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 * 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

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 * 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).

 *

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package java.awt.event;

import java.awt.Component;

import java.awt.GraphicsEnvironment;

import java.awt.Point;

import java.awt.Toolkit;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.awt.IllegalComponentStateException;

/**

 * An event which indicates that a mouse action occurred in a component.

 * A mouse action is considered to occur in a particular component if and only

 * if the mouse cursor is over the unobscured part of the component's bounds

 * when the action happens.

 * For lightweight components, such as Swing's components, mouse events

 * are only dispatched to the component if the mouse event type has been

 * enabled on the component. A mouse event type is enabled by adding the

 * appropriate mouse-based {@code EventListener} to the component

 * ({@link MouseListener} or {@link MouseMotionListener}), or by invoking

 * {@link Component#enableEvents(long)} with the appropriate mask parameter

 * ({@code AWTEvent.MOUSE_EVENT_MASK} or {@code AWTEvent.MOUSE_MOTION_EVENT_MASK}).

 * If the mouse event type has not been enabled on the component, the

 * corresponding mouse events are dispatched to the first ancestor that

 * has enabled the mouse event type.

 *<p>

 * For example, if a {@code MouseListener} has been added to a component, or

 * {@code enableEvents(AWTEvent.MOUSE_EVENT_MASK)} has been invoked, then all

 * the events defined by {@code MouseListener} are dispatched to the component.

 * On the other hand, if a {@code MouseMotionListener} has not been added and

 * {@code enableEvents} has not been invoked with

 * {@code AWTEvent.MOUSE_MOTION_EVENT_MASK}, then mouse motion events are not

 * dispatched to the component. Instead the mouse motion events are

 * dispatched to the first ancestors that has enabled mouse motion

 * events.

 * <P>

 * This low-level event is generated by a component object for:

 * <ul>

 * <li>Mouse Events

 *     <ul>

 *     <li>a mouse button is pressed

 *     <li>a mouse button is released

 *     <li>a mouse button is clicked (pressed and released)

 *     <li>the mouse cursor enters the unobscured part of component's geometry

 *     <li>the mouse cursor exits the unobscured part of component's geometry

 *     </ul>

 * <li> Mouse Motion Events

 *     <ul>

 *     <li>the mouse is moved

 *     <li>the mouse is dragged

 *     </ul>

 * </ul>

 * <P>

 * A <code>MouseEvent</code> object is passed to every

 * <code>MouseListener</code>

 * or <code>MouseAdapter</code> object which is registered to receive

 * the "interesting" mouse events using the component's

 * <code>addMouseListener</code> method.

 * (<code>MouseAdapter</code> objects implement the

 * <code>MouseListener</code> interface.) Each such listener object

 * gets a <code>MouseEvent</code> containing the mouse event.

 * <P>

 * A <code>MouseEvent</code> object is also passed to every

 * <code>MouseMotionListener</code> or

 * <code>MouseMotionAdapter</code> object which is registered to receive

 * mouse motion events using the component's

 * <code>addMouseMotionListener</code>

 * method. (<code>MouseMotionAdapter</code> objects implement the

 * <code>MouseMotionListener</code> interface.) Each such listener object

 * gets a <code>MouseEvent</code> containing the mouse motion event.

 * <P>

 * When a mouse button is clicked, events are generated and sent to the

 * registered <code>MouseListener</code>s.

 * The state of modal keys can be retrieved using {@link InputEvent#getModifiers}

 * and {@link InputEvent#getModifiersEx}.

 * The button mask returned by {@link InputEvent#getModifiers} reflects

 * only the button that changed state, not the current state of all buttons.

 * (Note: Due to overlap in the values of ALT_MASK/BUTTON2_MASK and

 * META_MASK/BUTTON3_MASK, this is not always true for mouse events involving

 * modifier keys).

 * To get the state of all buttons and modifier keys, use

 * {@link InputEvent#getModifiersEx}.

 * The button which has changed state is returned by {@link MouseEvent#getButton}

 * <P>

 * For example, if the first mouse button is pressed, events are sent in the

 * following order:

 * <PRE>

 *    <b   >id           </b   >   <b   >modifiers   </b   > <b   >button </b   >

 *    <code>MOUSE_PRESSED</code>:  <code>BUTTON1_MASK</code> <code>BUTTON1</code>

 *    <code>MOUSE_RELEASED</code>: <code>BUTTON1_MASK</code> <code>BUTTON1</code>

 *    <code>MOUSE_CLICKED</code>:  <code>BUTTON1_MASK</code> <code>BUTTON1</code>

 * </PRE>

 * When multiple mouse buttons are pressed, each press, release, and click

 * results in a separate event.

 * <P>

 * For example, if the user presses <b>button 1</b> followed by

 * <b>button 2</b>, and then releases them in the same order,

 * the following sequence of events is generated:

 * <PRE>

 *    <b   >id           </b   >   <b   >modifiers   </b   > <b   >button </b   >

 *    <code>MOUSE_PRESSED</code>:  <code>BUTTON1_MASK</code> <code>BUTTON1</code>

 *    <code>MOUSE_PRESSED</code>:  <code>BUTTON2_MASK</code> <code>BUTTON2</code>

 *    <code>MOUSE_RELEASED</code>: <code>BUTTON1_MASK</code> <code>BUTTON1</code>

 *    <code>MOUSE_CLICKED</code>:  <code>BUTTON1_MASK</code> <code>BUTTON1</code>

 *    <code>MOUSE_RELEASED</code>: <code>BUTTON2_MASK</code> <code>BUTTON2</code>

 *    <code>MOUSE_CLICKED</code>:  <code>BUTTON2_MASK</code> <code>BUTTON2</code>

 * </PRE>

 * If <b>button 2</b> is released first, the

 * <code>MOUSE_RELEASED</code>/<code>MOUSE_CLICKED</code> pair

 * for <code>BUTTON2_MASK</code> arrives first,

 * followed by the pair for <code>BUTTON1_MASK</code>.

 * <p>

 *

 * <code>MOUSE_DRAGGED</code> events are delivered to the <code>Component</code>

 * in which the mouse button was pressed until the mouse button is released

 * (regardless of whether the mouse position is within the bounds of the

 * <code>Component</code>).  Due to platform-dependent Drag&Drop implementations,

 * <code>MOUSE_DRAGGED</code> events may not be delivered during a native

 * Drag&Drop operation.

 *

 * In a multi-screen environment mouse drag events are delivered to the

 * <code>Component</code> even if the mouse position is outside the bounds of the

 * <code>GraphicsConfiguration</code> associated with that

 * <code>Component</code>. However, the reported position for mouse drag events

 * in this case may differ from the actual mouse position:

 * <ul>

 * <li>In a multi-screen environment without a virtual device:

 * <br>

 * The reported coordinates for mouse drag events are clipped to fit within the

 * bounds of the <code>GraphicsConfiguration</code> associated with

 * the <code>Component</code>.

 * <li>In a multi-screen environment with a virtual device:

 * <br>

 * The reported coordinates for mouse drag events are clipped to fit within the

 * bounds of the virtual device associated with the <code>Component</code>.

 * </ul>

 * <p>

 * An unspecified behavior will be caused if the {@code id} parameter

 * of any particular {@code MouseEvent} instance is not

 * in the range from {@code MOUSE_FIRST} to {@code MOUSE_LAST}-1

 * ({@code MOUSE_WHEEL} is not acceptable).

 *

 * @author Carl Quinn

 *

 * @see MouseAdapter

 * @see MouseListener

 * @see MouseMotionAdapter

 * @see MouseMotionListener

 * @see MouseWheelListener

 * @see <a href="http://java.sun.com/docs/books/tutorial/post1.0/ui/mouselistener.html">Tutorial: Writing a Mouse Listener</a>

 * @see <a href="http://java.sun.com/docs/books/tutorial/post1.0/ui/mousemotionlistener.html">Tutorial: Writing a Mouse Motion Listener</a>

 *

 * @since 1.1

 */

public class MouseEvent extends InputEvent {

    /**

     * The first number in the range of ids used for mouse events.

     */

    public static final int MOUSE_FIRST         = 500;

    /**

     * The last number in the range of ids used for mouse events.

     */

    public static final int MOUSE_LAST          = 507;

    /**

     * The "mouse clicked" event. This <code>MouseEvent</code>

     * occurs when a mouse button is pressed and released.

     */

    public static final int MOUSE_CLICKED = MOUSE_FIRST;

    /**

     * The "mouse pressed" event. This <code>MouseEvent</code>

     * occurs when a mouse button is pushed down.

     */

    public static final int MOUSE_PRESSED = 1 + MOUSE_FIRST; //Event.MOUSE_DOWN

    /**

     * The "mouse released" event. This <code>MouseEvent</code>

     * occurs when a mouse button is let up.

     */

    public static final int MOUSE_RELEASED = 2 + MOUSE_FIRST; //Event.MOUSE_UP

    /**

     * The "mouse moved" event. This <code>MouseEvent</code>

     * occurs when the mouse position changes.

     */

    public static final int MOUSE_MOVED = 3 + MOUSE_FIRST; //Event.MOUSE_MOVE

    /**

     * The "mouse entered" event. This <code>MouseEvent</code>

     * occurs when the mouse cursor enters the unobscured part of component's

     * geometry.

     */

    public static final int MOUSE_ENTERED = 4 + MOUSE_FIRST; //Event.MOUSE_ENTER

    /**

     * The "mouse exited" event. This <code>MouseEvent</code>

     * occurs when the mouse cursor exits the unobscured part of component's

     * geometry.

     */

    public static final int MOUSE_EXITED = 5 + MOUSE_FIRST; //Event.MOUSE_EXIT

    /**

     * The "mouse dragged" event. This <code>MouseEvent</code>

     * occurs when the mouse position changes while a mouse button is pressed.

     */

    public static final int MOUSE_DRAGGED = 6 + MOUSE_FIRST; //Event.MOUSE_DRAG

    /**

     * The "mouse wheel" event.  This is the only <code>MouseWheelEvent</code>.

     * It occurs when a mouse equipped with a wheel has its wheel rotated.

     * @since 1.4

     */

    public static final int MOUSE_WHEEL = 7 + MOUSE_FIRST;

    /**

     * Indicates no mouse buttons; used by {@link #getButton}.

     * @since 1.4

     */

    public static final int NOBUTTON = 0;

    /**

     * Indicates mouse button #1; used by {@link #getButton}.

     * @since 1.4

     */

    public static final int BUTTON1 = 1;

    /**

     * Indicates mouse button #2; used by {@link #getButton}.

     * @since 1.4

     */

    public static final int BUTTON2 = 2;

    /**

     * Indicates mouse button #3; used by {@link #getButton}.

     * @since 1.4

     */

    public static final int BUTTON3 = 3;

    /**

     * The mouse event's x coordinate.

     * The x value is relative to the component that fired the event.

     *

     * @serial

     * @see #getX()

     */

    int x;

    /**

     * The mouse event's y coordinate.

     * The y value is relative to the component that fired the event.

     *

     * @serial

     * @see #getY()

     */

    int y;

    /**

     * The mouse event's x absolute coordinate.

     * In a virtual device multi-screen environment in which the

     * desktop area could span multiple physical screen devices,

     * this coordinate is relative to the virtual coordinate system.

     * Otherwise, this coordinate is relative to the coordinate system

     * associated with the Component's GraphicsConfiguration.

     *

     * @serial

   */

    private int xAbs;

    /**

     * The mouse event's y absolute coordinate.

     * In a virtual device multi-screen environment in which the

     * desktop area could span multiple physical screen devices,

     * this coordinate is relative to the virtual coordinate system.

     * Otherwise, this coordinate is relative to the coordinate system

     * associated with the Component's GraphicsConfiguration.

     *

     * @serial

     */

    private int yAbs;

    /**

     * Indicates the number of quick consecutive clicks of

     * a mouse button.

     * clickCount will be valid for only three mouse events :<BR>

     * <code>MOUSE_CLICKED</code>,

     * <code>MOUSE_PRESSED</code> and

     * <code>MOUSE_RELEASED</code>.

     * For the above, the <code>clickCount</code> will be at least 1.

     * For all other events the count will be 0.

     *

     * @serial

     * @see #getClickCount().

     */

    int clickCount;

    /**

     * Indicates which, if any, of the mouse buttons has changed state.

     *

     * The only legal values are the following constants:

     * <code>NOBUTTON</code>,

     * <code>BUTTON1</code>,

     * <code>BUTTON2</code> or

     * <code>BUTTON3</code>.

     * @serial

     * @see #getButton().

     */

    int button;

    /**

     * A property used to indicate whether a Popup Menu

     * should appear  with a certain gestures.

     * If <code>popupTrigger</code> = <code>false</code>,

     * no popup menu should appear.  If it is <code>true</code>

     * then a popup menu should appear.

     *

     * @serial

     * @see java.awt.PopupMenu

     * @see #isPopupTrigger()

     */

    boolean popupTrigger = false;

    /*

     * JDK 1.1 serialVersionUID

     */

    private static final long serialVersionUID = -991214153494842848L;

    static {

        /* ensure that the necessary native libraries are loaded */

        NativeLibLoader.loadLibraries();

        if (!GraphicsEnvironment.isHeadless()) {

            initIDs();

        }

    }

    /**

     * Initialize JNI field and method IDs for fields that may be

       accessed from C.

     */

    private static native void initIDs();

    /**

     * Returns the absolute x, y position of the event.

     * In a virtual device multi-screen environment in which the

     * desktop area could span multiple physical screen devices,

     * these coordinates are relative to the virtual coordinate system.

     * Otherwise, these coordinates are relative to the coordinate system

     * associated with the Component's GraphicsConfiguration.

     *

     * @return a <code>Point</code> object containing the absolute  x

     *  and y coordinates.

     *

     * @see java.awt.GraphicsConfiguration

     * @since 1.6

     */

    public Point getLocationOnScreen(){

      return new Point(xAbs, yAbs);

    }

    /**

     * Returns the absolute horizontal x position of the event.

     * In a virtual device multi-screen environment in which the

     * desktop area could span multiple physical screen devices,

     * this coordinate is relative to the virtual coordinate system.

     * Otherwise, this coordinate is relative to the coordinate system

     * associated with the Component's GraphicsConfiguration.

     *

     * @return x  an integer indicating absolute horizontal position.

     *

     * @see java.awt.GraphicsConfiguration

     * @since 1.6

     */

    public int getXOnScreen() {

        return xAbs;

    }

    /**

     * Returns the absolute vertical y position of the event.

     * In a virtual device multi-screen environment in which the

     * desktop area could span multiple physical screen devices,

     * this coordinate is relative to the virtual coordinate system.

     * Otherwise, this coordinate is relative to the coordinate system

     * associated with the Component's GraphicsConfiguration.

     *

     * @return y  an integer indicating absolute vertical position.

     *

     * @see java.awt.GraphicsConfiguration

     * @since 1.6

     */

    public int getYOnScreen() {

        return yAbs;

    }

    /**

     * Constructs a <code>MouseEvent</code> object with the

     * specified source component,

     * type, modifiers, coordinates, and click count.

     * <p>

     * Creating an invalid event (such

     * as by using more than one of the old _MASKs, or modifier/button

     * values which don't match) results in unspecified behavior.

     * An invocation of the form

     * <tt>MouseEvent(source, id, when, modifiers, x, y, clickCount, popupTrigger, button)</tt>

     * behaves in exactly the same way as the invocation

     * <tt> {@link #MouseEvent(Component, int, long, int, int, int,

     * int, int, int, boolean, int) MouseEvent}(source, id, when, modifiers,

     * x, y, xAbs, yAbs, clickCount, popupTrigger, button)</tt>

     * where xAbs and yAbs defines as source's location on screen plus

     * relative coordinates x and y.

     * xAbs and yAbs are set to zero if the source is not showing.

     * This method throws an

     * <code>IllegalArgumentException</code> if <code>source</code>

     * is <code>null</code>.

     *

     * @param source       The <code>Component</code> that originated the event

     * @param id              An integer indicating the type of event.

     *                     For information on allowable values, see

     *                     the class description for {@link MouseEvent}

     * @param when         A long integer that gives the time the event occurred.

     *                     Passing negative or zero value

     *                     is not recommended

     * @param modifiers    The modifier keys down during event (e.g. shift, ctrl,

     *                     alt, meta)

     *                     Passing negative parameter

     *                     is not recommended.

     *                     Zero value means that no modifiers were passed.

     *                     Use either an extended _DOWN_MASK or old _MASK modifiers,

     *                     however do not mix models in the one event.

     *                     The extended modifiers are preferred for using

     * @param x            The horizontal x coordinate for the mouse location.

     *                       It is allowed to pass negative values

     * @param y            The vertical y coordinate for the mouse location.

     *                       It is allowed to pass negative values

     * @param clickCount   The number of mouse clicks associated with event.

     *                       Passing negative value

     *                       is not recommended

     * @param popupTrigger A boolean that equals {@code true} if this event

     *                     is a trigger for a popup menu

     * @param button       An integer that indicates, which of the mouse buttons has

     *                     changed its state

     * @throws IllegalArgumentException if an invalid <code>button</code>

     *            value is passed in

     * @throws IllegalArgumentException if <code>source</code> is null

     * @see #getSource()

     * @see #getID()

     * @see #getWhen()

     * @see #getModifiers()

     * @see #getX()

     * @see #getY()

     * @see #getClickCount()

     * @see #isPopupTrigger()

     * @see #getButton()

     * @since 1.4

     */

    public MouseEvent(Component source, int id, long when, int modifiers,

                      int x, int y, int clickCount, boolean popupTrigger,

                      int button)

    {

        this(source, id, when, modifiers, x, y, 0, 0, clickCount, popupTrigger, button);

        Point eventLocationOnScreen = new Point(0, 0);

        try {

          eventLocationOnScreen = source.getLocationOnScreen();

          this.xAbs = eventLocationOnScreen.x + x;

          this.yAbs = eventLocationOnScreen.y + y;

        } catch (IllegalComponentStateException e){

          this.xAbs = 0;

          this.yAbs = 0;

        }

    }

    /**

     * Constructs a <code>MouseEvent</code> object with the

     * specified source component,

     * type, modifiers, coordinates, and click count.

     * An invocation of the form

     * <tt>MouseEvent(source, id, when, modifiers, x, y, clickCount, popupTrigger)</tt>

     * behaves in exactly the same way as the invocation

     * <tt> {@link #MouseEvent(Component, int, long, int, int, int,

     * int, int, int, boolean, int) MouseEvent}(source, id, when, modifiers,

     * x, y, xAbs, yAbs, clickCount, popupTrigger, MouseEvent.NOBUTTON)</tt>

     * where xAbs and yAbs defines as source's location on screen plus

     * relative coordinates x and y.

     * xAbs and yAbs are set to zero if the source is not showing.

     * This method throws an <code>IllegalArgumentException</code>

     * if <code>source</code> is <code>null</code>.

     *

     * @param source       The <code>Component</code> that originated the event

     * @param id              An integer indicating the type of event.

     *                     For information on allowable values, see

     *                     the class description for {@link MouseEvent}

     * @param when         A long integer that gives the time the event occurred.

     *                     Passing negative or zero value

     *                     is not recommended

     * @param modifiers    The modifier keys down during event (e.g. shift, ctrl,

     *                     alt, meta)

     *                     Passing negative parameter

     *                     is not recommended.