/*
 * Copyright (c) 2003, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

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.AWT.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;
 }

}