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	/*
	* 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.*;

	import sun.awt.AWTAccessor;
	import sun.awt.AWTAccessor.MouseEventAccessor;

	/**
	* 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);
	MouseEventAccessor meAccessor = AWTAccessor.getMouseEventAccessor();
	meAccessor.setCausedByTouchEvent(event,
	meAccessor.isCausedByTouchEvent(e));

	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);
	MouseEventAccessor meAccessor = AWTAccessor.getMouseEventAccessor();
	meAccessor.setCausedByTouchEvent(e,
	meAccessor.isCausedByTouchEvent(event));
	component.superProcessMouseMotionEvent(e);
	}

	}

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