001/* Caret.java --
002   Copyright (C) 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.swing.text;
040
041import java.awt.Graphics;
042import java.awt.Point;
043
044import javax.swing.event.ChangeListener;
045
046/**
047 * Defines the method to be implemented by a caret that can be used in Swing
048 * text components.
049 *
050 * @author original author unknown
051 * @author Roman Kennke (roman@kennke.org)
052 */
053public interface Caret
054{
055  /**
056   * Registers a {@link ChangeListener} that is notified whenever that state
057   * of this <code>Caret</code> changes.
058   *
059   * @param l the listener to register to this caret
060   */
061  void addChangeListener(ChangeListener l);
062
063  /**
064   * Removes a {@link ChangeListener} from the list of registered listeners.
065   *
066   * @param l the listener to remove
067   */
068  void removeChangeListener(ChangeListener l);
069
070  /**
071   * Installs this <code>Caret</code> on the specified text component. This
072   * usually involves setting up listeners.
073   *
074   * This method is called by {@link JTextComponent#setCaret(Caret)} after
075   * this caret has been set on the text component.
076   *
077   * @param c the text component to install this caret to
078   */
079  void install(JTextComponent c);
080
081  /**
082   * Deinstalls this <code>Caret</code> from the specified text component.
083   * This usually involves removing listeners from the text component.
084   *
085   * This method is called by {@link JTextComponent#setCaret(Caret)} before
086   * this caret is removed from the text component.
087   *
088   * @param c the text component to deinstall this caret from
089   */
090  void deinstall(JTextComponent c);
091
092  /**
093   * Returns the blink rate of this <code>Caret</code> in milliseconds.
094   * A value of <code>0</code> means that the caret does not blink.
095   *
096   * @return the blink rate of this <code>Caret</code> or <code>0</code> if
097   *         this caret does not blink
098   */
099  int getBlinkRate();
100
101  /**
102   * Sets the blink rate of this <code>Caret</code> in milliseconds.
103   * A value of <code>0</code> means that the caret does not blink.
104   *
105   * @param rate the new blink rate to set
106   */
107  void setBlinkRate(int rate);
108
109  /**
110   * Returns the current position of this <code>Caret</code> within the
111   * <code>Document</code>.
112   *
113   * @return the current position of this <code>Caret</code> within the
114   *         <code>Document</code>
115   */
116  int getDot();
117
118  /**
119   * Sets the current position of this <code>Caret</code> within the
120   * <code>Document</code>. This also sets the <code>mark</code> to the
121   * new location.
122   *
123   * @param dot the new position to be set
124   *
125   * @see #moveDot(int)
126   */
127  void setDot(int dot);
128
129  /**
130   * Moves the <code>dot</code> location without touching the
131   * <code>mark</code>. This is used when making a selection.
132   *
133   * @param dot the location where to move the dot
134   *
135   * @see #setDot(int)
136   */
137  void moveDot(int dot);
138
139  /**
140   * Returns the current position of the <code>mark</code>. The
141   * <code>mark</code> marks the location in the <code>Document</code> that
142   * is the end of a selection. If there is no selection, the <code>mark</code>
143   * is the same as the <code>dot</code>.
144   *
145   * @return the current position of the mark
146   */
147  int getMark();
148
149  /**
150   * Returns the current visual position of this <code>Caret</code>.
151   *
152   * @return the current visual position of this <code>Caret</code>
153   *
154   * @see #setMagicCaretPosition
155   */
156  Point getMagicCaretPosition();
157
158  /**
159   * Sets the current visual position of this <code>Caret</code>.
160   *
161   * @param p the Point to use for the saved location. May be <code>null</code>
162   *        to indicate that there is no visual location
163   */
164  void setMagicCaretPosition(Point p);
165
166  /**
167   * Returns <code>true</code> if the selection is currently visible,
168   * <code>false</code> otherwise.
169   *
170   * @return <code>true</code> if the selection is currently visible,
171   *         <code>false</code> otherwise
172   */
173  boolean isSelectionVisible();
174
175  /**
176   * Sets the visiblity state of the selection.
177   *
178   * @param v <code>true</code> if the selection should be visible,
179   *        <code>false</code> otherwise
180   */
181  void setSelectionVisible(boolean v);
182
183  /**
184   * Returns <code>true</code> if this <code>Caret</code> is currently visible,
185   * and <code>false</code> if it is not.
186   *
187   * @return <code>true</code> if this <code>Caret</code> is currently visible,
188   *         and <code>false</code> if it is not
189   */
190  boolean isVisible();
191
192  /**
193   * Sets the visibility state of the caret. <code>true</code> shows the
194   * <code>Caret</code>, <code>false</code> hides it.
195   *
196   * @param v the visibility to set
197   */
198  void setVisible(boolean v);
199
200  /**
201   * Paints this <code>Caret</code> to the specified <code>Graphics</code>
202   * context.
203   *
204   * @param g the graphics context to render to
205   */
206  void paint(Graphics g);
207}