* be added to the combo box.     *      * @return an instance of a <code>PropertyChangeListener</code> or null     */    protected PropertyChangeListener createPropertyChangeListener() {        return getHandler();    }    /**     * Creates a layout manager for managing the components which make up the      * combo box.     *      * @return an instance of a layout manager     */    protected LayoutManager createLayoutManager() {        return getHandler();    }    /**     * Creates the default renderer that will be used in a non-editiable combo      * box. A default renderer will used only if a renderer has not been      * explicitly set with <code>setRenderer</code>.     *      * @return a <code>ListCellRender</code> used for the combo box     * @see javax.swing.JComboBox#setRenderer     */    protected ListCellRenderer createRenderer() {        return new BasicComboBoxRenderer.UIResource();    }    /**     * Creates the default editor that will be used in editable combo boxes.       * A default editor will be used only if an editor has not been      * explicitly set with <code>setEditor</code>.     *     * @return a <code>ComboBoxEditor</code> used for the combo box     * @see javax.swing.JComboBox#setEditor     */    protected ComboBoxEditor createEditor() {        return new BasicComboBoxEditor.UIResource();    }    /**     * Returns the shared listener.     */    private Handler getHandler() {        if (handler == null) {            handler = new Handler();        }        return handler;    }    //    // end UI Initialization    //======================    //======================    // begin Inner classes    //    /**     * This listener checks to see if the key event isn't a navigation key.  If     * it finds a key event that wasn't a navigation key it dispatches it to     * JComboBox.selectWithKeyChar() so that it can do type-ahead.     *     * This public inner class should be treated as protected.      * Instantiate it only within subclasses of      * <code>BasicComboBoxUI</code>.     */    public class KeyHandler extends KeyAdapter {        public void keyPressed( KeyEvent e ) {            getHandler().keyPressed(e);        }    }    /**     * This listener hides the popup when the focus is lost.  It also repaints     * when focus is gained or lost.     *     * This public inner class should be treated as protected.      * Instantiate it only within subclasses of      * <code>BasicComboBoxUI</code>.     */    public class FocusHandler implements FocusListener {        public void focusGained( FocusEvent e ) {            getHandler().focusGained(e);        }        public void focusLost( FocusEvent e ) {            getHandler().focusLost(e);        }    }    /**     * This listener watches for changes in the      * <code>ComboBoxModel</code>.     * <p>     * This public inner class should be treated as protected.      * Instantiate it only within subclasses of      * <code>BasicComboBoxUI</code>.     *     * @see #createListDataListener     */    public class ListDataHandler implements ListDataListener {        public void contentsChanged( ListDataEvent e ) {            getHandler().contentsChanged(e);	}        public void intervalAdded( ListDataEvent e ) {            getHandler().intervalAdded(e);        }        public void intervalRemoved( ListDataEvent e ) {            getHandler().intervalRemoved(e);        }    }    /**     * This listener watches for changes to the selection in the      * combo box.     * <p>     * This public inner class should be treated as protected.      * Instantiate it only within subclasses of      * <code>BasicComboBoxUI</code>.     *     * @see #createItemListener     */    public class ItemHandler implements ItemListener {	// This class used to implement behavior which is now redundant.        public void itemStateChanged(ItemEvent e) {}    }    /**     * This listener watches for bound properties that have changed in the     * combo box.      * <p>     * Subclasses which wish to listen to combo box property changes should     * call the superclass methods to ensure that the combo box ui correctly      * handles property changes.     * <p>     * This public inner class should be treated as protected.      * Instantiate it only within subclasses of      * <code>BasicComboBoxUI</code>.     *      * @see #createPropertyChangeListener     */    public class PropertyChangeHandler implements PropertyChangeListener {        public void propertyChange(PropertyChangeEvent e) {            getHandler().propertyChange(e);        }    }    // Syncronizes the ToolTip text for the components within the combo box to be the     // same value as the combo box ToolTip text.    private void updateToolTipTextForChildren() {        Component[] children = comboBox.getComponents();        for ( int i = 0; i < children.length; ++i ) {            if ( children[i] instanceof JComponent ) {                ((JComponent)children[i]).setToolTipText( comboBox.getToolTipText() );            }        }    }    /**     * This layout manager handles the 'standard' layout of combo boxes.  It puts     * the arrow button to the right and the editor to the left.  If there is no     * editor it still keeps the arrow button to the right.     *     * This public inner class should be treated as protected.      * Instantiate it only within subclasses of      * <code>BasicComboBoxUI</code>.     */    public class ComboBoxLayoutManager implements LayoutManager {        public void addLayoutComponent(String name, Component comp) {}        public void removeLayoutComponent(Component comp) {}        public Dimension preferredLayoutSize(Container parent) {            return getHandler().preferredLayoutSize(parent);        }        public Dimension minimumLayoutSize(Container parent) {            return getHandler().minimumLayoutSize(parent);        }        public void layoutContainer(Container parent) {            getHandler().layoutContainer(parent);        }    }    //    // end Inner classes    //====================    //===============================    // begin Sub-Component Management    //    /**     * Creates and initializes the components which make up the     * aggregate combo box. This method is called as part of the UI     * installation process.     */    protected void installComponents() {        arrowButton = createArrowButton();        comboBox.add( arrowButton );        if (arrowButton != null)  {            configureArrowButton();        }        if ( comboBox.isEditable() ) {            addEditor();        }        comboBox.add( currentValuePane );    }    /**     * The aggregate components which compise the combo box are      * unregistered and uninitialized. This method is called as part of the     * UI uninstallation process.     */    protected void uninstallComponents() {        if ( arrowButton != null ) {            unconfigureArrowButton();        }        if ( editor != null ) {            unconfigureEditor();        }        comboBox.removeAll(); // Just to be safe.        arrowButton = null;    }    /**     * This public method is implementation specific and should be private.     * do not call or override. To implement a specific editor create a     * custom <code>ComboBoxEditor</code>     *     * @see #createEditor     * @see javax.swing.JComboBox#setEditor     * @see javax.swing.ComboBoxEditor     */    public void addEditor() {        removeEditor();        editor = comboBox.getEditor().getEditorComponent();        if ( editor != null ) {            configureEditor();             comboBox.add(editor);            if(comboBox.isFocusOwner()) {                // Switch focus to the editor component                editor.requestFocusInWindow();            }        }    }    /**     * This public method is implementation specific and should be private.     * do not call or override.      *     * @see #addEditor     */    public void removeEditor() {        if ( editor != null ) {            unconfigureEditor();            comboBox.remove( editor );	    editor = null;        }    }    /**     * This protected method is implementation specific and should be private.     * do not call or override.     *      * @see #addEditor     */    protected void configureEditor() {        // Should be in the same state as the combobox        editor.setEnabled(comboBox.isEnabled());        editor.setFont( comboBox.getFont() );        if (focusListener != null) {            editor.addFocusListener(focusListener);        }	editor.addFocusListener( getHandler() );	comboBox.getEditor().addActionListener(getHandler());        if(editor instanceof JComponent) {            ((JComponent)editor).putClientProperty("doNotCancelPopup",                                                   HIDE_POPUP_KEY);            ((JComponent)editor).setInheritsPopupMenu(true);        }        comboBox.configureEditor(comboBox.getEditor(),comboBox.getSelectedItem());    }    /**     * This protected method is implementation specific and should be private.     * Do not call or override.     *      * @see #addEditor     */    protected void unconfigureEditor() {        if (focusListener != null) {            editor.removeFocusListener(focusListener);        }        editor.removeFocusListener(getHandler());        comboBox.getEditor().removeActionListener(getHandler());    }    /**     * This public method is implementation specific and should be private. Do     * not call or override.     *     * @see #createArrowButton     */    public void configureArrowButton() {        if ( arrowButton != null ) {            arrowButton.setEnabled( comboBox.isEnabled() );            arrowButton.setRequestFocusEnabled(false);	    arrowButton.addMouseListener( popup.getMouseListener() );	    arrowButton.addMouseMotionListener( popup.getMouseMotionListener() );            arrowButton.resetKeyboardActions();            arrowButton.putClientProperty("doNotCancelPopup", HIDE_POPUP_KEY);            arrowButton.setInheritsPopupMenu(true);        }    }    /**     * This public method is implementation specific and should be private. Do     * not call or override.     *     * @see #createArrowButton     */    public void unconfigureArrowButton() {        if ( arrowButton != null ) {	    arrowButton.removeMouseListener( popup.getMouseListener() );	    arrowButton.removeMouseMotionListener( popup.getMouseMotionListener() );        }    }    /**     * Creates an button which will be used as the control to show or hide     * the popup portion of the combo box.     *     * @return a button which represents the popup control     */    protected JButton createArrowButton() {        JButton button = new BasicArrowButton(BasicArrowButton.SOUTH,				    UIManager.getColor("ComboBox.buttonBackground"),				    UIManager.getColor("ComboBox.buttonShadow"),				    UIManager.getColor("ComboBox.buttonDarkShadow"),				    UIManager.getColor("ComboBox.buttonHighlight"));        button.setName("ComboBox.arrowButton");        return button;    }    //    // end Sub-Component Management    //===============================    //================================    // begin ComboBoxUI Implementation    //    /**     * Tells if the popup is visible or not.     */    public boolean isPopupVisible( JComboBox c ) {        return popup.isVisible();    }    /**     * Hides the popup.     */    public void setPopupVisible( JComboBox c, boolean v ) {        if ( v ) {            popup.show();        } else {            popup.hide();        }    }    /**     * Determines if the JComboBox is focus traversable.  If the JComboBox is editable     * this returns false, otherwise it returns true.     */    public boolean isFocusTraversable( JComboBox c ) {        return !comboBox.isEditable();    }    //    // end ComboBoxUI Implementation    //==============================    //=================================    // begin ComponentUI Implementation    public void paint( Graphics g, JComponent c ) {        hasFocus = comboBox.hasFocus();        if ( !comboBox.isEditable() ) {            Rectangle r = rectangleForCurrentValue();            paintCurrentValueBackground(g,r,hasFocus);            paintCurrentValue(g,r,hasFocus);        }    }    public Dimension getPreferredSize( JComponent c ) {	return getMinimumSize(c);    }    /**      * The minumum size is the size of the display area plus insets plus the button.     */    public Dimension getMinimumSize( JComponent c ) {        if ( !isMinimumSizeDirty ) {            return new Dimension(cachedMinimumSize);        }        Dimension size = getDisplaySize();        Insets insets = getInsets();        size.height += insets.top + insets.bottom;        int buttonSize = size.height - (insets.top + insets.bottom);        size.width +=  insets.left + insets.right + buttonSize;        cachedMinimumSize.setSize( size.width, size.height );         isMinimumSizeDirty = false;        return new Dimension(size);