/*
* Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package javax.swing;
import java.awt.*;
import java.awt.event.*;
/**
* Autoscroller is responsible for generating synthetic mouse dragged
* events. It is the responsibility of the Component (or its MouseListeners)
* that receive the events to do the actual scrolling in response to the
* mouse dragged events.
*
* @author Dave Moore
* @author Scott Violet
*/
class Autoscroller implements ActionListener {
/**
* Global Autoscroller.
*/
private static Autoscroller sharedInstance = new Autoscroller();
// As there can only ever be one autoscroller active these fields are
// static. The Timer is recreated as necessary to target the appropriate
// Autoscroller instance.
private static MouseEvent event;
private static Timer timer;
private static JComponent component;
//
// The public API, all methods are cover methods for an instance method
//
/**
* Stops autoscroll events from happening on the specified component.
*/
public static void stop(JComponent c) {
sharedInstance._stop(c);
}
/**
* Stops autoscroll events from happening on the specified component.
*/
public static boolean isRunning(JComponent c) {
return sharedInstance._isRunning(c);
}
/**
* Invoked when a mouse dragged event occurs, will start the autoscroller
* if necessary.
*/
public static void processMouseDragged(MouseEvent e) {
sharedInstance._processMouseDragged(e);
}
Autoscroller() {
}
/**
* Starts the timer targeting the passed in component.
*/
private void start(JComponent c, MouseEvent e) {
Point screenLocation = c.getLocationOnScreen();
if (component != c) {
_stop(component);
}
component = c;
event = new MouseEvent(component, e.getID(), e.getWhen(),
e.getModifiers(), e.getX() + screenLocation.x,
e.getY() + screenLocation.y,
e.getXOnScreen(),
e.getYOnScreen(),
e.getClickCount(), e.isPopupTrigger(),
MouseEvent.NOBUTTON);
if (timer == null) {
timer = new Timer(100, this);
}
if (!timer.isRunning()) {
timer.start();
}
}
//
// Methods mirror the public static API
//
/**
* Stops scrolling for the passed in widget.
*/
private void _stop(JComponent c) {
if (component == c) {
if (timer != null) {
timer.stop();
}
timer = null;
event = null;
component = null;
}
}
/**
* Returns true if autoscrolling is currently running for the specified
* widget.
*/
private boolean _isRunning(JComponent c) {
return (c == component && timer != null && timer.isRunning());
}
/**
* MouseListener method, invokes start/stop as necessary.
*/
private void _processMouseDragged(MouseEvent e) {
JComponent component = (JComponent)e.getComponent();
boolean stop = true;
if (component.isShowing()) {
Rectangle visibleRect = component.getVisibleRect();
stop = visibleRect.contains(e.getX(), e.getY());
}
if (stop) {
_stop(component);
} else {
start(component, e);
}
}
//
// ActionListener
//
/**
* ActionListener method. Invoked when the Timer fires. This will scroll
* if necessary.
*/
public void actionPerformed(ActionEvent x) {
JComponent component = Autoscroller.component;
if (component == null || !component.isShowing() || (event == null)) {
_stop(component);
return;
}
Point screenLocation = component.getLocationOnScreen();
MouseEvent e = new MouseEvent(component, event.getID(),
event.getWhen(), event.getModifiers(),
event.getX() - screenLocation.x,
event.getY() - screenLocation.y,
event.getXOnScreen(),
event.getYOnScreen(),
event.getClickCount(),
event.isPopupTrigger(),
MouseEvent.NOBUTTON);
component.superProcessMouseMotionEvent(e);
}
}