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/* BasicComboPopup.java --

   Copyright (C) 2004, 2005  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

the 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, but

WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

General Public License for more details.

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

along with GNU Classpath; see the file COPYING.  If not, write to the

Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

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

conditions of the GNU General Public License cover the whole

combination.

As a special exception, the copyright holders of this library give you

permission to link this library with independent modules to produce an

executable, regardless of the license terms of these independent

modules, and to copy and distribute the resulting executable under

terms of your choice, provided that you also meet, for each linked

independent module, the terms and conditions of the license of that

module.  An independent module is a module which is not derived from

or based on this library.  If you modify this library, you may extend

this exception to your version of the library, but you are not

obligated to do so.  If you do not wish to do so, delete this

exception statement from your version. */

package javax.swing.plaf.basic;

import java.awt.Color;

import java.awt.Component;

import java.awt.Dimension;

import java.awt.Insets;

import java.awt.Point;

import java.awt.Rectangle;

import java.awt.event.ItemEvent;

import java.awt.event.ItemListener;

import java.awt.event.KeyAdapter;

import java.awt.event.KeyEvent;

import java.awt.event.KeyListener;

import java.awt.event.MouseAdapter;

import java.awt.event.MouseEvent;

import java.awt.event.MouseListener;

import java.awt.event.MouseMotionAdapter;

import java.awt.event.MouseMotionListener;

import java.beans.PropertyChangeEvent;

import java.beans.PropertyChangeListener;

import javax.swing.BorderFactory;

import javax.swing.ComboBoxModel;

import javax.swing.JComboBox;

import javax.swing.JList;

import javax.swing.JPopupMenu;

import javax.swing.JScrollBar;

import javax.swing.JScrollPane;

import javax.swing.ListCellRenderer;

import javax.swing.ListSelectionModel;

import javax.swing.MenuSelectionManager;

import javax.swing.SwingConstants;

import javax.swing.SwingUtilities;

import javax.swing.Timer;

import javax.swing.UIManager;

import javax.swing.event.ListDataEvent;

import javax.swing.event.ListDataListener;

import javax.swing.event.ListSelectionEvent;

import javax.swing.event.ListSelectionListener;

import javax.swing.event.PopupMenuEvent;

import javax.swing.event.PopupMenuListener;

/**

 * UI Delegate for ComboPopup

 *

 * @author Olga Rodimina

 */

public class BasicComboPopup extends JPopupMenu implements ComboPopup

{

  /* Timer for autoscrolling */

  protected Timer autoscrollTimer;

  /** ComboBox associated with this popup */

  protected JComboBox comboBox;

  /** FIXME: Need to document */

  protected boolean hasEntered;

  /**

   * Indicates whether the scroll bar located in popup menu with comboBox's

   * list of items is currently autoscrolling. This happens when mouse event

   * originated in the combo box and is dragged outside of its bounds

   */

  protected boolean isAutoScrolling;

  /** ItemListener listening to the selection changes in the combo box */

  protected ItemListener itemListener;

  /** This listener is not used */

  protected KeyListener keyListener;

  /** JList which is used to display item is the combo box */

  protected JList list;

  /** This listener is not used */

  protected ListDataListener listDataListener;

  /**

   * MouseListener listening to mouse events occuring in the  combo box's

   * list.

   */

  protected MouseListener listMouseListener;

  /**

   * MouseMotionListener listening to mouse motion events occuring  in the

   * combo box's list

   */

  protected MouseMotionListener listMouseMotionListener;

  /** This listener is not used */

  protected ListSelectionListener listSelectionListener;

  /** MouseListener listening to mouse events occuring in the combo box */

  protected MouseListener mouseListener;

  /**

   * MouseMotionListener listening to mouse motion events occuring in the

   * combo box

   */

  protected MouseMotionListener mouseMotionListener;

  /**

   * PropertyChangeListener listening to changes occuring in the bound

   * properties of the combo box

   */

  protected PropertyChangeListener propertyChangeListener;

  /** direction for scrolling down list of combo box's items */

  protected static final int SCROLL_DOWN = 1;

  /** direction for scrolling up list of combo box's items */

  protected static final int SCROLL_UP = 0;

  /** Indicates auto scrolling direction */

  protected int scrollDirection;

  /** JScrollPane that contains list portion of the combo box */

  protected JScrollPane scroller;

  /** This field is not used */

  protected boolean valueIsAdjusting;

  /**

   * Creates a new BasicComboPopup object.

   *

   * @param comboBox the combo box with which this popup should be associated

   */

  public BasicComboPopup(JComboBox comboBox)

  {

    this.comboBox = comboBox;

    mouseListener = createMouseListener();

    mouseMotionListener = createMouseMotionListener();

    keyListener = createKeyListener();

    list = createList();

    configureList();

    scroller = createScroller();

    configureScroller();

    configurePopup();

    installComboBoxListeners();

    installKeyboardActions();

  }

  /**

   * This method displays drow down list of combo box items on the screen.

   */

  public void show()

  {

    Dimension size = comboBox.getSize();

    size.height = getPopupHeightForRowCount(comboBox.getMaximumRowCount());

    Insets i = getInsets();

    size.width -= i.left + i.right;

    Rectangle bounds = computePopupBounds(0, comboBox.getBounds().height,

                                          size.width, size.height);

    scroller.setMaximumSize(bounds.getSize());

    scroller.setPreferredSize(bounds.getSize());

    scroller.setMinimumSize(bounds.getSize());

    list.invalidate();

    syncListSelection();

    list.ensureIndexIsVisible(list.getSelectedIndex());

    setLightWeightPopupEnabled(comboBox.isLightWeightPopupEnabled());

    show(comboBox, bounds.x, bounds.y);

  }

  /**

   * This method hides drop down list of items

   */

  public void hide()

  {

    MenuSelectionManager menuSelectionManager =

      MenuSelectionManager.defaultManager();

    javax.swing.MenuElement[] menuElements =

      menuSelectionManager.getSelectedPath();

    for (int i = 0; i < menuElements.length; i++)

      {

        if (menuElements[i] == this)

          {

            menuSelectionManager.clearSelectedPath();

            break;

          }

      }

    comboBox.repaint();

  }

  /**

   * Return list cointaining JComboBox's items

   *

   * @return list cointaining JComboBox's items

   */

  public JList getList()

  {

    return list;

  }

  /**

   * Returns MouseListener that is listening to mouse events occuring in the

   * combo box.

   *

   * @return MouseListener

   */

  public MouseListener getMouseListener()

  {

    return mouseListener;

  }

  /**

   * Returns MouseMotionListener that is listening to mouse  motion events

   * occuring in the combo box.

   *

   * @return MouseMotionListener

   */

  public MouseMotionListener getMouseMotionListener()

  {

    return mouseMotionListener;

  }

  /**

   * Returns KeyListener listening to key events occuring in the combo box.

   * This method returns null because KeyHandler is not longer used.

   *

   * @return KeyListener

   */

  public KeyListener getKeyListener()

  {

    return keyListener;

  }

  /**

   * This method uninstalls the UI for the  given JComponent.

   */

  public void uninstallingUI()

  {

    if (propertyChangeListener != null)

      {

        comboBox.removePropertyChangeListener(propertyChangeListener);

      }

    if (itemListener != null)

      {

        comboBox.removeItemListener(itemListener);

      }

    uninstallComboBoxModelListeners(comboBox.getModel());

    uninstallKeyboardActions();

    uninstallListListeners();

  }

  /**

   * This method uninstalls listeners that were listening to changes occuring

   * in the comb box's data model

   *

   * @param model data model for the combo box from which to uninstall

   *        listeners

   */

  protected void uninstallComboBoxModelListeners(ComboBoxModel model)

  {

    model.removeListDataListener(listDataListener);

  }

  /**

   * This method uninstalls keyboard actions installed by the UI.

   */

  protected void uninstallKeyboardActions()

  {

    // Nothing to do here.

  }

  /**

   * This method fires PopupMenuEvent indicating that combo box's popup list

   * of items will become visible

   */

  protected void firePopupMenuWillBecomeVisible()

  {

    PopupMenuListener[] ll = comboBox.getPopupMenuListeners();

    for (int i = 0; i < ll.length; i++)

      ll[i].popupMenuWillBecomeVisible(new PopupMenuEvent(comboBox));

  }

  /**

   * This method fires PopupMenuEvent indicating that combo box's popup list

   * of items will become invisible.

   */

  protected void firePopupMenuWillBecomeInvisible()

  {

    PopupMenuListener[] ll = comboBox.getPopupMenuListeners();

    for (int i = 0; i < ll.length; i++)

      ll[i].popupMenuWillBecomeInvisible(new PopupMenuEvent(comboBox));

  }

  /**

   * This method fires PopupMenuEvent indicating that combo box's popup list

   * of items was closed without selection.

   */

  protected void firePopupMenuCanceled()

  {

    PopupMenuListener[] ll = comboBox.getPopupMenuListeners();

    for (int i = 0; i < ll.length; i++)

      ll[i].popupMenuCanceled(new PopupMenuEvent(comboBox));

  }

  /**

   * Creates MouseListener to listen to mouse events occuring in the combo

   * box. Note that this listener doesn't listen to mouse events occuring in

   * the popup portion of the combo box, it only listens to main combo box

   * part.

   *

   * @return new MouseMotionListener that listens to mouse events occuring in

   *         the combo box

   */

  protected MouseListener createMouseListener()

  {

    return new InvocationMouseHandler();

  }

  /**

   * Create Mouse listener that listens to mouse dragging events occuring in

   * the combo box. This listener is responsible for changing the selection

   * in the combo box list to the component over which mouse is being

   * currently dragged

   *

   * @return new MouseMotionListener that listens to mouse dragging events

   *         occuring in the combo box

   */

  protected MouseMotionListener createMouseMotionListener()

  {

    return new InvocationMouseMotionHandler();

  }

  /**

   * KeyListener created in this method is not used anymore.

   *

   * @return KeyListener that does nothing

   */

  protected KeyListener createKeyListener()

  {

    return new InvocationKeyHandler();

  }

  /**

   * ListSelectionListener created in this method is not used anymore

   *

   * @return ListSelectionListener that does nothing

   */

  protected ListSelectionListener createListSelectionListener()

  {

    return new ListSelectionHandler();

  }

  /**

   * Creates ListDataListener. This method returns null, because

   * ListDataHandler class is obsolete and is no longer used.

   *

   * @return null

   */

  protected ListDataListener createListDataListener()

  {

    return null;

  }

  /**

   * This method creates ListMouseListener to listen to mouse events occuring

   * in the combo box's item list.

   *

   * @return MouseListener to listen to mouse events occuring in the combo

   *         box's items list.

   */

  protected MouseListener createListMouseListener()

  {

    return new ListMouseHandler();

  }

  /**

   * Creates ListMouseMotionlistener to listen to mouse motion events occuring

   * in the combo box's list. This listener is responsible for highlighting

   * items in the list when mouse is moved over them.

   *

   * @return MouseMotionListener that handles mouse motion events occuring in

   *         the list of the combo box.

   */

  protected MouseMotionListener createListMouseMotionListener()

  {

    return new ListMouseMotionHandler();

  }

  /**

   * Creates PropertyChangeListener to handle changes in the JComboBox's bound

   * properties.

   *

   * @return PropertyChangeListener to handle changes in the JComboBox's bound

   *         properties.

   */

  protected PropertyChangeListener createPropertyChangeListener()

  {

    return new PropertyChangeHandler();

  }

  /**

   * Creates new ItemListener that will listen to ItemEvents occuring in the

   * combo box.

   *

   * @return ItemListener to listen to ItemEvents occuring in the combo box.

   */

  protected ItemListener createItemListener()

  {

    return new ItemHandler();

  }

  /**

   * Creates JList that will be used to display items in the combo box.

   *

   * @return JList that will be used to display items in the combo box.

   */

  protected JList createList()

  {

    JList l = new JList(comboBox.getModel());

    return l;

  }

  /**

   * This method configures the list of comboBox's items by setting  default

   * properties and installing listeners.

   */

  protected void configureList()

  {

    list.setFont(comboBox.getFont());

    list.setForeground(comboBox.getForeground());

    list.setBackground(comboBox.getBackground());

    Color sfg = UIManager.getColor("ComboBox.selectionForeground");

    list.setSelectionForeground(sfg);

    Color sbg = UIManager.getColor("ComboBox.selectionBackground");

    list.setSelectionBackground(sbg);

    list.setBorder(null);

    list.setCellRenderer(comboBox.getRenderer());

    list.setFocusable(false);

    list.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);

    installListListeners();

  }

  /**

   * This method installs list listeners.

   */

  protected void installListListeners()

  {

    // mouse listener listening to mouse events occuring in the

    // combo box's list of items.

    listMouseListener = createListMouseListener();

    list.addMouseListener(listMouseListener);

    // mouse listener listening to mouse motion events occuring in the

    // combo box's list of items

    listMouseMotionListener = createListMouseMotionListener();

    list.addMouseMotionListener(listMouseMotionListener);

    listSelectionListener = createListSelectionListener();

    list.addListSelectionListener(listSelectionListener);

  }

  /**

   * This method creates scroll pane that will contain the list of comboBox's

   * items inside of it.

   *

   * @return JScrollPane

   */

  protected JScrollPane createScroller()

  {

    return new JScrollPane(list, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,

                           JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);

  }

  /**

   * This method configures scroll pane to contain list of comboBox's  items

   */

  protected void configureScroller()

  {

    scroller.setBorder(null);

    scroller.setFocusable(false);

    scroller.getVerticalScrollBar().setFocusable(false);

  }

  /**

   * This method configures popup menu that will be used to display Scrollpane

   * with list of items inside of it.

   */

  protected void configurePopup()

  {

    setBorderPainted(true);

    setBorder(BorderFactory.createLineBorder(Color.BLACK));

    setOpaque(false);

    add(scroller);

    setFocusable(false);

  }

  /*

   * This method installs listeners that will listen to changes occuring

   * in the combo box.

   */

  protected void installComboBoxListeners()

  {

    // item listener listenening to selection events in the combo box

    itemListener = createItemListener();

    comboBox.addItemListener(itemListener);

    propertyChangeListener = createPropertyChangeListener();

    comboBox.addPropertyChangeListener(propertyChangeListener);

    installComboBoxModelListeners(comboBox.getModel());

  }

  /**

   * This method installs listeners that will listen to changes occuring in

   * the comb box's data model

   *

   * @param model data model for the combo box for which to install listeners

   */

  protected void installComboBoxModelListeners(ComboBoxModel model)

  {

    // list data listener to listen for ListDataEvents in combo box.

    // This listener is now obsolete and nothing is done here

    listDataListener = createListDataListener();

    comboBox.getModel().addListDataListener(listDataListener);

  }

  /**

   * Installs the keyboard actions.

   */

  protected void installKeyboardActions()

  {

    // Nothing to do here

  }

  /**

   * This method always returns false to indicate that  items in the combo box

   * list are not focus traversable.

   *

   * @return false

   */

  public boolean isFocusTraversable()

  {

    return false;

  }

  /**

   * This method start scrolling combo box's list of items  either up or down

   * depending on the specified 'direction'

   *

   * @param direction of the scrolling.

   */

  protected void startAutoScrolling(int direction)

  {

    // FIXME: add timer

    isAutoScrolling = true;

    if (direction == SCROLL_UP)

      autoScrollUp();

    else

      autoScrollDown();

  }

  /**

   * This method stops scrolling the combo box's list of items

   */

  protected void stopAutoScrolling()

  {

    // FIXME: add timer

    isAutoScrolling = false;

  }

  /**

   * This method scrolls up list of combo box's items up and highlights that

   * just became visible.

   */

  protected void autoScrollUp()

  {

    // scroll up the scroll bar to make the item above visible

    JScrollBar scrollbar = scroller.getVerticalScrollBar();

    int scrollToNext = list.getScrollableUnitIncrement(super.getBounds(),

                                                       SwingConstants.VERTICAL,

                                                       SCROLL_UP);

    scrollbar.setValue(scrollbar.getValue() - scrollToNext);

    // If we haven't reached the begging of the combo box's list of items,

    // then highlight next element above currently highlighted element

    if (list.getSelectedIndex() != 0)

      list.setSelectedIndex(list.getSelectedIndex() - 1);

  }

  /**

   * This method scrolls down list of combo box's and highlights item in the

   * list that just became visible.

   */

  protected void autoScrollDown()

  {

    // scroll scrollbar down to make next item visible

    JScrollBar scrollbar = scroller.getVerticalScrollBar();

    int scrollToNext = list.getScrollableUnitIncrement(super.getBounds(),

                                                       SwingConstants.VERTICAL,

                                                       SCROLL_DOWN);

    scrollbar.setValue(scrollbar.getValue() + scrollToNext);

    // If we haven't reached the end of the combo box's list of items

    // then highlight next element below currently highlighted element

    if (list.getSelectedIndex() + 1 != comboBox.getItemCount())

      list.setSelectedIndex(list.getSelectedIndex() + 1);

  }

  /**

   * This method helps to delegate focus to the right component in the

   * JComboBox. If the comboBox is editable then focus is sent to

   * ComboBoxEditor, otherwise it is delegated to JComboBox.

   *

   * @param e MouseEvent

   */

  protected void delegateFocus(MouseEvent e)

  {

    if (comboBox.isEditable())

      comboBox.getEditor().getEditorComponent().requestFocus();

    else

      comboBox.requestFocus();

  }

  /**

   * This method displays combo box popup if the popup is  not currently shown

   * on the screen and hides it if it is  currently visible

   */

  protected void togglePopup()

  {

    if (isVisible())

      hide();

    else

      show();

  }

  /**

   * DOCUMENT ME!

   *

   * @param e DOCUMENT ME!

   *

   * @return DOCUMENT ME!

   */

  protected MouseEvent convertMouseEvent(MouseEvent e)

  {

    Point point = SwingUtilities.convertPoint((Component) e.getSource(),

                                              e.getPoint(), list);

    MouseEvent newEvent = new MouseEvent((Component) e.getSource(),

                                        e.getID(), e.getWhen(),

                                        e.getModifiers(), point.x, point.y,

                                        e.getModifiers(),

                                        e.isPopupTrigger());

    return newEvent;

  }

  /**

   * Returns required height of the popup such that number of items visible in

   * it are equal to the maximum row count.  By default

   * comboBox.maximumRowCount=8

   *

   * @param maxRowCount number of maximum visible rows in the  combo box's

   *        popup list of items

   *

   * @return height of the popup required to fit number of items  equal to

   *         JComboBox.maximumRowCount.

   */

  protected int getPopupHeightForRowCount(int maxRowCount)

  {

    int totalHeight = 0;

    ListCellRenderer rend = list.getCellRenderer();

    if (comboBox.getItemCount() < maxRowCount)

      maxRowCount = comboBox.getItemCount();

    for (int i = 0; i < maxRowCount; i++)

      {

        Component comp = rend.getListCellRendererComponent(list,

                                                           comboBox.getModel()

                                                                   .getElementAt(i),

                                                           -1, false, false);

        Dimension dim = comp.getPreferredSize();

        totalHeight += dim.height;

      }

    return totalHeight == 0 ? 100 : totalHeight;

  }

  /**

   * DOCUMENT ME!

   *

   * @param px DOCUMENT ME!

   * @param py DOCUMENT ME!

   * @param pw DOCUMENT ME!

   * @param ph DOCUMENT ME!

   *

   * @return DOCUMENT ME!

   */

  protected Rectangle computePopupBounds(int px, int py, int pw, int ph)

  {

    return new Rectangle(px, py, pw, ph);