- java.lang.Object
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- javax.swing.plaf.ComponentUI
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- javax.swing.plaf.ComboBoxUI
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- javax.swing.plaf.basic.BasicComboBoxUI
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- Direct Known Subclasses:
MetalComboBoxUI,SynthComboBoxUI
public class BasicComboBoxUI extends ComboBoxUI
Basic UI implementation for JComboBox.The combo box is a compound component which means that it is an aggregate of many simpler components. This class creates and manages the listeners on the combo box and the combo box model. These listeners update the user interface in response to changes in the properties and state 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 thecreatexxxListener()methods and supplying your own event listeners or subclassing from the ones supplied in this class.For adding specific actions, overide
installKeyboardActionsto add actions in response to KeyStroke bindings. See the article How to Use Key Bindings
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Nested Class Summary
Nested Classes Modifier and Type Class Description classBasicComboBoxUI.ComboBoxLayoutManagerThis layout manager handles the 'standard' layout of combo boxes.classBasicComboBoxUI.FocusHandlerThis listener hides the popup when the focus is lost.classBasicComboBoxUI.ItemHandlerThis listener watches for changes to the selection in the combo box.classBasicComboBoxUI.KeyHandlerThis listener checks to see if the key event isn't a navigation key.classBasicComboBoxUI.ListDataHandlerThis listener watches for changes in theComboBoxModel.classBasicComboBoxUI.PropertyChangeHandlerThis listener watches for bound properties that have changed in the combo box.
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Field Summary
Fields Modifier and Type Field Description protected JButtonarrowButtonThe arrow button that invokes the popup.protected DimensioncachedMinimumSizeThe cached minimum preferred size.protected JComboBox<Object>comboBoxThe instance ofJComboBox.protected CellRendererPanecurrentValuePaneUsed to render the currently selected item in the combo box.protected ComponenteditorThe Component that the @{code ComboBoxEditor} uses for editing.protected FocusListenerfocusListenerThis protected field is implementation specific.protected booleanhasFocusThis protected field is implementation specific.protected booleanisMinimumSizeDirtyThe flag for recalculating the minimum preferred size.protected ItemListeneritemListenerThis protected field is implementation specific.protected KeyListenerkeyListenerThis protected field is implementation specific.protected JList<Object>listBoxThis list is for drawing the current item in the combo box.protected ListDataListenerlistDataListenerThis protected field is implementation specific.protected InsetspaddingIf specified, these insets act as padding around the cell renderer when laying out and painting the "selected" item in the combo box.protected ComboPopuppopupThe implementation ofComboPopupthat is used to show the popup.protected KeyListenerpopupKeyListenerTheKeyListenerlistens to events.protected MouseListenerpopupMouseListenerTheMouseListenerlistens to events.protected MouseMotionListenerpopupMouseMotionListenerTheMouseMotionListenerlistens to events.protected PropertyChangeListenerpropertyChangeListenerThis protected field is implementation specific.protected booleansquareButtonIndicates whether or not the combo box button should be square.
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Constructor Summary
Constructors Constructor Description BasicComboBoxUI()
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description voidaddEditor()This public method is implementation specific and should be private.voidconfigureArrowButton()This public method is implementation specific and should be private.protected voidconfigureEditor()This protected method is implementation specific and should be private.protected JButtoncreateArrowButton()Creates a button which will be used as the control to show or hide the popup portion of the combo box.protected ComboBoxEditorcreateEditor()Creates the default editor that will be used in editable combo boxes.protected FocusListenercreateFocusListener()Creates aFocusListenerwhich will be added to the combo box.protected ItemListenercreateItemListener()Creates anItemListenerwhich will be added to the combo box.protected KeyListenercreateKeyListener()Creates aKeyListenerwhich will be added to the combo box.protected LayoutManagercreateLayoutManager()Creates a layout manager for managing the components which make up the combo box.protected ListDataListenercreateListDataListener()Creates a list data listener which will be added to theComboBoxModel.protected ComboPopupcreatePopup()Creates the popup portion of the combo box.protected PropertyChangeListenercreatePropertyChangeListener()Creates aPropertyChangeListenerwhich will be added to the combo box.protected ListCellRenderer<Object>createRenderer()Creates the default renderer that will be used in a non-editiable combo box.static ComponentUIcreateUI(JComponent c)Constructs a new instance ofBasicComboBoxUI.intgetBaseline(JComponent c, int width, int height)Returns the baseline.Component.BaselineResizeBehaviorgetBaselineResizeBehavior(JComponent c)Returns an enum indicating how the baseline of the component changes as the size changes.protected DimensiongetDefaultSize()Return the default size of an empty display area of the combo box using the current renderer and font.protected DimensiongetDisplaySize()Returns the calculated size of the display area.protected InsetsgetInsets()Gets the insets from the JComboBox.DimensiongetMinimumSize(JComponent c)The minimum size is the size of the display area plus insets plus the button.protected DimensiongetSizeForComponent(Component comp)Returns the size a component would have if used as a cell renderer.protected voidinstallComponents()Creates and initializes the components which make up the aggregate combo box.protected voidinstallDefaults()Installs the default colors, default font, default renderer, and default editor into the JComboBox.protected voidinstallKeyboardActions()Adds keyboard actions to the JComboBox.protected voidinstallListeners()Creates and installs listeners for the combo box and its model.booleanisFocusTraversable(JComboBox<?> c)Determines if the JComboBox is focus traversable.protected booleanisNavigationKey(int keyCode)Returns whether or not the supplied keyCode maps to a key that is used for navigation.booleanisPopupVisible(JComboBox<?> c)Tells if the popup is visible or not.voidpaintCurrentValue(Graphics g, Rectangle bounds, boolean hasFocus)Paints the currently selected item.voidpaintCurrentValueBackground(Graphics g, Rectangle bounds, boolean hasFocus)Paints the background of the currently selected item.protected RectanglerectangleForCurrentValue()Returns the area that is reserved for drawing the currently selected item.voidremoveEditor()This public method is implementation specific and should be private.protected voidselectNextPossibleValue()Selects the next item in the list.protected voidselectPreviousPossibleValue()Selects the previous item in the list.voidsetPopupVisible(JComboBox<?> c, boolean v)Hides the popup.protected voidtoggleOpenClose()Hides the popup if it is showing and shows the popup if it is hidden.voidunconfigureArrowButton()This public method is implementation specific and should be private.protected voidunconfigureEditor()This protected method is implementation specific and should be private.protected voiduninstallComponents()The aggregate components which comprise the combo box are unregistered and uninitialized.protected voiduninstallDefaults()Uninstalls the default colors, default font, default renderer, and default editor from the combo box.protected voiduninstallKeyboardActions()Removes the focus InputMap and ActionMap.protected voiduninstallListeners()Removes the installed listeners from the combo box and its model.-
Methods declared in class javax.swing.plaf.ComponentUI
contains, getAccessibleChild, getAccessibleChildrenCount, getMaximumSize, getPreferredSize, installUI, paint, uninstallUI, update
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Field Detail
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hasFocus
protected boolean hasFocus
This protected field is implementation specific. Do not access directly or override.
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currentValuePane
protected CellRendererPane currentValuePane
Used to render the currently selected item in the combo box. It doesn't have anything to do with the popup's rendering.
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popup
protected ComboPopup popup
The implementation ofComboPopupthat is used to show the popup.
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editor
protected Component editor
The Component that the @{code ComboBoxEditor} uses for editing.
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arrowButton
protected JButton arrowButton
The arrow button that invokes the popup.
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keyListener
protected KeyListener keyListener
This protected field is implementation specific. Do not access directly or override. Override the listener construction method instead.- See Also:
createKeyListener()
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focusListener
protected FocusListener focusListener
This protected field is implementation specific. Do not access directly or override. Override the listener construction method instead.- See Also:
createFocusListener()
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propertyChangeListener
protected PropertyChangeListener propertyChangeListener
This protected field is implementation specific. Do not access directly or override. Override the listener construction method instead.- See Also:
createPropertyChangeListener()
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itemListener
protected ItemListener itemListener
This protected field is implementation specific. Do not access directly or override. Override the listener construction method instead.- See Also:
createItemListener()
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popupMouseListener
protected MouseListener popupMouseListener
TheMouseListenerlistens to events.
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popupMouseMotionListener
protected MouseMotionListener popupMouseMotionListener
TheMouseMotionListenerlistens to events.
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popupKeyListener
protected KeyListener popupKeyListener
TheKeyListenerlistens to events.
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listDataListener
protected ListDataListener listDataListener
This protected field is implementation specific. Do not access directly or override. Override the listener construction method instead.- See Also:
createListDataListener()
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isMinimumSizeDirty
protected boolean isMinimumSizeDirty
The flag for recalculating the minimum preferred size.
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cachedMinimumSize
protected Dimension cachedMinimumSize
The cached minimum preferred size.
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squareButton
protected boolean squareButton
Indicates whether or not the combo box button should be square. If square, then the width and height are equal, and are both set to the height of the combo minus appropriate insets.- Since:
- 1.7
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padding
protected Insets padding
If specified, these insets act as padding around the cell renderer when laying out and painting the "selected" item in the combo box. These insets add to those specified by the cell renderer.- Since:
- 1.7
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Method Detail
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createUI
public static ComponentUI createUI(JComponent c)
Constructs a new instance ofBasicComboBoxUI.- Parameters:
c- a component- Returns:
- a new instance of
BasicComboBoxUI
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installDefaults
protected void installDefaults()
Installs the default colors, default font, default renderer, and default editor into the JComboBox.
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installListeners
protected void installListeners()
Creates and installs listeners for the combo box and its model. This method is called when the UI is installed.
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uninstallDefaults
protected void uninstallDefaults()
Uninstalls the default colors, default font, default renderer, and default editor from the combo box.
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uninstallListeners
protected void uninstallListeners()
Removes the installed listeners from the combo box and its model. The number and types of listeners removed and in this method should be the same that was added ininstallListeners
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createPopup
protected ComboPopup createPopup()
Creates the popup portion of the combo box.- Returns:
- an instance of
ComboPopup - See Also:
ComboPopup
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createKeyListener
protected KeyListener createKeyListener()
Creates aKeyListenerwhich 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
KeyListeneror null
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createFocusListener
protected FocusListener createFocusListener()
Creates aFocusListenerwhich 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
FocusListeneror null
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createListDataListener
protected ListDataListener createListDataListener()
Creates a list data listener which will be added to theComboBoxModel. If this method returns null then it will not be added to the combo box model.- Returns:
- an instance of a
ListDataListeneror null
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createItemListener
protected ItemListener createItemListener()
Creates anItemListenerwhich 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
ItemListeneror null
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createPropertyChangeListener
protected PropertyChangeListener createPropertyChangeListener()
Creates aPropertyChangeListenerwhich 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
PropertyChangeListeneror null
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createLayoutManager
protected LayoutManager createLayoutManager()
Creates a layout manager for managing the components which make up the combo box.- Returns:
- an instance of a layout manager
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createRenderer
protected ListCellRenderer<Object> createRenderer()
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 withsetRenderer.- Returns:
- a
ListCellRenderused for the combo box - See Also:
JComboBox.setRenderer(javax.swing.ListCellRenderer<? super E>)
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createEditor
protected ComboBoxEditor createEditor()
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 withsetEditor.- Returns:
- a
ComboBoxEditorused for the combo box - See Also:
JComboBox.setEditor(javax.swing.ComboBoxEditor)
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installComponents
protected void installComponents()
Creates and initializes the components which make up the aggregate combo box. This method is called as part of the UI installation process.
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uninstallComponents
protected void uninstallComponents()
The aggregate components which comprise the combo box are unregistered and uninitialized. This method is called as part of the UI uninstallation process.
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addEditor
public void addEditor()
This public method is implementation specific and should be private. do not call or override. To implement a specific editor create a customComboBoxEditor
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removeEditor
public void removeEditor()
This public method is implementation specific and should be private. do not call or override.- See Also:
addEditor()
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configureEditor
protected void configureEditor()
This protected method is implementation specific and should be private. do not call or override.- See Also:
addEditor()
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unconfigureEditor
protected void unconfigureEditor()
This protected method is implementation specific and should be private. Do not call or override.- See Also:
addEditor()
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configureArrowButton
public void configureArrowButton()
This public method is implementation specific and should be private. Do not call or override.- See Also:
createArrowButton()
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unconfigureArrowButton
public void unconfigureArrowButton()
This public method is implementation specific and should be private. Do not call or override.- See Also:
createArrowButton()
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createArrowButton
protected JButton createArrowButton()
Creates a button which will be used as the control to show or hide the popup portion of the combo box.- Returns:
- a button which represents the popup control
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isPopupVisible
public boolean isPopupVisible(JComboBox<?> c)
Tells if the popup is visible or not.- Specified by:
isPopupVisiblein classComboBoxUI- Parameters:
c- aJComboBox- Returns:
- true if popup of the
JComboBoxis visible
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setPopupVisible
public void setPopupVisible(JComboBox<?> c, boolean v)
Hides the popup.- Specified by:
setPopupVisiblein classComboBoxUI- Parameters:
c- aJComboBoxv- abooleandetermining the visibilty of the popup
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isFocusTraversable
public boolean isFocusTraversable(JComboBox<?> c)
Determines if the JComboBox is focus traversable. If the JComboBox is editable this returns false, otherwise it returns true.- Specified by:
isFocusTraversablein classComboBoxUI- Parameters:
c- aJComboBox- Returns:
- true if the given
JComboBoxis traversable
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getMinimumSize
public Dimension getMinimumSize(JComponent c)
The minimum size is the size of the display area plus insets plus the button.- Overrides:
getMinimumSizein classComponentUI- Parameters:
c- the component whose minimum size is being queried; this argument is often ignored, but might be used if the UI object is stateless and shared by multiple components- Returns:
- a
Dimensionobject ornull - See Also:
JComponent.getMinimumSize(),LayoutManager.minimumLayoutSize(java.awt.Container),ComponentUI.getPreferredSize(javax.swing.JComponent)
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getBaseline
public int getBaseline(JComponent c, int width, int height)
Returns the baseline.- Overrides:
getBaselinein classComponentUI- Parameters:
c-JComponentbaseline is being requested forwidth- the width to get the baseline forheight- the height to get the baseline for- Returns:
- baseline or a value < 0 indicating there is no reasonable baseline
- Throws:
NullPointerException- ifcisnullIllegalArgumentException- if width or height is < 0- Since:
- 1.6
- See Also:
JComponent.getBaseline(int, int)
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getBaselineResizeBehavior
public Component.BaselineResizeBehavior getBaselineResizeBehavior(JComponent c)
Returns an enum indicating how the baseline of the component changes as the size changes.- Overrides:
getBaselineResizeBehaviorin classComponentUI- Parameters:
c-JComponentto return baseline resize behavior for- Returns:
- an enum indicating how the baseline changes as the component size changes
- Throws:
NullPointerException- ifcisnull- Since:
- 1.6
- See Also:
JComponent.getBaseline(int, int)
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isNavigationKey
protected boolean isNavigationKey(int keyCode)
Returns whether or not the supplied keyCode maps to a key that is used for navigation. This is used for optimizing key input by only passing non- navigation keys to the type-ahead mechanism. Subclasses should override this if they change the navigation keys.- Parameters:
keyCode- a key code- Returns:
trueif the suppliedkeyCodemaps to a navigation key
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selectNextPossibleValue
protected void selectNextPossibleValue()
Selects the next item in the list. It won't change the selection if the currently selected item is already the last item.
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selectPreviousPossibleValue
protected void selectPreviousPossibleValue()
Selects the previous item in the list. It won't change the selection if the currently selected item is already the first item.
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toggleOpenClose
protected void toggleOpenClose()
Hides the popup if it is showing and shows the popup if it is hidden.
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rectangleForCurrentValue
protected Rectangle rectangleForCurrentValue()
Returns the area that is reserved for drawing the currently selected item.- Returns:
- the area that is reserved for drawing the currently selected item
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getInsets
protected Insets getInsets()
Gets the insets from the JComboBox.- Returns:
- the insets
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paintCurrentValue
public void paintCurrentValue(Graphics g, Rectangle bounds, boolean hasFocus)
Paints the currently selected item.- Parameters:
g- an instance ofGraphicsbounds- a bounding rectangle to render tohasFocus- is focused
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paintCurrentValueBackground
public void paintCurrentValueBackground(Graphics g, Rectangle bounds, boolean hasFocus)
Paints the background of the currently selected item.- Parameters:
g- an instance ofGraphicsbounds- a bounding rectangle to render tohasFocus- is focused
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getDefaultSize
protected Dimension getDefaultSize()
Return the default size of an empty display area of the combo box using the current renderer and font.- Returns:
- the size of an empty display area
- See Also:
getDisplaySize()
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getDisplaySize
protected Dimension getDisplaySize()
Returns the calculated size of the display area. The display area is the portion of the combo box in which the selected item is displayed. This method will use the prototype display value if it has been set.For combo boxes with a non trivial number of items, it is recommended to use a prototype display value to significantly speed up the display size calculation.
- Returns:
- the size of the display area calculated from the combo box items
- See Also:
JComboBox.setPrototypeDisplayValue(E)
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getSizeForComponent
protected Dimension getSizeForComponent(Component comp)
Returns the size a component would have if used as a cell renderer.- Parameters:
comp- aComponentto check- Returns:
- size of the component
- Since:
- 1.7
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installKeyboardActions
protected void installKeyboardActions()
Adds keyboard actions to the JComboBox. Actions on enter and esc are already supplied. Add more actions as you need them.
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uninstallKeyboardActions
protected void uninstallKeyboardActions()
Removes the focus InputMap and ActionMap.
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