001    /* Caret.java -- 
002       Copyright (C) 2002, 2004, 2005 Free Software Foundation, Inc.
003    
004    This file is part of GNU Classpath.
005    
006    GNU Classpath is free software; you can redistribute it and/or modify
007    it under the terms of the GNU General Public License as published by
008    the Free Software Foundation; either version 2, or (at your option)
009    any later version.
010    
011    GNU Classpath is distributed in the hope that it will be useful, but
012    WITHOUT ANY WARRANTY; without even the implied warranty of
013    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014    General Public License for more details.
015    
016    You should have received a copy of the GNU General Public License
017    along with GNU Classpath; see the file COPYING.  If not, write to the
018    Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019    02110-1301 USA.
020    
021    Linking this library statically or dynamically with other modules is
022    making a combined work based on this library.  Thus, the terms and
023    conditions of the GNU General Public License cover the whole
024    combination.
025    
026    As a special exception, the copyright holders of this library give you
027    permission to link this library with independent modules to produce an
028    executable, regardless of the license terms of these independent
029    modules, and to copy and distribute the resulting executable under
030    terms of your choice, provided that you also meet, for each linked
031    independent module, the terms and conditions of the license of that
032    module.  An independent module is a module which is not derived from
033    or based on this library.  If you modify this library, you may extend
034    this exception to your version of the library, but you are not
035    obligated to do so.  If you do not wish to do so, delete this
036    exception statement from your version. */
037    
038    
039    package javax.swing.text;
040    
041    import java.awt.Graphics;
042    import java.awt.Point;
043    
044    import 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     */
053    public 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    }