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package java.awt;

import sun.awt.AWTPermissions;
import sun.awt.ComponentFactory;


MouseInfo 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
/**
 * {@code MouseInfo}  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 constructor to prevent instantiation.
     */
    private MouseInfo() {
    }

    
Returns a PointerInfo instance that represents the current location of the mouse pointer. The GraphicsDevice stored in this PointerInfo contains the mouse pointer. The coordinate system used for the mouse position depends on whether or not the GraphicsDevice 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 GraphicsDevice. See GraphicsConfiguration for more information about the virtual screen devices. On systems without a mouse, returns null. 
 If there is a security manager, its checkPermission method is called with an AWTPermission("watchMousePointer") permission before creating and returning a PointerInfo object. This may result in a SecurityException. 
Throws:
  • HeadlessException – if GraphicsEnvironment.isHeadless() returns true
  • SecurityException – if a security manager exists and its checkPermission method doesn't allow the operation
See Also:
Returns:   location of the mouse pointer
Since:    1.5
/**
     * Returns a {@code PointerInfo} instance that represents the current
     * location of the mouse pointer.
     * The {@code GraphicsDevice} stored in this {@code PointerInfo}
     * contains the mouse pointer. The coordinate system used for the mouse position
     * depends on whether or not the {@code GraphicsDevice} 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}. See {@link GraphicsConfiguration}
     * for more information about the virtual screen devices.
     * On systems without a mouse, returns {@code null}.
     * <p>
     * If there is a security manager, its {@code checkPermission} method
     * is called with an {@code AWTPermission("watchMousePointer")}
     * permission before creating and returning a {@code PointerInfo}
     * object. This may result in a {@code SecurityException}.
     *
     * @exception HeadlessException if GraphicsEnvironment.isHeadless() returns true
     * @exception SecurityException if a security manager exists and its
     *            {@code checkPermission} 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(AWTPermissions.WATCH_MOUSE_PERMISSION);
        }

        Toolkit toolkit = Toolkit.getDefaultToolkit();
        Point point = new Point(0, 0);
        int deviceNum = 0;
        if (toolkit instanceof ComponentFactory) {
            deviceNum = ((ComponentFactory) toolkit).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 -1. The number of buttons is obtained from the AWT Toolkit by requesting the "awt.mouse.numButtons" desktop property which is set by the underlying native platform. 
Throws:
See Also:
Returns:number of buttons on the mouse
Since:1.5
/**
     * Returns the number of buttons on the mouse.
     * On systems without a mouse, returns {@code -1}.
     * The number of buttons is obtained from the AWT Toolkit
     * by requesting the {@code "awt.mouse.numButtons"} desktop property
     * which is set by the underlying native platform.
     *
     * @exception HeadlessException if GraphicsEnvironment.isHeadless() returns true
     * @return number of buttons on the mouse
     * @see Toolkit#getDesktopProperty
     * @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;
    }

}