/* Choice.java -- Java choice button widget.   Copyright (C) 1999, 2000, 2001, 2002 Free Software Foundation, Inc.This file is part of GNU Classpath.GNU Classpath is free software; you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe Free Software Foundation; either version 2, or (at your option)any later version.GNU Classpath is distributed in the hope that it will be useful, butWITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNUGeneral Public License for more details.You should have received a copy of the GNU General Public Licensealong with GNU Classpath; see the file COPYING.  If not, write to theFree Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA02111-1307 USA.Linking this library statically or dynamically with other modules ismaking a combined work based on this library.  Thus, the terms andconditions of the GNU General Public License cover the wholecombination.As a special exception, the copyright holders of this library give youpermission to link this library with independent modules to produce anexecutable, regardless of the license terms of these independentmodules, and to copy and distribute the resulting executable underterms of your choice, provided that you also meet, for each linkedindependent module, the terms and conditions of the license of thatmodule.  An independent module is a module which is not derived fromor based on this library.  If you modify this library, you may extendthis exception to your version of the library, but you are notobligated to do so.  If you do not wish to do so, delete thisexception statement from your version. */package java.awt;import java.awt.peer.ChoicePeer;import java.awt.peer.ComponentPeer;import java.awt.event.ItemEvent;import java.awt.event.ItemListener;import java.io.Serializable;import java.util.Vector;/**  * This class implements a drop down choice list.  *  * @author Aaron M. Renn (arenn@urbanophile.com)  */public class Choice extends Component implements ItemSelectable, Serializable{/* * Static Variables */// Serialization constantprivate static final long serialVersionUID = -4075310674757313071L;/*************************************************************************//* * Instance Variables *//**  * @serial A list of items for the choice box, which can be <code>null</code>.  */private Vector pItems = new Vector();/**  * @serial The index of the selected item in the choice box.  */private int selectedIndex = -1;// Listener chainprivate ItemListener item_listeners;/*************************************************************************//* * Constructors */  /**   * Initializes a new instance of <code>Choice</code>.   *   * @exception HeadlessException If GraphicsEnvironment.isHeadless()   * returns true   */  public Choice()  {    if (GraphicsEnvironment.isHeadless())      throw new HeadlessException ();  }/*************************************************************************//* * Instance Methods *//**  * Returns the number of items in the list.  *  * @return The number of items in the list.  */public intgetItemCount(){  return(pItems.size());}/*************************************************************************//**  * Returns the number of items in the list.  *  * @return The number of items in the list.  *  * @deprecated This method is deprecated in favor of <code>getItemCount</code>.  */public intcountItems(){  return(pItems.size());}/*************************************************************************//**  * Returns the item at the specified index in the list.  *  * @param index The index into the list to return the item from.  *  * @exception ArrayIndexOutOfBoundsException If the index is invalid.  */public StringgetItem(int index){  return((String)pItems.elementAt(index));}/*************************************************************************//**  * Adds the specified item to this choice box.  *  * @param item The item to add.  *  * @exception NullPointerException If the item's value is null  *  * @since 1.1  */public synchronized voidadd(String item){  if (item == null)    throw new NullPointerException ("item must be non-null");  pItems.addElement(item);  int i = pItems.size () - 1;  if (peer != null)    {      ChoicePeer cp = (ChoicePeer) peer;      cp.add (item, i);    }  if (i == 0)    select (0);}/*************************************************************************//**  * Adds the specified item to this choice box.  *  * This method is oboslete since Java 2 platform 1.1. Please use @see add  * instead.  *  * @param item The item to add.  *  * @exception NullPointerException If the item's value is equal to null  */public synchronized voidaddItem(String item){  add(item);}/*************************************************************************//** Inserts an item into this Choice.  Existing items are shifted * upwards.  If the new item is the only item, then it is selected. * If the currently selected item is shifted, then the first item is * selected.  If the currently selected item is not shifted, then it * remains selected. * * @param item The item to add. * @param index The index at which the item should be inserted. * * @exception IllegalArgumentException If index is less than 0 */public synchronized voidinsert(String item, int index){  if (index < 0)    throw new IllegalArgumentException ("index may not be less then 0");  if (index > getItemCount ())    index = getItemCount ();  pItems.insertElementAt(item, index);  if (peer != null)    {      ChoicePeer cp = (ChoicePeer) peer;      cp.add (item, index);    }  if (getItemCount () == 1 || selectedIndex >= index)    select (0);}/*************************************************************************//**  * Removes the specified item from the choice box.  *  * @param item The item to remove.  *  * @exception IllegalArgumentException If the specified item doesn't exist.  */public synchronized voidremove(String item){  int index = pItems.indexOf(item);  if (index == -1)    throw new IllegalArgumentException ("item \""					+ item + "\" not found in Choice");  remove(index);}/*************************************************************************//**  * Removes the item at the specified index from the choice box.  *  * @param index The index of the item to remove.  *  * @exception IndexOutOfBoundsException If the index is not valid.  */public synchronized voidremove(int index){  pItems.removeElementAt(index);  if (peer != null)    {      ChoicePeer cp = (ChoicePeer) peer;      cp.remove (index);    }  if (index == selectedIndex)    select (0);  else if (selectedIndex > index)    --selectedIndex;}/*************************************************************************//**  * Removes all of the objects from this choice box.  */public synchronized voidremoveAll(){  int count = getItemCount();  for (int i = 0; i < count; i++)    {      // Always remove 0.      remove(0);    }}/*************************************************************************//**  * Returns the currently selected item, or null if no item is  * selected.  *  * @return The currently selected item.  */public synchronized StringgetSelectedItem(){  return (selectedIndex == -1	  ? null	  : ((String)pItems.elementAt(selectedIndex)));}/*************************************************************************//**  * Returns an array with one row containing the selected item.  *  * @return An array containing the selected item.  */public synchronized Object[]getSelectedObjects(){  if (selectedIndex == -1)    return null;  Object[] objs = new Object[1];  objs[0] = pItems.elementAt(selectedIndex);  return(objs);}/*************************************************************************//**  * Returns the index of the selected item.  *  * @return The index of the selected item.  */public intgetSelectedIndex(){  return(selectedIndex);}/*************************************************************************//**  * Forces the item at the specified index to be selected.  *  * @param index The index of the row to make selected.  *  * @exception IllegalArgumentException If the specified index is invalid.  */public synchronized voidselect(int index){  if ((index < 0) || (index > getItemCount()))    throw new IllegalArgumentException("Bad index: " + index);  this.selectedIndex = index;  if (peer != null)    {      ChoicePeer cp = (ChoicePeer) peer;      cp.select (index);    }}/*************************************************************************//**  * Forces the named item to be selected.  *  * @param item The item to be selected.  *  * @exception IllegalArgumentException If the specified item does not exist.  */public synchronized voidselect(String item){  int index = pItems.indexOf(item);  if (index >= 0)    select(index);}/*************************************************************************//**  * Creates the native peer for this object.  */public voidaddNotify(){  if (peer == null)    peer = getToolkit ().createChoice (this);  super.addNotify ();}/*************************************************************************//**  * Adds the specified listener to the list of registered listeners for  * this object.  *  * @param listener The listener to add.  */public synchronized voidaddItemListener(ItemListener listener){  item_listeners = AWTEventMulticaster.add(item_listeners, listener);}/*************************************************************************//**  * Removes the specified listener from the list of registered listeners for  * this object.  *  * @param listener The listener to remove.  */public synchronized voidremoveItemListener(ItemListener listener){  item_listeners = AWTEventMulticaster.remove(item_listeners, listener);}/*************************************************************************//**  * Processes this event by invoking <code>processItemEvent()</code> if the  * event is an instance of <code>ItemEvent</code>, otherwise the event  * is passed to the superclass.  *  * @param event The event to process.  */protected voidprocessEvent(AWTEvent event){  if (event instanceof ItemEvent)    processItemEvent((ItemEvent)event);  else    super.processEvent(event);}/*************************************************************************//**  * Processes item event by dispatching to any registered listeners.  *  * @param event The event to process.  */protected voidprocessItemEvent(ItemEvent event){  if (item_listeners != null)    item_listeners.itemStateChanged(event);}voiddispatchEventImpl(AWTEvent e){  if (e.id <= ItemEvent.ITEM_LAST      && e.id >= ItemEvent.ITEM_FIRST      && (item_listeners != null 	  || (eventMask & AWTEvent.ITEM_EVENT_MASK) != 0))    processEvent(e);  else    super.dispatchEventImpl(e);}/*************************************************************************//**  * Returns a debugging string for this object.  *  * @return A debugging string for this object.  */protected StringparamString(){  return ("selectedIndex=" + selectedIndex + "," + super.paramString());}} // class Choice