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

 *

 * 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.  Oracle designates this

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

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * 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.ItemSelectable;

/**

 * A semantic event which indicates that an item was selected or deselected.

 * This high-level event is generated by an ItemSelectable object (such as a

 * List) when an item is selected or deselected by the user.

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

 * registered to receive such events using the component's

 * <code>addItemListener</code> method.

 * <P>

 * The object that implements the <code>ItemListener</code> interface gets

 * this <code>ItemEvent</code> when the event occurs. The listener is

 * spared the details of processing individual mouse movements and mouse

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

 * "item selected" or "item deselected".

 * <p>

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

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

 * in the range from {@code ITEM_FIRST} to {@code ITEM_LAST}.

 * <p>

 * The {@code stateChange} of any {@code ItemEvent} instance takes one of the following

 * values:

 *                     <ul>

 *                     <li> {@code ItemEvent.SELECTED}

 *                     <li> {@code ItemEvent.DESELECTED}

 *                     </ul>

 * Assigning the value different from listed above will cause an unspecified behavior.

 *

 * @author Carl Quinn

 *

 * @see java.awt.ItemSelectable

 * @see ItemListener

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

 *

 * @since 1.1

 */

public class ItemEvent extends AWTEvent {

    /**

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

     */

    public static final int ITEM_FIRST          = 701;

    /**

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

     */

    public static final int ITEM_LAST           = 701;

    /**

     * This event id indicates that an item's state changed.

     */

    public static final int ITEM_STATE_CHANGED  = ITEM_FIRST; //Event.LIST_SELECT

    /**

     * This state-change value indicates that an item was selected.

     */

    public static final int SELECTED = 1;

    /**

     * This state-change-value indicates that a selected item was deselected.

     */

    public static final int DESELECTED  = 2;

    /**

     * The item whose selection state has changed.

     *

     * @serial

     * @see #getItem()

     */

    Object item;

    /**

     * <code>stateChange</code> indicates whether the <code>item</code>

     * was selected or deselected.

     *

     * @serial

     * @see #getStateChange()

     */

    int stateChange;

    /*

     * JDK 1.1 serialVersionUID

     */

    private static final long serialVersionUID = -608708132447206933L;

    /**

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

     * <p> This method throws an

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

     * is <code>null</code>.

     *

     * @param source The <code>ItemSelectable</code> object

     *               that originated the event

     * @param id           The integer that identifies the event type.

     *                     For information on allowable values, see

     *                     the class description for {@link ItemEvent}

     * @param item   An object -- the item affected by the event

     * @param stateChange  An integer that indicates whether the item was

     *               selected or deselected.

     *                     For information on allowable values, see

     *                     the class description for {@link ItemEvent}

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

     * @see #getItemSelectable()

     * @see #getID()

     * @see #getStateChange()

     */

    public ItemEvent(ItemSelectable source, int id, Object item, int stateChange) {

        super(source, id);

        this.item = item;

        this.stateChange = stateChange;

    }

    /**

     * Returns the originator of the event.

     *

     * @return the ItemSelectable object that originated the event.

     */

    public ItemSelectable getItemSelectable() {

        return (ItemSelectable)source;

    }

   /**

    * Returns the item affected by the event.

    *

    * @return the item (object) that was affected by the event

    */

    public Object getItem() {

        return item;

    }

   /**

    * Returns the type of state change (selected or deselected).

    *

    * @return an integer that indicates whether the item was selected

    *         or deselected

    *

    * @see #SELECTED

    * @see #DESELECTED

    */

    public int getStateChange() {

        return stateChange;

    }

    /**

     * Returns a parameter string identifying this item 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;

        switch(id) {

          case ITEM_STATE_CHANGED:

              typeStr = "ITEM_STATE_CHANGED";

              break;

          default:

              typeStr = "unknown type";

        }

        String stateStr;

        switch(stateChange) {

          case SELECTED:

              stateStr = "SELECTED";

              break;

          case DESELECTED:

              stateStr = "DESELECTED";

              break;

          default:

              stateStr = "unknown type";

        }

        return typeStr + ",item="+item + ",stateChange="+stateStr;

    }

}