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 * published by the Free Software Foundation.  Oracle designates this

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 * This code is distributed in the hope that it will be useful, but WITHOUT

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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).

 *

 * You should have received a copy of the GNU General Public License version

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package java.awt.event;

import java.awt.AWTEvent;

import java.awt.Component;

import java.awt.Rectangle;

/**

 * A low-level event which indicates that a component moved, changed

 * size, or changed visibility (also, the root class for the other

 * component-level events).

 * <P>

 * Component events are provided for notification purposes ONLY;

 * The AWT will automatically handle component moves and resizes

 * internally so that GUI layout works properly regardless of

 * whether a program is receiving these events or not.

 * <P>

 * In addition to serving as the base class for other component-related

 * events (InputEvent, FocusEvent, WindowEvent, ContainerEvent),

 * this class defines the events that indicate changes in

 * a component's size, position, or visibility.

 * <P>

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

 * List) when the component is moved, resized, rendered invisible, or made

 * visible again. The event is passed to every <code>ComponentListener</code>

 * or <code>ComponentAdapter</code> object which registered to receive such

 * events using the component's <code>addComponentListener</code> method.

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

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

 * gets this <code>ComponentEvent</code> when the event occurs.

 * <p>

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

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

 * in the range from {@code COMPONENT_FIRST} to {@code COMPONENT_LAST}.

 *

 * @see ComponentAdapter

 * @see ComponentListener

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

 *

 * @author Carl Quinn

 * @since 1.1

 */

public class ComponentEvent extends AWTEvent {

    /**

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

     */

    public static final int COMPONENT_FIRST             = 100;

    /**

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

     */

    public static final int COMPONENT_LAST              = 103;

   /**

     * This event indicates that the component's position changed.

     */

    /**

     * This event indicates that the component's size changed.

     */

    /**

     * This event indicates that the component was made visible.

     */

    /**

     * This event indicates that the component was rendered invisible.

     */

    /*

     * JDK 1.1 serialVersionUID

     */

    private static final long serialVersionUID = 8101406823902992965L;

    /**

     * Constructs a <code>ComponentEvent</code> object.

     * <p> 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 ComponentEvent}

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

     * @see #getComponent()

     * @see #getID()

     */

    public ComponentEvent(Component source, int id) {

        super(source, id);

    }

    /**

     * Returns the originator of the event.

     *

     * @return the <code>Component</code> object that originated

     * the event, or <code>null</code> if the object is not a

     * <code>Component</code>.

     */

    public Component getComponent() {

        return (source instanceof Component) ? (Component)source : null;

    }

    /**

     * Returns a parameter string identifying this event.

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

     *

     * @return a string identifying the event and its attributes

     */

    public String paramString() {

        String typeStr;

        Rectangle b = (source !=null

                       ? ((Component)source).getBounds()

                       : null);

        switch(id) {

          case COMPONENT_SHOWN:

              typeStr = "COMPONENT_SHOWN";

              break;

          case COMPONENT_HIDDEN:

              typeStr = "COMPONENT_HIDDEN";

              break;

          case COMPONENT_MOVED:

              typeStr = "COMPONENT_MOVED ("+

                         b.x+","+b.y+" "+b.width+"x"+b.height+")";

              break;

          case COMPONENT_RESIZED:

              typeStr = "COMPONENT_RESIZED ("+

                         b.x+","+b.y+" "+b.width+"x"+b.height+")";

              break;

          default:

              typeStr = "unknown type";

        }

        return typeStr;

    }

}