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/* JComboBox.java --
   Copyright (C) 2002, 2004, 2005, 2006,  Free Software Foundation, Inc.
 
This file is part of GNU Classpath.
 
GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.
 
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02110-1301 USA.
 
Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
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permission to link this library with independent modules to produce an
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package javax.swing;
 
import gnu.java.lang.CPStringBuilder;
 
import java.awt.ItemSelectable;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.KeyEvent;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.Vector;
 
import javax.accessibility.Accessible;
import javax.accessibility.AccessibleAction;
import javax.accessibility.AccessibleContext;
import javax.accessibility.AccessibleRole;
import javax.accessibility.AccessibleSelection;
import javax.swing.event.ListDataEvent;
import javax.swing.event.ListDataListener;
import javax.swing.event.PopupMenuEvent;
import javax.swing.event.PopupMenuListener;
import javax.swing.plaf.ComboBoxUI;
import javax.swing.plaf.ComponentUI;
import javax.swing.plaf.basic.ComboPopup;
 
/**
 * A component that allows a user to select any item in its list and
 * displays the selected item to the user. JComboBox also can show/hide a
 * popup menu containing its list of item whenever the mouse is pressed
 * over it.
 *
 * @author Andrew Selkirk
 * @author Olga Rodimina
 * @author Robert Schuster
 */
public class JComboBox extends JComponent implements ItemSelectable,
                                                     ListDataListener,
                                                     ActionListener,
                                                     Accessible
{
 
  private static final long serialVersionUID = 5654585963292734470L;
 
  /**
   * Classes implementing this interface are
   * responsible for matching key characters typed by the user with combo
   * box's items.
   */
  public static interface KeySelectionManager
  {
    int selectionForKey(char aKey, ComboBoxModel aModel);
  }
 
  /**
   * Maximum number of rows that should be visible by default  in the
   * JComboBox's popup
   */
  private static final int DEFAULT_MAXIMUM_ROW_COUNT = 8;
 
  /**
   * Data model used by JComboBox to keep track of its list data and currently
   * selected element in the list.
   */
  protected ComboBoxModel dataModel;
 
  /**
   * Renderer renders(paints) every object in the combo box list in its
   * associated list cell. This ListCellRenderer is used only when  this
   * JComboBox is uneditable.
   */
  protected ListCellRenderer renderer;
 
  /**
   * Editor that is responsible for editing an object in a combo box list.
   */
  protected ComboBoxEditor editor;
 
  /**
   * Number of rows that will be visible in the JComboBox's popup.
   */
  protected int maximumRowCount;
 
  /**
   * This field indicates if textfield of this JComboBox is editable or not.
   */
  protected boolean isEditable;
 
  /**
   * This field is reference to the current selection of the combo box.
   */
  protected Object selectedItemReminder;
 
  /**
   * keySelectionManager
   */
  protected KeySelectionManager keySelectionManager;
 
  /**
   * This actionCommand is used in ActionEvent that is fired to JComboBox's
   * ActionListeneres.
   */
  protected String actionCommand;
 
  /**
   * This property indicates if heavyweight popup or lightweight popup will be
   * used to diplay JComboBox's elements.
   */
  protected boolean lightWeightPopupEnabled;
 
  /**
   * The action taken when new item is selected in the JComboBox
   */
  private Action action;
 
  /**
   * since 1.4  If this field is set then comboBox's display area for the
   * selected item  will be set by default to this value.
   */
  private Object prototypeDisplayValue;
 
  /**
   * Constructs JComboBox object with specified data model for it.
   * <p>Note that the JComboBox will not change the value that
   * is preselected by your ComboBoxModel implementation.</p>
   *
   * @param model Data model that will be used by this JComboBox to keep track
   *        of its list of items.
   */
  public JComboBox(ComboBoxModel model)
  {
    setEditable(false);
    setEnabled(true);
    setMaximumRowCount(DEFAULT_MAXIMUM_ROW_COUNT);
    setModel(model);
    setActionCommand("comboBoxChanged");
 
    lightWeightPopupEnabled = true;
    isEditable = false;
 
    updateUI();
  }
 
  /**
   * Constructs JComboBox with specified list of items.
   *
   * @param itemArray array containing list of items for this JComboBox
   */
  public JComboBox(Object[] itemArray)
  {
    this(new DefaultComboBoxModel(itemArray));
 
    if (itemArray.length > 0)
      setSelectedIndex(0);
  }
 
  /**
   * Constructs JComboBox object with specified list of items.
   *
   * @param itemVector vector containing list of items for this JComboBox.
   */
  public JComboBox(Vector<?> itemVector)
  {
    this(new DefaultComboBoxModel(itemVector));
 
    if (itemVector.size() > 0)
      setSelectedIndex(0);
  }
 
  /**
   * Constructor. Creates new empty JComboBox. ComboBox's data model is set to
   * DefaultComboBoxModel.
   */
  public JComboBox()
  {
    this(new DefaultComboBoxModel());
  }
 
  /**
   * This method returns true JComboBox is editable and false otherwise
   *
   * @return boolean true if JComboBox is editable and false otherwise
   */
  public boolean isEditable()
  {
    return isEditable;
  }
 
  /*
   * This method adds ancestor listener to this JComboBox.
   */
  protected void installAncestorListener()
  {
    /* FIXME: Need to implement.
     *
     * Need to add ancestor listener to this JComboBox. This listener
     * should close combo box's popup list of items whenever it
     * receives an AncestorEvent.
     */
  }
 
  /**
   * Set the "UI" property of the combo box, which is a look and feel class
   * responsible for handling comboBox's input events and painting it.
   *
   * @param ui The new "UI" property
   */
  public void setUI(ComboBoxUI ui)
  {
    super.setUI(ui);
  }
 
  /**
   * This method sets this comboBox's UI to the UIManager's default for the
   * current look and feel.
   */
  public void updateUI()
  {
    setUI((ComboBoxUI) UIManager.getUI(this));
  }
 
  /**
   * This method returns the String identifier for the UI class to the used
   * with the JComboBox.
   *
   * @return The String identifier for the UI class.
   */
  public String getUIClassID()
  {
    return "ComboBoxUI";
  }
 
  /**
   * This method returns the UI used to display the JComboBox.
   *
   * @return The UI used to display the JComboBox.
   */
  public ComboBoxUI getUI()
  {
    return (ComboBoxUI) ui;
  }
 
  /**
   * Set the data model for this JComboBox. This un-registers all  listeners
   * associated with the current model, and re-registers them with the new
   * model.
   *
   * @param newDataModel The new data model for this JComboBox
   */
  public void setModel(ComboBoxModel newDataModel)
  {
    // dataModel is null if it this method is called from inside the constructors.
    if (dataModel != null)
      {
        // Prevents unneccessary updates.
        if (dataModel == newDataModel)
          return;
 
        // Removes itself (as DataListener) from the to-be-replaced model.
        dataModel.removeListDataListener(this);
      }
 
    /* Adds itself as a DataListener to the new model.
     * It is intentioned that this operation will fail with a NullPointerException if the
     * caller delivered a null argument.
     */
    newDataModel.addListDataListener(this);
 
    // Stores old data model for event notification.
    ComboBoxModel oldDataModel = dataModel;
    dataModel = newDataModel;
    selectedItemReminder = newDataModel.getSelectedItem();
 
    // Notifies the listeners of the model change.
    firePropertyChange("model", oldDataModel, dataModel);
  }
 
  /**
   * This method returns data model for this comboBox.
   *
   * @return ComboBoxModel containing items for this combo box.
   */
  public ComboBoxModel getModel()
  {
    return dataModel;
  }
 
  /**
   * This method sets JComboBox's popup to be either lightweight or
   * heavyweight. If 'enabled' is true then lightweight popup is used and
   * heavyweight otherwise. By default lightweight popup is used to display
   * this JComboBox's elements.
   *
   * @param enabled indicates if lightweight popup or heavyweight popup should
   *        be used to display JComboBox's elements.
   */
  public void setLightWeightPopupEnabled(boolean enabled)
  {
    lightWeightPopupEnabled = enabled;
  }
 
  /**
   * This method returns whether popup menu that is used to display list of
   * combo box's item is lightWeight or not.
   *
   * @return boolean true if popup menu is lightweight and false otherwise.
   */
  public boolean isLightWeightPopupEnabled()
  {
    return lightWeightPopupEnabled;
  }
 
  /**
   * This method sets editability of the combo box. If combo box  is editable
   * the user can choose component from the combo box list by typing
   * component's name in the editor(JTextfield by default).  Otherwise if not
   * editable, the user should use the list to choose   the component. This
   * method fires PropertyChangeEvents to JComboBox's registered
   * PropertyChangeListeners to indicate that 'editable' property of the
   * JComboBox has changed.
   *
   * @param editable indicates if the JComboBox's textfield should be editable
   *        or not.
   */
  public void setEditable(boolean editable)
  {
    if (isEditable != editable)
      {
        isEditable = editable;
        firePropertyChange("editable", !isEditable, isEditable);
      }
  }
 
  /**
   * Sets number of rows that should be visible in this JComboBox's popup. If
   * this JComboBox's popup has more elements that maximum number or rows
   * then popup will have a scroll pane to allow users to view other
   * elements.
   *
   * @param rowCount number of rows that will be visible in JComboBox's popup.
   */
  public void setMaximumRowCount(int rowCount)
  {
    if (maximumRowCount != rowCount)
      {
        int oldMaximumRowCount = maximumRowCount;
        maximumRowCount = rowCount;
        firePropertyChange("maximumRowCount", oldMaximumRowCount,
                           maximumRowCount);
      }
  }
 
  /**
   * This method returns number of rows visible in the JComboBox's list of
   * items.
   *
   * @return int maximun number of visible rows in the JComboBox's list.
   */
  public int getMaximumRowCount()
  {
    return maximumRowCount;
  }
 
  /**
   * This method sets cell renderer for this JComboBox that will be used to
   * paint combo box's items. The Renderer should only be used only when
   * JComboBox is not editable.  In the case when JComboBox is editable  the
   * editor must be used.  This method also fires PropertyChangeEvent when
   * cellRendered for this JComboBox has changed.
   *
   * @param aRenderer cell renderer that will be used by this JComboBox to
   *        paint its elements.
   */
  public void setRenderer(ListCellRenderer aRenderer)
  {
    if (renderer != aRenderer)
      {
        ListCellRenderer oldRenderer = renderer;
        renderer = aRenderer;
        firePropertyChange("renderer", oldRenderer, renderer);
      }
  }
 
  /**
   * This method returns renderer responsible for rendering selected item in
   * the combo box
   *
   * @return ListCellRenderer
   */
  public ListCellRenderer getRenderer()
  {
    return renderer;
  }
 
  /**
   * Sets editor for this JComboBox
   *
   * @param newEditor ComboBoxEditor for this JComboBox. This method fires
   *        PropertyChangeEvent when 'editor' property is changed.
   */
  public void setEditor(ComboBoxEditor newEditor)
  {
    if (editor == newEditor)
      return;
 
    if (editor != null)
      editor.removeActionListener(this);
 
    ComboBoxEditor oldEditor = editor;
    editor = newEditor;
 
    if (editor != null)
      editor.addActionListener(this);
 
    firePropertyChange("editor", oldEditor, editor);
  }
 
  /**
   * Returns editor component that is responsible for displaying/editing
   * selected item in the combo box.
   *
   * @return ComboBoxEditor
   */
  public ComboBoxEditor getEditor()
  {
    return editor;
  }
 
  /**
   * Forces combo box to select given item
   *
   * @param item element in the combo box to select.
   */
  public void setSelectedItem(Object item)
  {
    dataModel.setSelectedItem(item);
    fireActionEvent();
  }
 
  /**
   * Returns currently selected item in the combo box.
   * The result may be <code>null</code> to indicate that nothing is
   * currently selected.
   *
   * @return element that is currently selected in this combo box.
   */
  public Object getSelectedItem()
  {
    return dataModel.getSelectedItem();
  }
 
  /**
   * Forces JComboBox to select component located in the given index in the
   * combo box.
   * <p>If the index is below -1 or exceeds the upper bound an
   * <code>IllegalArgumentException</code> is thrown.<p/>
   * <p>If the index is -1 then no item gets selected.</p>
   *
   * @param index index specifying location of the component that  should be
   *        selected.
   */
  public void setSelectedIndex(int index)
  {
        if (index < -1 || index >= dataModel.getSize())
      // Fails because index is out of bounds.
      throw new IllegalArgumentException("illegal index: " + index);
    else
       // Selects the item at the given index or clears the selection if the
       // index value is -1.
      setSelectedItem((index == -1) ? null : dataModel.getElementAt(index));
  }
 
  /**
   * Returns index of the item that is currently selected in the combo box. If
   * no item is currently selected, then -1 is returned.
   * <p>
   * Note: For performance reasons you should minimize invocation of this
   * method. If the data model is not an instance of
   * <code>DefaultComboBoxModel</code> the complexity is O(n) where n is the
   * number of elements in the combo box.
   * </p>
   *
   * @return int Index specifying location of the currently selected item in the
   *         combo box or -1 if nothing is selected in the combo box.
   */
  public int getSelectedIndex()
  {
    Object selectedItem = getSelectedItem();
 
    if (selectedItem != null)
      {
        if (dataModel instanceof DefaultComboBoxModel)
          // Uses special method of DefaultComboBoxModel to retrieve the index.
          return ((DefaultComboBoxModel) dataModel).getIndexOf(selectedItem);
        else
          {
            // Iterates over all items to retrieve the index.
            int size = dataModel.getSize();
 
            for (int i = 0; i < size; i++)
              {
                Object o = dataModel.getElementAt(i);
 
                // XXX: Is special handling of ComparableS neccessary?
                if ((selectedItem != null) ? selectedItem.equals(o) : o == null)
                  return i;
              }
          }
      }
 
    // returns that no item is currently selected
    return -1;
  }
 
  /**
   * Returns an object that is used as the display value when calculating the
   * preferred size for the combo box.  This value is, of course, never
   * displayed anywhere.
   *
   * @return The prototype display value (possibly <code>null</code>).
   *
   * @since 1.4
   * @see #setPrototypeDisplayValue(Object)
   */
  public Object getPrototypeDisplayValue()
  {
    return prototypeDisplayValue;
  }
 
  /**
   * Sets the object that is assumed to be the displayed item when calculating
   * the preferred size for the combo box.  A {@link PropertyChangeEvent} (with
   * the name <code>prototypeDisplayValue</code>) is sent to all registered
   * listeners.
   *
   * @param value  the new value (<code>null</code> permitted).
   *
   * @since 1.4
   * @see #getPrototypeDisplayValue()
   */
  public void setPrototypeDisplayValue(Object value)
  {
    Object oldValue = prototypeDisplayValue;
    prototypeDisplayValue = value;
    firePropertyChange("prototypeDisplayValue", oldValue, value);
  }
 
  /**
   * This method adds given element to this JComboBox.
   * <p>A <code>RuntimeException</code> is thrown if the data model is not
   * an instance of {@link MutableComboBoxModel}.</p>
   *
   * @param element element to add
   */
  public void addItem(Object element)
  {
        if (dataModel instanceof MutableComboBoxModel)
      ((MutableComboBoxModel) dataModel).addElement(element);
    else
      throw new RuntimeException("Unable to add the item because the data "
                                 + "model it is not an instance of "
                                 + "MutableComboBoxModel.");
  }
 
  /**
   * Inserts given element at the specified index to this JComboBox.
   * <p>A <code>RuntimeException</code> is thrown if the data model is not
   * an instance of {@link MutableComboBoxModel}.</p>
   *
   * @param element element to insert
   * @param index position where to insert the element
   */
  public void insertItemAt(Object element, int index)
  {
        if (dataModel instanceof MutableComboBoxModel)
      ((MutableComboBoxModel) dataModel).insertElementAt(element, index);
    else
      throw new RuntimeException("Unable to insert the item because the data "
                                 + "model it is not an instance of "
                                 + "MutableComboBoxModel.");
  }
 
  /**
   * This method removes given element from this JComboBox.
   * <p>A <code>RuntimeException</code> is thrown if the data model is not
   * an instance of {@link MutableComboBoxModel}.</p>
   *
   * @param element element to remove
   */
  public void removeItem(Object element)
  {
        if (dataModel instanceof MutableComboBoxModel)
      ((MutableComboBoxModel) dataModel).removeElement(element);
    else
      throw new RuntimeException("Unable to remove the item because the data "
                                 + "model it is not an instance of "
                                 + "MutableComboBoxModel.");
  }
 
  /**
   * This method remove element location in the specified index in the
   * JComboBox.
   * <p>A <code>RuntimeException</code> is thrown if the data model is not
   * an instance of {@link MutableComboBoxModel}.</p>
   *
   * @param index index specifying position of the element to remove
   */
  public void removeItemAt(int index)
  {
    if (dataModel instanceof MutableComboBoxModel)
      ((MutableComboBoxModel) dataModel).removeElementAt(index);
    else
      throw new RuntimeException("Unable to remove the item because the data "
                                 + "model it is not an instance of "
                                 + "MutableComboBoxModel.");
  }
 
  /**
   * This method removes all elements from this JComboBox.
   * <p>
   * A <code>RuntimeException</code> is thrown if the data model is not an
   * instance of {@link MutableComboBoxModel}.
   * </p>
   */
  public void removeAllItems()
  {
    if (dataModel instanceof DefaultComboBoxModel)
      // Uses special method if we have a DefaultComboBoxModel.
      ((DefaultComboBoxModel) dataModel).removeAllElements();
    else if (dataModel instanceof MutableComboBoxModel)
      {
        // Iterates over all items and removes each.
        MutableComboBoxModel mcbm = (MutableComboBoxModel) dataModel;
 
         // We intentionally remove the items backwards to support models which
         // shift their content to the beginning (e.g. linked lists)
        for (int i = mcbm.getSize() - 1; i >= 0; i--)
          mcbm.removeElementAt(i);
      }
    else
      throw new RuntimeException("Unable to remove the items because the data "
                                 + "model it is not an instance of "
                                 + "MutableComboBoxModel.");
  }
 
  /**
   * This method displays popup with list of combo box's items on the screen
   */
  public void showPopup()
  {
    setPopupVisible(true);
  }
 
  /**
   * This method hides popup containing list of combo box's items
   */
  public void hidePopup()
  {
    setPopupVisible(false);
  }
 
  /**
   * This method either displayes or hides the popup containing  list of combo
   * box's items.
   *
   * @param visible show popup if 'visible' is true and hide it otherwise
   */
  public void setPopupVisible(boolean visible)
  {
    getUI().setPopupVisible(this, visible);
  }
 
  /**
   * Checks if popup is currently visible on the screen.
   *
   * @return boolean true if popup is visible and false otherwise
   */
  public boolean isPopupVisible()
  {
    return getUI().isPopupVisible(this);
  }
 
  /**
   * This method sets actionCommand to the specified string. ActionEvent fired
   * to this JComboBox  registered ActionListeners will contain this
   * actionCommand.
   *
   * @param aCommand new action command for the JComboBox's ActionEvent
   */
  public void setActionCommand(String aCommand)
  {
    actionCommand = aCommand;
  }
 
  /**
   * Returns actionCommand associated with the ActionEvent fired by the
   * JComboBox to its registered ActionListeners.
   *
   * @return String actionCommand for the ActionEvent
   */
  public String getActionCommand()
  {
    return actionCommand;
  }
 
  /**
   * setAction
   *
   * @param a action to set
   */
  public void setAction(Action a)
  {
    Action old = action;
    action = a;
    configurePropertiesFromAction(action);
    if (action != null)
      // FIXME: remove from old action and add to new action
      // PropertyChangeListener to listen to changes in the action
      addActionListener(action);
  }
 
  /**
   * This method returns Action that is invoked when selected item is changed
   * in the JComboBox.
   *
   * @return Action
   */
  public Action getAction()
  {
    return action;
  }
 
  /**
   * Configure properties of the JComboBox by reading properties of specified
   * action. This method always sets the comboBox's "enabled" property to the
   * value of the Action's "enabled" property.
   *
   * @param a An Action to configure the combo box from
   */
  protected void configurePropertiesFromAction(Action a)
  {
    if (a == null)
      {
        setEnabled(true);
        setToolTipText(null);
      }
    else
      {
        setEnabled(a.isEnabled());
        setToolTipText((String) (a.getValue(Action.SHORT_DESCRIPTION)));
      }
  }
 
  /**
   * Creates PropertyChangeListener to listen for the changes in comboBox's
   * action properties.
   *
   * @param action action to listen to for property changes
   *
   * @return a PropertyChangeListener that listens to changes in
   *         action properties.
   */
  protected PropertyChangeListener createActionPropertyChangeListener(Action action)
  {
    return new PropertyChangeListener()
      {
        public void propertyChange(PropertyChangeEvent e)
        {
          Action act = (Action) (e.getSource());
          configurePropertiesFromAction(act);
        }
      };
  }
 
  /**
   * This method fires ItemEvent to this JComboBox's registered ItemListeners.
   * This method is invoked when currently selected item in this combo box
   * has changed.
   *
   * @param e the ItemEvent describing the change in the combo box's
   *        selection.
   */
  protected void fireItemStateChanged(ItemEvent e)
  {
    ItemListener[] ll = getItemListeners();
 
    for (int i = 0; i < ll.length; i++)
      ll[i].itemStateChanged(e);
  }
 
  /**
   * This method fires ActionEvent to this JComboBox's registered
   * ActionListeners. This method is invoked when user explicitly changes
   * currently selected item.
   */
  protected void fireActionEvent()
  {
    ActionListener[] ll = getActionListeners();
 
    for (int i = 0; i < ll.length; i++)
      ll[i].actionPerformed(new ActionEvent(this,
                                            ActionEvent.ACTION_PERFORMED,
                                            actionCommand));
  }
 
  /**
   * Fires a popupMenuCanceled() event to all <code>PopupMenuListeners</code>.
   *
   * Note: This method is intended for use by plaf classes only.
   */
  public void firePopupMenuCanceled()
  {
    PopupMenuListener[] listeners = getPopupMenuListeners();
    PopupMenuEvent e = new PopupMenuEvent(this);
    for (int i = 0; i < listeners.length; i++)
      listeners[i].popupMenuCanceled(e);
  }
 
  /**
   * Fires a popupMenuWillBecomeInvisible() event to all
   * <code>PopupMenuListeners</code>.
   *
   * Note: This method is intended for use by plaf classes only.
   */
  public void firePopupMenuWillBecomeInvisible()
  {
    PopupMenuListener[] listeners = getPopupMenuListeners();
    PopupMenuEvent e = new PopupMenuEvent(this);
    for (int i = 0; i < listeners.length; i++)
      listeners[i].popupMenuWillBecomeInvisible(e);
  }
 
  /**
   * Fires a popupMenuWillBecomeVisible() event to all
   * <code>PopupMenuListeners</code>.
   *
   * Note: This method is intended for use by plaf classes only.
   */
  public void firePopupMenuWillBecomeVisible()
  {
    PopupMenuListener[] listeners = getPopupMenuListeners();
    PopupMenuEvent e = new PopupMenuEvent(this);
    for (int i = 0; i < listeners.length; i++)
      listeners[i].popupMenuWillBecomeVisible(e);
  }
 
  /**
   * This method is invoked whenever selected item changes in the combo box's
   * data model. It fires ItemEvent and ActionEvent to all registered
   * ComboBox's ItemListeners and ActionListeners respectively, indicating
   * the change.
   */
  protected void selectedItemChanged()
  {
    // Fire ItemEvent to indicated that previously selected item is now
    // deselected
    if (selectedItemReminder != null)
      fireItemStateChanged(new ItemEvent(this, ItemEvent.ITEM_STATE_CHANGED,
                                         selectedItemReminder,
                                         ItemEvent.DESELECTED));
 
    // Fire ItemEvent to indicate that new item is selected
    Object newSelection = getSelectedItem();
    if (newSelection != null)
      fireItemStateChanged(new ItemEvent(this, ItemEvent.ITEM_STATE_CHANGED,
                                         newSelection, ItemEvent.SELECTED));
 
    // Fire Action Event to JComboBox's registered listeners
    fireActionEvent();
 
    selectedItemReminder = newSelection;
  }
 
  /**
   * Returns Object array of size 1 containing currently selected element in
   * the JComboBox.
   *
   * @return Object[] Object array of size 1 containing currently selected
   *         element in the JComboBox.
   */
  public Object[] getSelectedObjects()
  {
    return new Object[] { getSelectedItem() };
  }
 
  /**
   * This method handles actionEvents fired by the ComboBoxEditor. It changes
   * this JComboBox's selection to the new value currently in the editor and
   * hides list of combo box items.
   *
   * @param e the ActionEvent
   */
  public void actionPerformed(ActionEvent e)
  {
    setSelectedItem(getEditor().getItem());
    setPopupVisible(false);
  }
 
  /**
   * This method selects item in this combo box that matches specified
   * specified keyChar and returns true if such item is found. Otherwise
   * false is returned.
   *
   * @param keyChar character indicating which item in the combo box should be
   *        selected.
   *
   * @return boolean true if item corresponding to the specified keyChar
   *         exists in the combo box. Otherwise false is returned.
   */
  public boolean selectWithKeyChar(char keyChar)
  {
    if (keySelectionManager == null)
      {
        keySelectionManager = createDefaultKeySelectionManager();
      }
 
    int index = keySelectionManager.selectionForKey(keyChar, getModel());
    boolean retVal = false;
    if (index >= 0)
      {
        setSelectedIndex(index);
        retVal = true;
      }
    return retVal;
  }
 
  /**
   * The part of implementation of ListDataListener interface. This method is
   * invoked when some items where added to the JComboBox's data model.
   *
   * @param event ListDataEvent describing the change
   */
  public void intervalAdded(ListDataEvent event)
  {
    // FIXME: Need to implement
    repaint();
  }
 
  /**
   * The part of implementation of ListDataListener interface. This method is
   * invoked when some items where removed from the JComboBox's data model.
   *
   * @param event ListDataEvent describing the change.
   */
  public void intervalRemoved(ListDataEvent event)
  {
    // FIXME: Need to implement
    repaint();
  }
 
  /**
   * The part of implementation of ListDataListener interface. This method is
   * invoked when contents of the JComboBox's  data model changed.
   *
   * @param event ListDataEvent describing the change
   */
  public void contentsChanged(ListDataEvent event)
  {
    // if first and last index of the given ListDataEvent are both -1,
    // then it indicates that selected item in the combo box data model
    // have changed.
    if (event.getIndex0() == -1 && event.getIndex1() == -1)
      selectedItemChanged();
  }
 
  /**
   * This method disables or enables JComboBox. If the JComboBox is enabled,
   * then user is able to make item choice, otherwise if JComboBox is
   * disabled then user is not able to make a selection.
   *
   * @param enabled if 'enabled' is true then enable JComboBox and disable it
   */
  public void setEnabled(boolean enabled)
  {
    boolean oldEnabled = super.isEnabled();
    if (enabled != oldEnabled)
      {
        super.setEnabled(enabled);
        firePropertyChange("enabled", oldEnabled, enabled);
      }
  }
 
  /**
   * This method initializes specified ComboBoxEditor to display given item.
   *
   * @param anEditor ComboBoxEditor to initialize
   * @param anItem Item that should displayed in the specified editor
   */
  public void configureEditor(ComboBoxEditor anEditor, Object anItem)
  {
    anEditor.setItem(anItem);
  }
 
  /**
   * This method is fired whenever a key is pressed with the combo box
   * in focus
   *
   * @param e The KeyEvent indicating which key was pressed.
   */
  public void processKeyEvent(KeyEvent e)
  {
    if (e.getKeyCode() == KeyEvent.VK_TAB)
      setPopupVisible(false);
    else
      super.processKeyEvent(e);
  }
 
  /**
   * setKeySelectionManager
   *
   * @param aManager
   */
  public void setKeySelectionManager(KeySelectionManager aManager)
  {
    keySelectionManager = aManager;
  }
 
  /**
   * getKeySelectionManager
   *
   * @return JComboBox.KeySelectionManager
   */
  public KeySelectionManager getKeySelectionManager()
  {
    return keySelectionManager;
  }
 
  /**
   * This method returns number of elements in this JComboBox
   *
   * @return int number of elements in this JComboBox
   */
  public int getItemCount()
  {
    return dataModel.getSize();
  }
 
  /**
   * Returns elements located in the combo box at the given index.
   *
   * @param index index specifying location of the component to  return.
   *
   * @return component in the combo box that is located in  the given index.
   */
  public Object getItemAt(int index)
  {
    return dataModel.getElementAt(index);
  }
 
  /**
   * createDefaultKeySelectionManager
   *
   * @return KeySelectionManager
   */
  protected KeySelectionManager createDefaultKeySelectionManager()
  {
    return new DefaultKeySelectionManager();
  }
 
  /**
   * Returns an implementation-dependent string describing the attributes of
   * this <code>JComboBox</code>.
   *
   * @return A string describing the attributes of this <code>JComboBox</code>
   *         (never <code>null</code>).
   */
  protected String paramString()
  {
    String superParamStr = super.paramString();
    CPStringBuilder sb = new CPStringBuilder();
    sb.append(",isEditable=").append(isEditable());
    sb.append(",lightWeightPopupEnabled=").append(isLightWeightPopupEnabled());
    sb.append(",maximumRowCount=").append(getMaximumRowCount());
 
    sb.append(",selectedItemReminder=");
    if (selectedItemReminder != null)
      sb.append(selectedItemReminder);
    return superParamStr + sb.toString();
  }
 
  /**
   * Returns the object that provides accessibility features for this
   * <code>JComboBox</code> component.
   *
   * @return The accessible context (an instance of
   *         {@link AccessibleJComboBox}).
   */
  public AccessibleContext getAccessibleContext()
  {
    if (accessibleContext == null)
      accessibleContext = new AccessibleJComboBox();
 
    return accessibleContext;
  }
 
  /**
   * This methods adds specified ActionListener to this JComboBox.
   *
   * @param listener to add
   */
  public void addActionListener(ActionListener listener)
  {
    listenerList.add(ActionListener.class, listener);
  }
 
  /**
   * This method removes specified ActionListener from this JComboBox.
   *
   * @param listener ActionListener
   */
  public void removeActionListener(ActionListener listener)
  {
    listenerList.remove(ActionListener.class, listener);
  }
 
  /**
   * This method returns array of ActionListeners that are registered with
   * this JComboBox.
   *
   * @since 1.4
   */
  public ActionListener[] getActionListeners()
  {
    return (ActionListener[]) getListeners(ActionListener.class);
  }
 
  /**
   * This method registers given ItemListener with this JComboBox
   *
   * @param listener to remove
   */
  public void addItemListener(ItemListener listener)
  {
    listenerList.add(ItemListener.class, listener);
  }
 
  /**
   * This method unregisters given ItemListener from this JComboBox
   *
   * @param listener to remove
   */
  public void removeItemListener(ItemListener listener)
  {
    listenerList.remove(ItemListener.class, listener);
  }
 
  /**
   * This method returns array of ItemListeners that are registered with this
   * JComboBox.
   *
   * @since 1.4
   */
  public ItemListener[] getItemListeners()
  {
    return (ItemListener[]) getListeners(ItemListener.class);
  }
 
  /**
   * Adds PopupMenuListener to combo box to listen to the events fired by the
   * combo box's popup menu containing its list of items
   *
   * @param listener to add
   */
  public void addPopupMenuListener(PopupMenuListener listener)
  {
    listenerList.add(PopupMenuListener.class, listener);
  }
 
  /**
   * Removes PopupMenuListener to combo box to listen to the events fired by
   * the combo box's popup menu containing its list of items
   *
   * @param listener to add
   */
  public void removePopupMenuListener(PopupMenuListener listener)
  {
    listenerList.remove(PopupMenuListener.class, listener);
  }
 
  /**
   * Returns array of PopupMenuListeners that are registered with  combo box.
   */
  public PopupMenuListener[] getPopupMenuListeners()
  {
    return (PopupMenuListener[]) getListeners(PopupMenuListener.class);
  }
 
  /**
   * Accessibility support for <code>JComboBox</code>.
   */
  protected class AccessibleJComboBox extends AccessibleJComponent
    implements AccessibleAction, AccessibleSelection
  {
    private static final long serialVersionUID = 8217828307256675666L;
 
    /**
     * @specnote This constructor was protected in 1.4, but made public
     * in 1.5.
     */
    public AccessibleJComboBox()
    {
      // Nothing to do here.
    }
 
    /**
     * Returns the number of accessible children of this object. The
     * implementation of AccessibleJComboBox delegates this call to the UI
     * of the associated JComboBox.
     *
     * @return the number of accessible children of this object
     *
     * @see ComponentUI#getAccessibleChildrenCount(JComponent)
     */
    public int getAccessibleChildrenCount()
    {
      ComponentUI ui = getUI();
      int count;
      if (ui != null)
        count = ui.getAccessibleChildrenCount(JComboBox.this);
      else
        count = super.getAccessibleChildrenCount();
      return count;
    }
 
    /**
     * Returns the number of accessible children of this object. The
     * implementation of AccessibleJComboBox delegates this call to the UI
     * of the associated JComboBox.
     *
     * @param index the index of the accessible child to fetch
     *
     * @return the number of accessible children of this object
     *
     * @see ComponentUI#getAccessibleChild(JComponent, int)
     */
    public Accessible getAccessibleChild(int index)
    {
      ComponentUI ui = getUI();
      Accessible child = null;
      if (ui != null)
        child = ui.getAccessibleChild(JComboBox.this, index);
      else
        child = super.getAccessibleChild(index);
      return child;
    }
 
    /**
     * Returns the AccessibleSelection object associated with this object.
     * AccessibleJComboBoxes handle their selection themselves, so this
     * always returns <code>this</code>.
     *
     * @return the AccessibleSelection object associated with this object
     */
    public AccessibleSelection getAccessibleSelection()
    {
      return this;
    }
 
    /**
     * Returns the accessible selection from this AccssibleJComboBox.
     *
     * @param index the index of the selected child to fetch
     *
     * @return the accessible selection from this AccssibleJComboBox
     */
    public Accessible getAccessibleSelection(int index)
    {
      // Get hold of the actual popup.
      Accessible popup = getUI().getAccessibleChild(JComboBox.this, 0);
      Accessible selected = null;
      if (popup != null && popup instanceof ComboPopup)
        {
          ComboPopup cPopup = (ComboPopup) popup;
          // Query the list for the currently selected child.
          JList l = cPopup.getList();
          AccessibleContext listCtx = l.getAccessibleContext();
          if (listCtx != null)
            {
              AccessibleSelection s = listCtx.getAccessibleSelection();
              if (s != null)
                {
                  selected = s.getAccessibleSelection(index);
                }
            }
        }
      return selected;
    }
 
    /**
     * Returns <code>true</code> if the accessible child with the specified
     * <code>index</code> is selected, <code>false</code> otherwise.
     *
     * @param index the index of the accessible child
     *
     * @return <code>true</code> if the accessible child with the specified
     *         <code>index</code> is selected, <code>false</code> otherwise
     */
    public boolean isAccessibleChildSelected(int index)
    {
      return getSelectedIndex() == index;
    }
 
    /**
     * Returns the accessible role for the <code>JComboBox</code> component.
     *
     * @return {@link AccessibleRole#COMBO_BOX}.
     */
    public AccessibleRole getAccessibleRole()
    {
      return AccessibleRole.COMBO_BOX;
    }
 
    /**
     * Returns the accessible action associated to this accessible object.
     * AccessibleJComboBox implements its own AccessibleAction, so this
     * method returns <code>this</code>.
     *
     * @return the accessible action associated to this accessible object
     */
    public AccessibleAction getAccessibleAction()
    {
      return this;
    }
 
    /**
     * Returns the description of the specified action. AccessibleJComboBox
     * implements 1 action (toggle the popup menu) and thus returns
     * <code>UIManager.getString("ComboBox.togglePopupText")</code>
     *
     * @param actionIndex the index of the action for which to return the
     *        description
     *
     * @return the description of the specified action
     */
    public String getAccessibleActionDescription(int actionIndex)
    {
      return UIManager.getString("ComboBox.togglePopupText");
    }
 
    /**
     * Returns the number of accessible actions that can be performed by
     * this object. AccessibleJComboBox implement s one accessible action
     * (toggle the popup menu), so this method always returns <code>1</code>.
     *
     * @return the number of accessible actions that can be performed by
     *         this object
     */
    public int getAccessibleActionCount()
    {
      return 1;
    }
 
    /**
     * Performs the accessible action with the specified index.
     * AccessibleJComboBox has 1 accessible action
     * (<code>actionIndex == 0</code>), which is to toggle the
     * popup menu. All other action indices have no effect and return
     * <code<>false</code>.
     *
     * @param actionIndex the index of the action to perform
     *
     * @return <code>true</code> if the action has been performed,
     *         <code>false</code> otherwise
     */
    public boolean doAccessibleAction(int actionIndex)
    {
      boolean actionPerformed = false;
      if (actionIndex == 0)
        {
          setPopupVisible(! isPopupVisible());
          actionPerformed = true;
        }
      return actionPerformed;
    }
 
    /**
     * Returns the number of selected accessible children of this object. This
     * returns <code>1</code> if the combobox has a selected entry,
     * <code>0</code> otherwise.
     *
     * @return the number of selected accessible children of this object
     */
    public int getAccessibleSelectionCount()
    {
      Object sel = getSelectedItem();
      int count = 0;
      if (sel != null)
        count = 1;
      return count;
    }
 
    /**
     * Sets the current selection to the specified <code>index</code>.
     *
     * @param index the index to set as selection
     */
    public void addAccessibleSelection(int index)
    {
      setSelectedIndex(index);
    }
 
    /**
     * Removes the specified index from the current selection.
     *
     * @param index the index to remove from the selection
     */
    public void removeAccessibleSelection(int index)
    {
      if (getSelectedIndex() == index)
        clearAccessibleSelection();
    }
 
    /**
     * Clears the current selection.
     */
    public void clearAccessibleSelection()
    {
      setSelectedIndex(-1);
    }
 
    /**
     * Multiple selection is not supported by AccessibleJComboBox, so this
     * does nothing.
     */
    public void selectAllAccessibleSelection()
    {
      // Nothing to do here.
    }
  }
 
  private class DefaultKeySelectionManager
      implements KeySelectionManager
  {
 
    public int selectionForKey(char aKey, ComboBoxModel aModel)
    {
      int selectedIndex = getSelectedIndex();
 
      // Start at currently selected item and iterate to end of list
      for (int i = selectedIndex + 1; i < aModel.getSize(); i++)
        {
          String nextItem = aModel.getElementAt(i).toString();
 
          if (nextItem.charAt(0) == aKey)
            return i;
        }
 
      // Wrap to start of list if no match yet
      for (int i = 0; i <= selectedIndex; i++)
        {
          String nextItem = aModel.getElementAt(i).toString();
 
          if (nextItem.charAt(0) == aKey)
            return i;
        }
 
      return - 1;
    }
  }
}