1 /*
2 * Copyright (c) 1997, 2006, 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
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javax.swing;
27
28 import java.awt.*;
29 import java.awt.event.*;
30
31 import sun.awt.AWTAccessor;
32 import sun.awt.AWTAccessor.MouseEventAccessor;
33
34 /**
35 * Autoscroller is responsible for generating synthetic mouse dragged
36 * events. It is the responsibility of the Component (or its MouseListeners)
37 * that receive the events to do the actual scrolling in response to the
38 * mouse dragged events.
39 *
40 * @author Dave Moore
41 * @author Scott Violet
42 */
43 class Autoscroller implements ActionListener {
44 /**
45 * Global Autoscroller.
46 */
47 private static Autoscroller sharedInstance = new Autoscroller();
48
49 // As there can only ever be one autoscroller active these fields are
50 // static. The Timer is recreated as necessary to target the appropriate
51 // Autoscroller instance.
52 private static MouseEvent event;
53 private static Timer timer;
54 private static JComponent component;
55
56 //
57 // The public API, all methods are cover methods for an instance method
58 //
59 /**
60 * Stops autoscroll events from happening on the specified component.
61 */
62 public static void stop(JComponent c) {
63 sharedInstance._stop(c);
64 }
65
66 /**
67 * Stops autoscroll events from happening on the specified component.
68 */
69 public static boolean isRunning(JComponent c) {
70 return sharedInstance._isRunning(c);
71 }
72
73 /**
74 * Invoked when a mouse dragged event occurs, will start the autoscroller
75 * if necessary.
76 */
77 public static void processMouseDragged(MouseEvent e) {
78 sharedInstance._processMouseDragged(e);
79 }
80
81
82 Autoscroller() {
83 }
84
85 /**
86 * Starts the timer targeting the passed in component.
87 */
88 @SuppressWarnings("deprecation")
89 private void start(JComponent c, MouseEvent e) {
90 Point screenLocation = c.getLocationOnScreen();
91
92 if (component != c) {
93 _stop(component);
94 }
95 component = c;
96 event = new MouseEvent(component, e.getID(), e.getWhen(),
97 e.getModifiers(), e.getX() + screenLocation.x,
98 e.getY() + screenLocation.y,
99 e.getXOnScreen(),
100 e.getYOnScreen(),
101 e.getClickCount(), e.isPopupTrigger(),
102 MouseEvent.NOBUTTON);
103 MouseEventAccessor meAccessor = AWTAccessor.getMouseEventAccessor();
104 meAccessor.setCausedByTouchEvent(event,
105 meAccessor.isCausedByTouchEvent(e));
106
107 if (timer == null) {
108 timer = new Timer(100, this);
109 }
110
111 if (!timer.isRunning()) {
112 timer.start();
113 }
114 }
115
116 //
117 // Methods mirror the public static API
118 //
119
120 /**
121 * Stops scrolling for the passed in widget.
122 */
123 private void _stop(JComponent c) {
124 if (component == c) {
125 if (timer != null) {
126 timer.stop();
127 }
128 timer = null;
129 event = null;
130 component = null;
131 }
132 }
133
134 /**
135 * Returns true if autoscrolling is currently running for the specified
136 * widget.
137 */
138 private boolean _isRunning(JComponent c) {
139 return (c == component && timer != null && timer.isRunning());
140 }
141
142 /**
143 * MouseListener method, invokes start/stop as necessary.
144 */
145 private void _processMouseDragged(MouseEvent e) {
146 JComponent component = (JComponent)e.getComponent();
147 boolean stop = true;
148 if (component.isShowing()) {
149 Rectangle visibleRect = component.getVisibleRect();
150 stop = visibleRect.contains(e.getX(), e.getY());
151 }
152 if (stop) {
153 _stop(component);
154 } else {
155 start(component, e);
156 }
157 }
158
159 //
160 // ActionListener
161 //
162 /**
163 * ActionListener method. Invoked when the Timer fires. This will scroll
164 * if necessary.
165 */
166 @SuppressWarnings("deprecation")
167 public void actionPerformed(ActionEvent x) {
168 JComponent component = Autoscroller.component;
169
170 if (component == null || !component.isShowing() || (event == null)) {
171 _stop(component);
172 return;
173 }
174 Point screenLocation = component.getLocationOnScreen();
175 MouseEvent e = new MouseEvent(component, event.getID(),
176 event.getWhen(), event.getModifiers(),
177 event.getX() - screenLocation.x,
178 event.getY() - screenLocation.y,
179 event.getXOnScreen(),
180 event.getYOnScreen(),
181 event.getClickCount(),
182 event.isPopupTrigger(),
183 MouseEvent.NOBUTTON);
184 MouseEventAccessor meAccessor = AWTAccessor.getMouseEventAccessor();
185 meAccessor.setCausedByTouchEvent(e,
186 meAccessor.isCausedByTouchEvent(event));
187 component.superProcessMouseMotionEvent(e);
188 }
189
190 }