/*

 * Copyright 2003 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package java.awt;

import sun.security.util.SecurityConstants;

/**

 * <code>MouseInfo</code>  provides methods for getting information about the mouse,

 * such as mouse pointer location and the number of mouse buttons.

 *

 * @author     Roman Poborchiy

 * @since 1.5

 */

public class MouseInfo {

    /**

     * Private constructor to prevent instantiation.

     */

    private MouseInfo() {

    }

    /**

     * Returns a <code>PointerInfo</code> instance that represents the current

     * location of the mouse pointer.

     * The <code>GraphicsDevice</code> stored in this <code>PointerInfo</code>

     * contains the mouse pointer. The coordinate system used for the mouse position

     * depends on whether or not the <code>GraphicsDevice</code> is part of a virtual

     * screen device.

     * For virtual screen devices, the coordinates are given in the virtual

     * coordinate system, otherwise they are returned in the coordinate system

     * of the <code>GraphicsDevice</code>. See {@link GraphicsConfiguration}

     * for more information about the virtual screen devices.

     * On systems without a mouse, returns <code>null</code>.

     * <p>

     * If there is a security manager, its <code>checkPermission</code> method

     * is called with an <code>AWTPermission("watchMousePointer")</code>

     * permission before creating and returning a <code>PointerInfo</code>

     * object. This may result in a <code>SecurityException</code>.

     *

     * @exception HeadlessException if GraphicsEnvironment.isHeadless() returns true

     * @exception SecurityException if a security manager exists and its

     *            <code>checkPermission</code> method doesn't allow the operation

     * @see       GraphicsConfiguration

     * @see       SecurityManager#checkPermission

     * @see       java.awt.AWTPermission

     * @return    location of the mouse pointer

     * @since     1.5

     */

    public static PointerInfo getPointerInfo() throws HeadlessException {

        if (GraphicsEnvironment.isHeadless()) {

            throw new HeadlessException();

        }

        SecurityManager security = System.getSecurityManager();

        if (security != null) {

            security.checkPermission(SecurityConstants.WATCH_MOUSE_PERMISSION);

        }

        Point point = new Point(0, 0);

        int deviceNum = Toolkit.getDefaultToolkit().getMouseInfoPeer().fillPointWithCoords(point);

        GraphicsDevice[] gds = GraphicsEnvironment.getLocalGraphicsEnvironment().

                                   getScreenDevices();

        PointerInfo retval = null;

        if (areScreenDevicesIndependent(gds)) {

            retval = new PointerInfo(gds[deviceNum], point);

        } else {

            for (int i = 0; i < gds.length; i++) {

                GraphicsConfiguration gc = gds[i].getDefaultConfiguration();

                Rectangle bounds = gc.getBounds();

                if (bounds.contains(point)) {

                    retval = new PointerInfo(gds[i], point);

                }

            }

        }

        return retval;

    }

    private static boolean areScreenDevicesIndependent(GraphicsDevice[] gds) {

        for (int i = 0; i < gds.length; i++) {

            Rectangle bounds = gds[i].getDefaultConfiguration().getBounds();

            if (bounds.x != 0 || bounds.y != 0) {

                return false;

            }

        }

        return true;

    }

    /**

     * Returns the number of buttons on the mouse.

     * On systems without a mouse, returns <code>-1</code>.

     *

     * @exception HeadlessException if GraphicsEnvironment.isHeadless() returns true

     * @return number of buttons on the mouse

     * @since 1.5

     */

    public static int getNumberOfButtons() throws HeadlessException {

        if (GraphicsEnvironment.isHeadless()) {

            throw new HeadlessException();

        }

        Object prop = Toolkit.getDefaultToolkit().

                              getDesktopProperty("awt.mouse.numButtons");

        if (prop instanceof Integer) {

            return ((Integer)prop).intValue();

        }

        // This should never happen.

        assert false : "awt.mouse.numButtons is not an integer property";

        return 0;

    }

}