1/*
2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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24 */
25package javax.swing.text;
26
27import java.awt.Graphics;
28import java.awt.Point;
29import javax.swing.Action;
30import javax.swing.event.ChangeListener;
31
32/**
33 * A place within a document view that represents where
34 * things can be inserted into the document model.  A caret
35 * has a position in the document referred to as a dot.
36 * The dot is where the caret is currently located in the
37 * model.  There is
38 * a second position maintained by the caret that represents
39 * the other end of a selection called mark.  If there is
40 * no selection the dot and mark will be equal.  If a selection
41 * exists, the two values will be different.
42 * <p>
43 * The dot can be placed by either calling
44 * <code>setDot</code> or <code>moveDot</code>.  Setting
45 * the dot has the effect of removing any selection that may
46 * have previously existed.  The dot and mark will be equal.
47 * Moving the dot has the effect of creating a selection as
48 * the mark is left at whatever position it previously had.
49 *
50 * @author  Timothy Prinzing
51 */
52public interface Caret {
53
54    /**
55     * Called when the UI is being installed into the
56     * interface of a JTextComponent.  This can be used
57     * to gain access to the model that is being navigated
58     * by the implementation of this interface.
59     *
60     * @param c the JTextComponent
61     */
62    public void install(JTextComponent c);
63
64    /**
65     * Called when the UI is being removed from the
66     * interface of a JTextComponent.  This is used to
67     * unregister any listeners that were attached.
68     *
69     * @param c the JTextComponent
70     */
71    public void deinstall(JTextComponent c);
72
73    /**
74     * Renders the caret. This method is called by UI classes.
75     *
76     * @param g the graphics context
77     */
78    public void paint(Graphics g);
79
80    /**
81     * Adds a listener to track whenever the caret position
82     * has been changed.
83     *
84     * @param l the change listener
85     */
86    public void addChangeListener(ChangeListener l);
87
88    /**
89     * Removes a listener that was tracking caret position changes.
90     *
91     * @param l the change listener
92     */
93    public void removeChangeListener(ChangeListener l);
94
95    /**
96     * Determines if the caret is currently visible.
97     *
98     * @return true if the caret is visible else false
99     */
100    public boolean isVisible();
101
102    /**
103     * Sets the visibility of the caret.
104     *
105     * @param v  true if the caret should be shown,
106     *  and false if the caret should be hidden
107     */
108    public void setVisible(boolean v);
109
110    /**
111     * Determines if the selection is currently visible.
112     *
113     * @return true if the caret is visible else false
114     */
115    public boolean isSelectionVisible();
116
117    /**
118     * Sets the visibility of the selection
119     *
120     * @param v  true if the caret should be shown,
121     *  and false if the caret should be hidden
122     */
123    public void setSelectionVisible(boolean v);
124
125    /**
126     * Set the current caret visual location.  This can be used when
127     * moving between lines that have uneven end positions (such as
128     * when caret up or down actions occur).  If text flows
129     * left-to-right or right-to-left the x-coordinate will indicate
130     * the desired navigation location for vertical movement.  If
131     * the text flow is top-to-bottom, the y-coordinate will indicate
132     * the desired navigation location for horizontal movement.
133     *
134     * @param p  the Point to use for the saved position.  This
135     *   can be null to indicate there is no visual location.
136     */
137    public void setMagicCaretPosition(Point p);
138
139    /**
140     * Gets the current caret visual location.
141     *
142     * @return the visual position.
143     * @see #setMagicCaretPosition
144     */
145    public Point getMagicCaretPosition();
146
147    /**
148     * Sets the blink rate of the caret.  This determines if
149     * and how fast the caret blinks, commonly used as one
150     * way to attract attention to the caret.
151     *
152     * @param rate  the delay in milliseconds &gt;=0.  If this is
153     *  zero the caret will not blink.
154     */
155    public void setBlinkRate(int rate);
156
157    /**
158     * Gets the blink rate of the caret.  This determines if
159     * and how fast the caret blinks, commonly used as one
160     * way to attract attention to the caret.
161     *
162     * @return the delay in milliseconds &gt;=0.  If this is
163     *  zero the caret will not blink.
164     */
165    public int getBlinkRate();
166
167    /**
168     * Fetches the current position of the caret.
169     *
170     * @return the position &gt;=0
171     */
172    public int getDot();
173
174    /**
175     * Fetches the current position of the mark.  If there
176     * is a selection, the mark will not be the same as
177     * the dot.
178     *
179     * @return the position &gt;=0
180     */
181    public int getMark();
182
183    /**
184     * Sets the caret position to some position.  This
185     * causes the mark to become the same as the dot,
186     * effectively setting the selection range to zero.
187     * <p>
188     * If the parameter is negative or beyond the length of the document,
189     * the caret is placed at the beginning or at the end, respectively.
190     *
191     * @param dot  the new position to set the caret to
192     */
193    public void setDot(int dot);
194
195    /**
196     * Moves the caret position (dot) to some other position,
197     * leaving behind the mark.  This is useful for
198     * making selections.
199     *
200     * @param dot  the new position to move the caret to &gt;=0
201     */
202    public void moveDot(int dot);
203
204};
205