Class BasicComboPopup

java.lang.Object
java.awt.Component
java.awt.Container
javax.swing.JComponent
javax.swing.JPopupMenu
javax.swing.plaf.basic.BasicComboPopup
All Implemented Interfaces:
ImageObserver, MenuContainer, Serializable, Accessible, MenuElement, ComboPopup
Direct Known Subclasses:
MetalComboBoxUI.MetalComboPopup
public class BasicComboPopup extends JPopupMenu implements ComboPopup
This is a basic implementation of the ComboPopup interface. This class represents the ui for the popup portion of the combo box.

All event handling is handled by listener classes created with the createxxxListener() methods and internal classes. You can change the behavior of this class by overriding the createxxxListener() methods and supplying your own event listeners or subclassing from the ones supplied in this class.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeans has been added to the java.beans package. Please see XMLEncoder.

Nested Class Summary

Modifier and Type Class Description
class  BasicComboPopup.InvocationKeyHandler
As of Java 2 platform v 1.4, this class is now obsolete and is only included for backwards API compatibility.
protected class  BasicComboPopup.InvocationMouseHandler
A listener to be registered upon the combo box (not its popup menu) to handle mouse events that affect the state of the popup menu.
protected class  BasicComboPopup.InvocationMouseMotionHandler
This listener watches for dragging and updates the current selection in the list if it is dragging over the list.
protected class  BasicComboPopup.ItemHandler
This listener watches for changes to the selection in the combo box.
class  BasicComboPopup.ListDataHandler
As of 1.4, this class is now obsolete, doesn't do anything, and is only included for backwards API compatibility.
protected class  BasicComboPopup.ListMouseHandler
This listener hides the popup when the mouse is released in the list.
protected class  BasicComboPopup.ListMouseMotionHandler
This listener changes the selected item as you move the mouse over the list.
protected class  BasicComboPopup.ListSelectionHandler
As of Java 2 platform v 1.4, this class is now obsolete, doesn't do anything, and is only included for backwards API compatibility.
protected class  BasicComboPopup.PropertyChangeHandler
This listener watches for bound properties that have changed in the combo box.

Nested classes/interfaces declared in class javax.swing.JPopupMenu

JPopupMenu.AccessibleJPopupMenu, JPopupMenu.Separator

Nested classes/interfaces declared in class javax.swing.JComponent

JComponent.AccessibleJComponent

Nested classes/interfaces declared in class java.awt.Container

Container.AccessibleAWTContainer

Nested classes/interfaces declared in class java.awt.Component

Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy

Field Summary

Modifier and Type Field Description
protected Timer autoscrollTimer
This protected field is implementation specific.
protected JComboBox<Object> comboBox
The instance of JComboBox.
protected boolean hasEntered
true if the mouse cursor is in the popup.
protected boolean isAutoScrolling
If true the auto-scrolling is enabled.
protected ItemListener itemListener
This protected field is implementation specific.
protected KeyListener keyListener
This protected field is implementation specific.
protected JList<Object> list
This protected field is implementation specific.
protected ListDataListener listDataListener
This protected field is implementation specific.
protected MouseListener listMouseListener
This protected field is implementation specific.
protected MouseMotionListener listMouseMotionListener
This protected field is implementation specific.
protected ListSelectionListener listSelectionListener
This protected field is implementation specific.
protected MouseListener mouseListener
This protected field is implementation specific.
protected MouseMotionListener mouseMotionListener
This protected field is implementation specific.
protected PropertyChangeListener propertyChangeListener
This protected field is implementation specific.
protected static final int SCROLL_DOWN
The direction of scrolling down.
protected static final int SCROLL_UP
The direction of scrolling up.
protected int scrollDirection
The direction of scrolling.
protected JScrollPane scroller
This protected field is implementation specific.
protected boolean valueIsAdjusting
As of Java 2 platform v1.4 this previously undocumented field is no longer used.

Fields declared in class javax.swing.JComponent

listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW

Fields declared in class java.awt.Component

accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields declared in interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

Constructor Description
BasicComboPopup(JComboBox<Object> combo)
Constructs a new instance of BasicComboPopup.

Method Summary

Modifier and Type Method Description
protected void autoScrollDown()
This protected method is implementation specific and should be private.
protected void autoScrollUp()
This protected method is implementation specific and should be private.
protected Rectangle computePopupBounds(int px, int py, int pw, int ph)
Calculate the placement and size of the popup portion of the combo box based on the combo box location and the enclosing screen bounds.
protected void configureList()
Configures the list which is used to hold the combo box items in the popup.
protected void configurePopup()
Configures the popup portion of the combo box.
protected void configureScroller()
Configures the scrollable portion which holds the list within the combo box popup.
protected MouseEvent convertMouseEvent(MouseEvent e)
Converts mouse event.
protected ItemListener createItemListener()
Creates an ItemListener which will be added to the combo box.
protected KeyListener createKeyListener()
Creates the key listener that will be added to the combo box.
protected JList<Object> createList()
Creates the JList used in the popup to display the items in the combo box model.
protected ListDataListener createListDataListener()
Creates a list data listener which will be added to the ComboBoxModel.
protected MouseListener createListMouseListener()
Creates a mouse listener that watches for mouse events in the popup's list.
protected MouseMotionListener createListMouseMotionListener()
Creates a mouse motion listener that watches for mouse motion events in the popup's list.
protected ListSelectionListener createListSelectionListener()
Creates a list selection listener that watches for selection changes in the popup's list.
protected MouseListener createMouseListener()
Creates a listener that will watch for mouse-press and release events on the combo box.
protected MouseMotionListener createMouseMotionListener()
Creates the mouse motion listener which will be added to the combo box.
protected PropertyChangeListener createPropertyChangeListener()
Creates a PropertyChangeListener which will be added to the combo box.
protected JScrollPane createScroller()
Creates the scroll pane which houses the scrollable list.
protected void delegateFocus(MouseEvent e)
This is a utility method that helps event handlers figure out where to send the focus when the popup is brought up.
AccessibleContext getAccessibleContext()
Gets the AccessibleContext associated with this BasicComboPopup.
KeyListener getKeyListener()
Implementation of ComboPopup.getKeyListener().
JList<Object> getList()
Implementation of ComboPopup.getList().
MouseListener getMouseListener()
Implementation of ComboPopup.getMouseListener().
MouseMotionListener getMouseMotionListener()
Implementation of ComboPopup.getMouseMotionListener().
protected int getPopupHeightForRowCount(int maxRowCount)
Retrieves the height of the popup based on the current ListCellRenderer and the maximum row count.
void hide()
Implementation of ComboPopup.hide().
protected void installComboBoxListeners()
This method adds the necessary listeners to the JComboBox.
protected void installComboBoxModelListeners(ComboBoxModel<?> model)
Installs the listeners on the combo box model.
protected void installKeyboardActions()
Registers keyboard actions.
protected void installListListeners()
Adds the listeners to the list control.
boolean isFocusTraversable()
Overridden to unconditionally return false.
void show()
Implementation of ComboPopup.show().
protected void startAutoScrolling(int direction)
This protected method is implementation specific and should be private.
protected void stopAutoScrolling()
This protected method is implementation specific and should be private.
protected void togglePopup()
Makes the popup visible if it is hidden and makes it hidden if it is visible.
protected void uninstallComboBoxModelListeners(ComboBoxModel<?> model)
Removes the listeners from the combo box model
void uninstallingUI()
Called when the UI is uninstalling.
protected void uninstallKeyboardActions()
Unregisters keyboard actions.
protected void updateListBoxSelectionForEvent(MouseEvent anEvent, boolean shouldScroll)
A utility method used by the event listeners.

Methods declared in class javax.swing.JPopupMenu

add, add, add, addMenuKeyListener, addPopupMenuListener, addSeparator, createActionChangeListener, createActionComponent, firePopupMenuCanceled, firePopupMenuWillBecomeInvisible, firePopupMenuWillBecomeVisible, getComponent, getComponentAtIndex, getComponentIndex, getDefaultLightWeightPopupEnabled, getInvoker, getLabel, getMargin, getMenuKeyListeners, getPopupMenuListeners, getSelectionModel, getSubElements, getUI, getUIClassID, insert, insert, isBorderPainted, isLightWeightPopupEnabled, isPopupTrigger, isVisible, menuSelectionChanged, pack, paintBorder, paramString, processKeyEvent, processKeyEvent, processMouseEvent, remove, removeMenuKeyListener, removePopupMenuListener, setBorderPainted, setDefaultLightWeightPopupEnabled, setInvoker, setLabel, setLightWeightPopupEnabled, setLocation, setPopupSize, setPopupSize, setSelected, setSelectionModel, setUI, setVisible, show, updateUI

Methods declared in class javax.swing.JComponent

addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeNotify, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setEnabled, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, unregisterKeyboardAction, update

Methods declared in class java.awt.Container

add, add, add, add, add, addContainerListener, addImpl, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusDownCycle, validate, validateTree

Methods declared in class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setMixingCutoutShape, setName, setSize, setSize, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods declared in interface javax.swing.plaf.basic.ComboPopup

isVisible

Field Details

comboBox

protected JComboBox<Object> comboBox
The instance of JComboBox.

list

protected JList<Object> list
This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
See Also:

scroller

protected JScrollPane scroller
This protected field is implementation specific. Do not access directly or override. Use the create method instead
See Also:

valueIsAdjusting

protected boolean valueIsAdjusting
As of Java 2 platform v1.4 this previously undocumented field is no longer used.

mouseMotionListener

protected MouseMotionListener mouseMotionListener
This protected field is implementation specific. Do not access directly or override. Use the accessor or create methods instead.
See Also:

mouseListener

protected MouseListener mouseListener
This protected field is implementation specific. Do not access directly or override. Use the accessor or create methods instead.
See Also:

keyListener

protected KeyListener keyListener
This protected field is implementation specific. Do not access directly or override. Use the accessor or create methods instead.
See Also:

listSelectionListener

protected ListSelectionListener listSelectionListener
This protected field is implementation specific. Do not access directly or override. Use the create method instead.
See Also:

listMouseListener

protected MouseListener listMouseListener
This protected field is implementation specific. Do not access directly or override. Use the create method instead.
See Also:

listMouseMotionListener

protected MouseMotionListener listMouseMotionListener
This protected field is implementation specific. Do not access directly or override. Use the create method instead
See Also:

propertyChangeListener

protected PropertyChangeListener propertyChangeListener
This protected field is implementation specific. Do not access directly or override. Use the create method instead
See Also:

listDataListener

protected ListDataListener listDataListener
This protected field is implementation specific. Do not access directly or override. Use the create method instead
See Also:

itemListener

protected ItemListener itemListener
This protected field is implementation specific. Do not access directly or override. Use the create method instead
See Also:

autoscrollTimer

protected Timer autoscrollTimer
This protected field is implementation specific. Do not access directly or override.

hasEntered

protected boolean hasEntered
true if the mouse cursor is in the popup.

isAutoScrolling

protected boolean isAutoScrolling
If true the auto-scrolling is enabled.

scrollDirection

protected int scrollDirection
The direction of scrolling.

SCROLL_UP

protected static final int SCROLL_UP
The direction of scrolling up.
See Also:

SCROLL_DOWN

protected static final int SCROLL_DOWN
The direction of scrolling down.
See Also:

Constructor Details

BasicComboPopup

public BasicComboPopup(JComboBox<Object> combo)
Constructs a new instance of BasicComboPopup.
Parameters:
combo - an instance of JComboBox

Method Details

show

public void show()
Implementation of ComboPopup.show().
Specified by:
show in interface ComboPopup
Overrides:
show in class Component

hide

public void hide()
Implementation of ComboPopup.hide().
Specified by:
hide in interface ComboPopup
Overrides:
hide in class JComponent

getList

public JList<Object> getList()
Implementation of ComboPopup.getList().
Specified by:
getList in interface ComboPopup
Returns:
the list that is being used to draw the items in the combo box

getMouseListener

public MouseListener getMouseListener()
Implementation of ComboPopup.getMouseListener().
Specified by:
getMouseListener in interface ComboPopup
Returns:
a MouseListener or null
See Also:

getMouseMotionListener

public MouseMotionListener getMouseMotionListener()
Implementation of ComboPopup.getMouseMotionListener().
Specified by:
getMouseMotionListener in interface ComboPopup
Returns:
a MouseMotionListener or null
See Also:

getKeyListener

public KeyListener getKeyListener()
Implementation of ComboPopup.getKeyListener().
Specified by:
getKeyListener in interface ComboPopup
Returns:
a KeyListener or null
See Also:

uninstallingUI

public void uninstallingUI()
Called when the UI is uninstalling. Since this popup isn't in the component tree, it won't get it's uninstallUI() called. It removes the listeners that were added in addComboBoxListeners().
Specified by:
uninstallingUI in interface ComboPopup

uninstallComboBoxModelListeners

protected void uninstallComboBoxModelListeners(ComboBoxModel<?> model)
Removes the listeners from the combo box model
Parameters:
model - The combo box model to install listeners
See Also:

uninstallKeyboardActions

protected void uninstallKeyboardActions()
Unregisters keyboard actions.

createMouseListener

protected MouseListener createMouseListener()
Creates a listener that will watch for mouse-press and release events on the combo box. Warning: When overriding this method, make sure to maintain the existing behavior.
Returns:
a MouseListener which will be added to the combo box or null

createMouseMotionListener

protected MouseMotionListener createMouseMotionListener()
Creates the mouse motion listener which will be added to the combo box. Warning: When overriding this method, make sure to maintain the existing behavior.
Returns:
a MouseMotionListener which will be added to the combo box or null

createKeyListener

protected KeyListener createKeyListener()
Creates the key listener that will be added to the combo box. If this method returns null then it will not be added to the combo box.
Returns:
a KeyListener or null

createListSelectionListener

protected ListSelectionListener createListSelectionListener()
Creates a list selection listener that watches for selection changes in the popup's list. If this method returns null then it will not be added to the popup list.
Returns:
an instance of a ListSelectionListener or null

createListDataListener

protected ListDataListener createListDataListener()
Creates a list data listener which will be added to the ComboBoxModel. If this method returns null then it will not be added to the combo box model.
Returns:
an instance of a ListDataListener or null

createListMouseListener

protected MouseListener createListMouseListener()
Creates a mouse listener that watches for mouse events in the popup's list. If this method returns null then it will not be added to the combo box.
Returns:
an instance of a MouseListener or null

createListMouseMotionListener

protected MouseMotionListener createListMouseMotionListener()
Creates a mouse motion listener that watches for mouse motion events in the popup's list. If this method returns null then it will not be added to the combo box.
Returns:
an instance of a MouseMotionListener or null

createPropertyChangeListener

protected PropertyChangeListener createPropertyChangeListener()
Creates a PropertyChangeListener which will be added to the combo box. If this method returns null then it will not be added to the combo box.
Returns:
an instance of a PropertyChangeListener or null

createItemListener

protected ItemListener createItemListener()
Creates an ItemListener which will be added to the combo box. If this method returns null then it will not be added to the combo box.

Subclasses may override this method to return instances of their own ItemEvent handlers.

Returns:
an instance of an ItemListener or null

createList

protected JList<Object> createList()
Creates the JList used in the popup to display the items in the combo box model. This method is called when the UI class is created.
Returns:
a JList used to display the combo box items

configureList

protected void configureList()
Configures the list which is used to hold the combo box items in the popup. This method is called when the UI class is created.
See Also:

installListListeners

protected void installListListeners()
Adds the listeners to the list control.

createScroller

protected JScrollPane createScroller()
Creates the scroll pane which houses the scrollable list.
Returns:
the scroll pane which houses the scrollable list

configureScroller

protected void configureScroller()
Configures the scrollable portion which holds the list within the combo box popup. This method is called when the UI class is created.

configurePopup

protected void configurePopup()
Configures the popup portion of the combo box. This method is called when the UI class is created.

installComboBoxListeners

protected void installComboBoxListeners()
This method adds the necessary listeners to the JComboBox.

installComboBoxModelListeners

protected void installComboBoxModelListeners(ComboBoxModel<?> model)
Installs the listeners on the combo box model. Any listeners installed on the combo box model should be removed in uninstallComboBoxModelListeners.
Parameters:
model - The combo box model to install listeners
See Also:

installKeyboardActions

protected void installKeyboardActions()
Registers keyboard actions.

isFocusTraversable

public boolean isFocusTraversable()
Overridden to unconditionally return false.
Overrides:
isFocusTraversable in class Component
Returns:
true if this Component is focusable; false otherwise
See Also:

startAutoScrolling

protected void startAutoScrolling(int direction)
This protected method is implementation specific and should be private. do not call or override.
Parameters:
direction - the direction of scrolling

stopAutoScrolling

protected void stopAutoScrolling()
This protected method is implementation specific and should be private. do not call or override.

autoScrollUp

protected void autoScrollUp()
This protected method is implementation specific and should be private. do not call or override.

autoScrollDown

protected void autoScrollDown()
This protected method is implementation specific and should be private. do not call or override.

getAccessibleContext

public AccessibleContext getAccessibleContext()
Gets the AccessibleContext associated with this BasicComboPopup. The AccessibleContext will have its parent set to the ComboBox.
Specified by:
getAccessibleContext in interface Accessible
Overrides:
getAccessibleContext in class JPopupMenu
Returns:
an AccessibleContext for the BasicComboPopup
Since:
1.5

delegateFocus

protected void delegateFocus(MouseEvent e)
This is a utility method that helps event handlers figure out where to send the focus when the popup is brought up. The standard implementation delegates the focus to the editor (if the combo box is editable) or to the JComboBox if it is not editable.
Parameters:
e - a mouse event

togglePopup

protected void togglePopup()
Makes the popup visible if it is hidden and makes it hidden if it is visible.

convertMouseEvent

protected MouseEvent convertMouseEvent(MouseEvent e)
Converts mouse event.
Parameters:
e - a mouse event
Returns:
converted mouse event

getPopupHeightForRowCount

protected int getPopupHeightForRowCount(int maxRowCount)
Retrieves the height of the popup based on the current ListCellRenderer and the maximum row count.
Parameters:
maxRowCount - the row count
Returns:
the height of the popup

computePopupBounds

protected Rectangle computePopupBounds(int px, int py, int pw, int ph)
Calculate the placement and size of the popup portion of the combo box based on the combo box location and the enclosing screen bounds. If no transformations are required, then the returned rectangle will have the same values as the parameters.
Parameters:
px - starting x location
py - starting y location
pw - starting width
ph - starting height
Returns:
a rectangle which represents the placement and size of the popup

updateListBoxSelectionForEvent

protected void updateListBoxSelectionForEvent(MouseEvent anEvent, boolean shouldScroll)
A utility method used by the event listeners. Given a mouse event, it changes the list selection to the list item below the mouse.
Parameters:
anEvent - a mouse event
shouldScroll - if true list should be scrolled.

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/17/docs/api/java.desktop/javax/swing/plaf/basic/BasicComboPopup.html