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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * published by the Free Software Foundation.  Oracle designates this

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

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 * 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,

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 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package java.awt.event;

import java.awt.AWTEvent;

import java.awt.Event;

/**

 * A semantic event which indicates that a component-defined action occurred.

 * This high-level event is generated by a component (such as a

 * <code>Button</code>) when

 * the component-specific action occurs (such as being pressed).

 * The event is passed to every <code>ActionListener</code> object

 * that registered to receive such events using the component's

 * <code>addActionListener</code> method.

 * <p>

 * <b>Note:</b> To invoke an <code>ActionEvent</code> on a

 * <code>Button</code> using the keyboard, use the Space bar.

 * <P>

 * The object that implements the <code>ActionListener</code> interface

 * gets this <code>ActionEvent</code> when the event occurs. The listener

 * is therefore spared the details of processing individual mouse movements

 * and mouse clicks, and can instead process a "meaningful" (semantic)

 * event like "button pressed".

 * <p>

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

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

 * in the range from {@code ACTION_FIRST} to {@code ACTION_LAST}.

 *

 * @see ActionListener

 * @see <a href="http://java.sun.com/docs/books/tutorial/uiswing/events/actionlistener.html">Tutorial: How to Write an Action Listener</a>

 *

 * @author Carl Quinn

 * @since 1.1

 */

public class ActionEvent extends AWTEvent {

    /**

     * The shift modifier. An indicator that the shift key was held

     * down during the event.

     */

    public static final int SHIFT_MASK          = Event.SHIFT_MASK;

    /**

     * The control modifier. An indicator that the control key was held

     * down during the event.

     */

    public static final int CTRL_MASK           = Event.CTRL_MASK;

    /**

     * The meta modifier. An indicator that the meta key was held

     * down during the event.

     */

    public static final int META_MASK           = Event.META_MASK;

    /**

     * The alt modifier. An indicator that the alt key was held

     * down during the event.

     */

    public static final int ALT_MASK            = Event.ALT_MASK;

    /**

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

     */

    public static final int ACTION_FIRST                = 1001;

    /**

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

     */

    public static final int ACTION_LAST                 = 1001;

    /**

     * This event id indicates that a meaningful action occured.

     */

    public static final int ACTION_PERFORMED    = ACTION_FIRST; //Event.ACTION_EVENT

    /**

     * The nonlocalized string that gives more details

     * of what actually caused the event.

     * This information is very specific to the component

     * that fired it.

     * @serial

     * @see #getActionCommand

     */

    String actionCommand;

    /**

     * Timestamp of when this event occurred. Because an ActionEvent is a high-

     * level, semantic event, the timestamp is typically the same as an

     * underlying InputEvent.

     *

     * @serial

     * @see #getWhen

     */

    long when;

    /**

     * This represents the key modifier that was selected,

     * and is used to determine the state of the selected key.

     * If no modifier has been selected it will default to

     * zero.

     *

     * @serial

     * @see #getModifiers

     */

    int modifiers;

    /*

     * JDK 1.1 serialVersionUID

     */

    private static final long serialVersionUID = -7671078796273832149L;

    /**

     * Constructs an <code>ActionEvent</code> object.

     * <p>

     * This method throws an

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

     * is <code>null</code>.

     * A <code>null</code> <code>command</code> string is legal,

     * but not recommended.

     *

     * @param source  The object that originated the event

     * @param id      An integer that identifies the event.

     *                     For information on allowable values, see

     *                     the class description for {@link ActionEvent}

     * @param command A string that may specify a command (possibly one

     *                of several) associated with the event

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

     * @see #getSource()

     * @see #getID()

     * @see #getActionCommand()

     */

    public ActionEvent(Object source, int id, String command) {

        this(source, id, command, 0);

    }

    /**

     * Constructs an <code>ActionEvent</code> object with modifier keys.

     * <p>

     * This method throws an

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

     * is <code>null</code>.

     * A <code>null</code> <code>command</code> string is legal,

     * but not recommended.

     *

     * @param source  The object that originated the event

     * @param id      An integer that identifies the event.

     *                     For information on allowable values, see

     *                     the class description for {@link ActionEvent}

     * @param command A string that may specify a command (possibly one

     *                of several) associated with the event

     * @param modifiers The modifier keys down during event

     *                  (shift, ctrl, alt, meta).

     *                  Passing negative parameter is not recommended.

     *                  Zero value means that no modifiers were passed

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

     * @see #getSource()

     * @see #getID()

     * @see #getActionCommand()

     * @see #getModifiers()

     */

    public ActionEvent(Object source, int id, String command, int modifiers) {

        this(source, id, command, 0, modifiers);

    }

    /**

     * Constructs an <code>ActionEvent</code> object with the specified

     * modifier keys and timestamp.

     * <p>

     * This method throws an

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

     * is <code>null</code>.

     * A <code>null</code> <code>command</code> string is legal,

     * but not recommended.

     *

     * @param source    The object that originated the event

     * @param id      An integer that identifies the event.

     *                     For information on allowable values, see

     *                     the class description for {@link ActionEvent}

     * @param command A string that may specify a command (possibly one

     *                of several) associated with the event

     * @param modifiers The modifier keys down during event

     *                  (shift, ctrl, alt, meta).

     *                  Passing negative parameter is not recommended.

     *                  Zero value means that no modifiers were passed

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

     *               Passing negative or zero value

     *               is not recommended

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

     * @see #getSource()

     * @see #getID()

     * @see #getActionCommand()

     * @see #getModifiers()

     * @see #getWhen()

     *

     * @since 1.4

     */

    public ActionEvent(Object source, int id, String command, long when,

                       int modifiers) {

        super(source, id);

        this.actionCommand = command;

        this.when = when;

        this.modifiers = modifiers;

    }

    /**

     * Returns the command string associated with this action.

     * This string allows a "modal" component to specify one of several

     * commands, depending on its state. For example, a single button might

     * toggle between "show details" and "hide details". The source object

     * and the event would be the same in each case, but the command string

     * would identify the intended action.

     * <p>

     * Note that if a <code>null</code> command string was passed

     * to the constructor for this <code>ActionEvent</code>, this

     * this method returns <code>null</code>.

     *

     * @return the string identifying the command for this event

     */

    public String getActionCommand() {

        return actionCommand;

    }

    /**

     * Returns the timestamp of when this event occurred. Because an

     * ActionEvent is a high-level, semantic event, the timestamp is typically

     * the same as an underlying InputEvent.

     *

     * @return this event's timestamp

     * @since 1.4

     */

    public long getWhen() {

        return when;

    }

    /**

     * Returns the modifier keys held down during this action event.

     *

     * @return the bitwise-or of the modifier constants

     */

    public int getModifiers() {

        return modifiers;

    }

    /**

     * Returns a parameter string identifying this action event.

     * This method is useful for event-logging and for debugging.

     *

     * @return a string identifying the event and its associated command

     */

    public String paramString() {

        String typeStr;

        switch(id) {

          case ACTION_PERFORMED:

              typeStr = "ACTION_PERFORMED";

              break;

          default:

              typeStr = "unknown type";

        }

        return typeStr + ",cmd="+actionCommand+",when="+when+",modifiers="+

            KeyEvent.getKeyModifiersText(modifiers);

    }

}