
155   * Returns the attributes of a character at an index, or null if the index
156   * is out of bounds.
157   *
158   * @param index the 0-based character index
159   * @return the character's attributes
160   */
161  AttributeSet getCharacterAttribute(int index);
162
163  /**
164   * Returns the start index of the selection. If there is no selection, this
165   * is the same as the caret location.
166   *
167   * @return the 0-based character index of the selection start
168   */
169  int getSelectionStart();
170
171  /**
172   * Returns the end index of the selection. If there is no selection, this
173   * is the same as the caret location.
174   *
175   * @return the 0-based character index of the selection end
176   */
177  int getSelectionEnd();
178
179  /**
180   * Returns the selected text. This may be null or "" if no text is selected.
181   *
182   * @return the selected text
183   */
184  String getSelectedText();
185} // interface AccessibleText