- java.lang.Object
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- java.awt.Component
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- java.awt.Container
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- javax.swing.JComponent
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- javax.swing.JComboBox<E>
 
 
 
 
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- Type Parameters:
- E- the type of the elements of this combo box
 - All Implemented Interfaces:
- ActionListener,- ImageObserver,- ItemSelectable,- MenuContainer,- Serializable,- EventListener,- Accessible,- ListDataListener
 
 @JavaBean(defaultProperty="UI", description="A combination of a text field and a drop-down list.") public class JComboBox<E> extends JComponent implements ItemSelectable, ListDataListener, ActionListener, Accessible A component that combines a button or editable field and a drop-down list. The user can select a value from the drop-down list, which appears at the user's request. If you make the combo box editable, then the combo box includes an editable field into which the user can type a value.Warning: Swing is not thread safe. For more information see Swing's Threading Policy. 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.beanspackage. Please seeXMLEncoder.See How to Use Combo Boxes in The Java Tutorial for further information. - Since:
- 1.2
- See Also:
- ComboBoxModel,- DefaultComboBoxModel, Serialized Form
 
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Nested Class SummaryNested Classes Modifier and Type Class Description protected classJComboBox.AccessibleJComboBoxThis class implements accessibility support for theJComboBoxclass.static interfaceJComboBox.KeySelectionManagerThe interface that defines aKeySelectionManager.- 
Nested classes/interfaces declared in class javax.swing.JComponentJComponent.AccessibleJComponent
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Nested classes/interfaces declared in class java.awt.ContainerContainer.AccessibleAWTContainer
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Nested classes/interfaces declared in class java.awt.ComponentComponent.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy
 
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Field SummaryFields Modifier and Type Field Description protected StringactionCommandThis protected field is implementation specific.protected ComboBoxModel<E>dataModelThis protected field is implementation specific.protected ComboBoxEditoreditorThis protected field is implementation specific.protected booleanisEditableThis protected field is implementation specific.protected JComboBox.KeySelectionManagerkeySelectionManagerThis protected field is implementation specific.protected booleanlightWeightPopupEnabledThis protected field is implementation specific.protected intmaximumRowCountThis protected field is implementation specific.protected ListCellRenderer<? super E>rendererThis protected field is implementation specific.protected ObjectselectedItemReminderThis protected field is implementation specific.- 
Fields declared in class javax.swing.JComponentlistenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW
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Fields declared in class java.awt.ComponentaccessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT
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Fields declared in interface java.awt.image.ImageObserverABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH
 
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Constructor SummaryConstructors Constructor Description JComboBox()Creates aJComboBoxwith a default data model.JComboBox(E[] items)Creates aJComboBoxthat contains the elements in the specified array.JComboBox(Vector<E> items)Creates aJComboBoxthat contains the elements in the specified Vector.JComboBox(ComboBoxModel<E> aModel)Creates aJComboBoxthat takes its items from an existingComboBoxModel.
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Method SummaryAll Methods Instance Methods Concrete Methods Modifier and Type Method Description voidactionPerformed(ActionEvent e)This method is public as an implementation side effect.protected voidactionPropertyChanged(Action action, String propertyName)Updates the combobox's state in response to property changes in associated action.voidaddActionListener(ActionListener l)Adds anActionListener.voidaddItem(E item)Adds an item to the item list.voidaddItemListener(ItemListener aListener)Adds anItemListener.voidaddPopupMenuListener(PopupMenuListener l)Adds aPopupMenulistener which will listen to notification messages from the popup portion of the combo box.voidconfigureEditor(ComboBoxEditor anEditor, Object anItem)Initializes the editor with the specified item.protected voidconfigurePropertiesFromAction(Action a)Sets the properties on this combobox to match those in the specifiedAction.voidcontentsChanged(ListDataEvent e)This method is public as an implementation side effect.protected PropertyChangeListenercreateActionPropertyChangeListener(Action a)Creates and returns aPropertyChangeListenerthat is responsible for listening for changes from the specifiedActionand updating the appropriate properties.protected JComboBox.KeySelectionManagercreateDefaultKeySelectionManager()Returns an instance of the default key-selection manager.protected voidfireActionEvent()Notifies all listeners that have registered interest for notification on this event type.protected voidfireItemStateChanged(ItemEvent e)Notifies all listeners that have registered interest for notification on this event type.voidfirePopupMenuCanceled()NotifiesPopupMenuListeners that the popup portion of the combo box has been canceled.voidfirePopupMenuWillBecomeInvisible()NotifiesPopupMenuListeners that the popup portion of the combo box has become invisible.voidfirePopupMenuWillBecomeVisible()NotifiesPopupMenuListeners that the popup portion of the combo box will become visible.AccessibleContextgetAccessibleContext()Gets the AccessibleContext associated with this JComboBox.ActiongetAction()Returns the currently setActionfor thisActionEventsource, ornullif noActionis set.StringgetActionCommand()Returns the action command that is included in the event sent to action listeners.ActionListener[]getActionListeners()Returns an array of all theActionListeners added to this JComboBox with addActionListener().ComboBoxEditorgetEditor()Returns the editor used to paint and edit the selected item in theJComboBoxfield.EgetItemAt(int index)Returns the list item at the specified index.intgetItemCount()Returns the number of items in the list.ItemListener[]getItemListeners()Returns an array of all theItemListeners added to this JComboBox with addItemListener().JComboBox.KeySelectionManagergetKeySelectionManager()Returns the list's key-selection manager.intgetMaximumRowCount()Returns the maximum number of items the combo box can display without a scrollbarComboBoxModel<E>getModel()Returns the data model currently used by theJComboBox.PopupMenuListener[]getPopupMenuListeners()Returns an array of all thePopupMenuListeners added to this JComboBox with addPopupMenuListener().EgetPrototypeDisplayValue()Returns the "prototypical display" value - an Object used for the calculation of the display height and width.ListCellRenderer<? super E>getRenderer()Returns the renderer used to display the selected item in theJComboBoxfield.intgetSelectedIndex()Returns the first item in the list that matches the given item.ObjectgetSelectedItem()Returns the current selected item.Object[]getSelectedObjects()Returns an array containing the selected item.ComboBoxUIgetUI()Returns the L&F object that renders this component.StringgetUIClassID()Returns the name of the L&F class that renders this component.voidhidePopup()Causes the combo box to close its popup window.voidinsertItemAt(E item, int index)Inserts an item into the item list at a given index.protected voidinstallAncestorListener()Registers ancestor listener so that it will receiveAncestorEventswhen it or any of its ancestors move or are made visible or invisible.voidintervalAdded(ListDataEvent e)This method is public as an implementation side effect.voidintervalRemoved(ListDataEvent e)This method is public as an implementation side effect.booleanisEditable()Returns true if theJComboBoxis editable.booleanisLightWeightPopupEnabled()Gets the value of thelightWeightPopupEnabledproperty.booleanisPopupVisible()Determines the visibility of the popup.protected StringparamString()Returns a string representation of thisJComboBox.voidprocessKeyEvent(KeyEvent e)HandlesKeyEvents, looking for the Tab key.voidremoveActionListener(ActionListener l)Removes anActionListener.voidremoveAllItems()Removes all items from the item list.voidremoveItem(Object anObject)Removes an item from the item list.voidremoveItemAt(int anIndex)Removes the item atanIndexThis method works only if theJComboBoxuses a mutable data model.voidremoveItemListener(ItemListener aListener)Removes anItemListener.voidremovePopupMenuListener(PopupMenuListener l)Removes aPopupMenuListener.protected voidselectedItemChanged()This protected method is implementation specific.booleanselectWithKeyChar(char keyChar)Selects the list item that corresponds to the specified keyboard character and returns true, if there is an item corresponding to that character.voidsetAction(Action a)Sets theActionfor theActionEventsource.voidsetActionCommand(String aCommand)Sets the action command that should be included in the event sent to action listeners.voidsetEditable(boolean aFlag)Determines whether theJComboBoxfield is editable.voidsetEditor(ComboBoxEditor anEditor)Sets the editor used to paint and edit the selected item in theJComboBoxfield.voidsetEnabled(boolean b)Enables the combo box so that items can be selected.voidsetKeySelectionManager(JComboBox.KeySelectionManager aManager)Sets the object that translates a keyboard character into a list selection.voidsetLightWeightPopupEnabled(boolean aFlag)Sets thelightWeightPopupEnabledproperty, which provides a hint as to whether or not a lightweightComponentshould be used to contain theJComboBox, versus a heavyweightComponentsuch as aPanelor aWindow.voidsetMaximumRowCount(int count)Sets the maximum number of rows theJComboBoxdisplays.voidsetModel(ComboBoxModel<E> aModel)Sets the data model that theJComboBoxuses to obtain the list of items.voidsetPopupVisible(boolean v)Sets the visibility of the popup.voidsetPrototypeDisplayValue(E prototypeDisplayValue)Sets the prototype display value used to calculate the size of the display for the UI portion.voidsetRenderer(ListCellRenderer<? super E> aRenderer)Sets the renderer that paints the list items and the item selected from the list in the JComboBox field.voidsetSelectedIndex(int anIndex)Selects the item at indexanIndex.voidsetSelectedItem(Object anObject)Sets the selected item in the combo box display area to the object in the argument.voidsetUI(ComboBoxUI ui)Sets the L&F object that renders this component.voidshowPopup()Causes the combo box to display its popup window.voidupdateUI()Resets the UI property to a value from the current look and feel.- 
Methods declared in class javax.swing.JComponentaddAncestorListener, 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, paintBorder, 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, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update
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Methods declared in class java.awt.Containeradd, 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, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, setLayout, transferFocusDownCycle, validate, validateTree
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Methods declared in class java.awt.Componentaction, 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, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, 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, setLocation, setMixingCutoutShape, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle
 
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Field Detail- 
dataModelprotected ComboBoxModel<E> dataModel This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.- See Also:
- getModel(),- setModel(javax.swing.ComboBoxModel<E>)
 
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rendererprotected ListCellRenderer<? super E> renderer This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
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editorprotected ComboBoxEditor editor This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.- See Also:
- getEditor(),- setEditor(javax.swing.ComboBoxEditor)
 
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maximumRowCountprotected int maximumRowCount This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.- See Also:
- getMaximumRowCount(),- setMaximumRowCount(int)
 
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isEditableprotected boolean isEditable This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.- See Also:
- isEditable,- setEditable(boolean)
 
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keySelectionManagerprotected JComboBox.KeySelectionManager keySelectionManager This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
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actionCommandprotected String actionCommand This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
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lightWeightPopupEnabledprotected boolean lightWeightPopupEnabled This protected field is implementation specific. Do not access directly or override. Use the accessor methods instead.
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selectedItemReminderprotected Object selectedItemReminder This protected field is implementation specific. Do not access directly or override.
 
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Constructor Detail- 
JComboBoxpublic JComboBox(ComboBoxModel<E> aModel) Creates aJComboBoxthat takes its items from an existingComboBoxModel. Since theComboBoxModelis provided, a combo box created using this constructor does not create a default combo box model and may impact how the insert, remove and add methods behave.- Parameters:
- aModel- the- ComboBoxModelthat provides the displayed list of items
- See Also:
- DefaultComboBoxModel
 
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JComboBoxpublic JComboBox(E[] items) Creates aJComboBoxthat contains the elements in the specified array. By default the first item in the array (and therefore the data model) becomes selected.- Parameters:
- items- an array of objects to insert into the combo box
- See Also:
- DefaultComboBoxModel
 
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JComboBoxpublic JComboBox(Vector<E> items) Creates aJComboBoxthat contains the elements in the specified Vector. By default the first item in the vector (and therefore the data model) becomes selected.- Parameters:
- items- an array of vectors to insert into the combo box
- See Also:
- DefaultComboBoxModel
 
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JComboBoxpublic JComboBox() Creates aJComboBoxwith a default data model. The default data model is an empty list of objects. UseaddItemto add items. By default the first item in the data model becomes selected.- See Also:
- DefaultComboBoxModel
 
 
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Method Detail- 
installAncestorListenerprotected void installAncestorListener() Registers ancestor listener so that it will receiveAncestorEventswhen it or any of its ancestors move or are made visible or invisible. Events are also sent when the component or its ancestors are added or removed from the containment hierarchy.
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setUI@BeanProperty(hidden=true, visualUpdate=true, description="The UI object that implements the Component\'s LookAndFeel.") public void setUI(ComboBoxUI ui) Sets the L&F object that renders this component.- Parameters:
- ui- the- ComboBoxUIL&F object
- See Also:
- UIDefaults.getUI(javax.swing.JComponent)
 
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updateUIpublic void updateUI() Resets the UI property to a value from the current look and feel.- Overrides:
- updateUIin class- JComponent
- See Also:
- JComponent.updateUI()
 
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getUIClassID@BeanProperty(bound=false) public String getUIClassID() Returns the name of the L&F class that renders this component.- Overrides:
- getUIClassIDin class- JComponent
- Returns:
- the string "ComboBoxUI"
- See Also:
- JComponent.getUIClassID(),- UIDefaults.getUI(javax.swing.JComponent)
 
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getUIpublic ComboBoxUI getUI() Returns the L&F object that renders this component.- Overrides:
- getUIin class- JComponent
- Returns:
- the ComboBoxUI object that renders this component
 
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setModel@BeanProperty(description="Model that the combo box uses to get data to display.") public void setModel(ComboBoxModel<E> aModel) Sets the data model that theJComboBoxuses to obtain the list of items.- Parameters:
- aModel- the- ComboBoxModelthat provides the displayed list of items
 
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getModelpublic ComboBoxModel<E> getModel() Returns the data model currently used by theJComboBox.- Returns:
- the ComboBoxModelthat provides the displayed list of items
 
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setLightWeightPopupEnabled@BeanProperty(expert=true, description="Set to <code>false</code> to require heavyweight popups.") public void setLightWeightPopupEnabled(boolean aFlag) Sets thelightWeightPopupEnabledproperty, which provides a hint as to whether or not a lightweightComponentshould be used to contain theJComboBox, versus a heavyweightComponentsuch as aPanelor aWindow. The decision of lightweight versus heavyweight is ultimately up to theJComboBox. Lightweight windows are more efficient than heavyweight windows, but lightweight and heavyweight components do not mix well in a GUI. If your application mixes lightweight and heavyweight components, you should disable lightweight popups. The default value for thelightWeightPopupEnabledproperty istrue, unless otherwise specified by the look and feel. Some look and feels always use heavyweight popups, no matter what the value of this property.See the article Mixing Heavy and Light Components This method fires a property changed event. - Parameters:
- aFlag- if- true, lightweight popups are desired
 
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isLightWeightPopupEnabledpublic boolean isLightWeightPopupEnabled() Gets the value of thelightWeightPopupEnabledproperty.- Returns:
- the value of the lightWeightPopupEnabledproperty
- See Also:
- setLightWeightPopupEnabled(boolean)
 
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setEditable@BeanProperty(preferred=true, description="If true, the user can type a new value in the combo box.") public void setEditable(boolean aFlag) Determines whether theJComboBoxfield is editable. An editableJComboBoxallows the user to type into the field or selected an item from the list to initialize the field, after which it can be edited. (The editing affects only the field, the list item remains intact.) A non editableJComboBoxdisplays the selected item in the field, but the selection cannot be modified.- Parameters:
- aFlag- a boolean value, where true indicates that the field is editable
 
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isEditablepublic boolean isEditable() Returns true if theJComboBoxis editable. By default, a combo box is not editable.- Returns:
- true if the JComboBoxis editable, else false
 
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setMaximumRowCount@BeanProperty(preferred=true, description="The maximum number of rows the popup should have") public void setMaximumRowCount(int count) Sets the maximum number of rows theJComboBoxdisplays. If the number of objects in the model is greater than count, the combo box uses a scrollbar.- Parameters:
- count- an integer specifying the maximum number of items to display in the list before using a scrollbar
 
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getMaximumRowCountpublic int getMaximumRowCount() Returns the maximum number of items the combo box can display without a scrollbar- Returns:
- an integer specifying the maximum number of items that are displayed in the list before using a scrollbar
 
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setRenderer@BeanProperty(expert=true, description="The renderer that paints the item selected in the list.") public void setRenderer(ListCellRenderer<? super E> aRenderer) Sets the renderer that paints the list items and the item selected from the list in the JComboBox field. The renderer is used if the JComboBox is not editable. If it is editable, the editor is used to render and edit the selected item.The default renderer displays a string or an icon. Other renderers can handle graphic images and composite items. To display the selected item, aRenderer.getListCellRendererComponentis called, passing the list object and an index of -1.- Parameters:
- aRenderer- the- ListCellRendererthat displays the selected item
- See Also:
- setEditor(javax.swing.ComboBoxEditor)
 
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getRendererpublic ListCellRenderer<? super E> getRenderer() Returns the renderer used to display the selected item in theJComboBoxfield.- Returns:
- the ListCellRendererthat displays the selected item.
 
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setEditor@BeanProperty(expert=true, description="The editor that combo box uses to edit the current value") public void setEditor(ComboBoxEditor anEditor) Sets the editor used to paint and edit the selected item in theJComboBoxfield. The editor is used only if the receivingJComboBoxis editable. If not editable, the combo box uses the renderer to paint the selected item.- Parameters:
- anEditor- the- ComboBoxEditorthat displays the selected item
- See Also:
- setRenderer(javax.swing.ListCellRenderer<? super E>)
 
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getEditorpublic ComboBoxEditor getEditor() Returns the editor used to paint and edit the selected item in theJComboBoxfield.- Returns:
- the ComboBoxEditorthat displays the selected item
 
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setSelectedItem@BeanProperty(bound=false, preferred=true, description="Sets the selected item in the JComboBox.") public void setSelectedItem(Object anObject) Sets the selected item in the combo box display area to the object in the argument. IfanObjectis in the list, the display area showsanObjectselected.If anObjectis not in the list and the combo box is uneditable, it will not change the current selection. For editable combo boxes, the selection will change toanObject.If this constitutes a change in the selected item, ItemListeners added to the combo box will be notified with one or twoItemEvents. If there is a current selected item, anItemEventwill be fired and the state change will beItemEvent.DESELECTED. IfanObjectis in the list and is not currently selected then anItemEventwill be fired and the state change will beItemEvent.SELECTED.ActionListeners added to the combo box will be notified with anActionEventwhen this method is called.- Parameters:
- anObject- the list object to select; use- nullto clear the selection
 
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getSelectedItempublic Object getSelectedItem() Returns the current selected item.If the combo box is editable, then this value may not have been added to the combo box with addItem,insertItemAtor the data constructors.- Returns:
- the current selected Object
- See Also:
- setSelectedItem(java.lang.Object)
 
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setSelectedIndex@BeanProperty(bound=false, preferred=true, description="The item at index is selected.") public void setSelectedIndex(int anIndex) Selects the item at indexanIndex.- Parameters:
- anIndex- an integer specifying the list item to select, where 0 specifies the first item in the list and -1 indicates no selection
- Throws:
- IllegalArgumentException- if- anIndex< -1 or- anIndexis greater than or equal to size
 
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getSelectedIndexpublic int getSelectedIndex() Returns the first item in the list that matches the given item. The result is not always defined if theJComboBoxallows selected items that are not in the list. Returns -1 if there is no selected item or if the user specified an item which is not in the list.- Returns:
- an integer specifying the currently selected list item, where 0 specifies the first item in the list; or -1 if no item is selected or if the currently selected item is not in the list
 
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getPrototypeDisplayValuepublic E getPrototypeDisplayValue() Returns the "prototypical display" value - an Object used for the calculation of the display height and width.- Returns:
- the value of the prototypeDisplayValueproperty
- Since:
- 1.4
- See Also:
- setPrototypeDisplayValue(E)
 
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setPrototypeDisplayValue@BeanProperty(visualUpdate=true, description="The display prototype value, used to compute display width and height.") public void setPrototypeDisplayValue(E prototypeDisplayValue) Sets the prototype display value used to calculate the size of the display for the UI portion.If a prototype display value is specified, the preferred size of the combo box is calculated by configuring the renderer with the prototype display value and obtaining its preferred size. Specifying the preferred display value is often useful when the combo box will be displaying large amounts of data. If no prototype display value has been specified, the renderer must be configured for each value from the model and its preferred size obtained, which can be relatively expensive. - Parameters:
- prototypeDisplayValue- the prototype display value
- Since:
- 1.4
- See Also:
- getPrototypeDisplayValue()
 
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addItempublic void addItem(E item) Adds an item to the item list. This method works only if theJComboBoxuses a mutable data model.Warning: Focus and keyboard navigation problems may arise if you add duplicate String objects. A workaround is to add new objects instead of String objects and make sure that the toString() method is defined. For example: comboBox.addItem(makeObj("Item 1")); comboBox.addItem(makeObj("Item 1")); ... private Object makeObj(final String item) { return new Object() { public String toString() { return item; } }; }- Parameters:
- item- the item to add to the list
- See Also:
- MutableComboBoxModel
 
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insertItemAtpublic void insertItemAt(E item, int index) Inserts an item into the item list at a given index. This method works only if theJComboBoxuses a mutable data model.- Parameters:
- item- the item to add to the list
- index- an integer specifying the position at which to add the item
- See Also:
- MutableComboBoxModel
 
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removeItempublic void removeItem(Object anObject) Removes an item from the item list. This method works only if theJComboBoxuses a mutable data model.- Parameters:
- anObject- the object to remove from the item list
- See Also:
- MutableComboBoxModel
 
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removeItemAtpublic void removeItemAt(int anIndex) Removes the item atanIndexThis method works only if theJComboBoxuses a mutable data model.- Parameters:
- anIndex- an int specifying the index of the item to remove, where 0 indicates the first item in the list
- See Also:
- MutableComboBoxModel
 
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removeAllItemspublic void removeAllItems() Removes all items from the item list.
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showPopuppublic void showPopup() Causes the combo box to display its popup window.- See Also:
- setPopupVisible(boolean)
 
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hidePopuppublic void hidePopup() Causes the combo box to close its popup window.- See Also:
- setPopupVisible(boolean)
 
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setPopupVisiblepublic void setPopupVisible(boolean v) Sets the visibility of the popup.- Parameters:
- v- if- trueshows the popup, otherwise, hides the popup.
 
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isPopupVisiblepublic boolean isPopupVisible() Determines the visibility of the popup.- Returns:
- true if the popup is visible, otherwise returns false
 
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addItemListenerpublic void addItemListener(ItemListener aListener) Adds anItemListener.aListenerwill receive one or twoItemEvents when the selected item changes.- Specified by:
- addItemListenerin interface- ItemSelectable
- Parameters:
- aListener- the- ItemListenerthat is to be notified
- See Also:
- setSelectedItem(java.lang.Object)
 
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removeItemListenerpublic void removeItemListener(ItemListener aListener) Removes anItemListener.- Specified by:
- removeItemListenerin interface- ItemSelectable
- Parameters:
- aListener- the- ItemListenerto remove
- See Also:
- ItemEvent
 
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getItemListeners@BeanProperty(bound=false) public ItemListener[] getItemListeners() Returns an array of all theItemListeners added to this JComboBox with addItemListener().- Returns:
- all of the ItemListeners added or an empty array if no listeners have been added
- Since:
- 1.4
 
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addActionListenerpublic void addActionListener(ActionListener l) Adds anActionListener.The ActionListenerwill receive anActionEventwhen a selection has been made. If the combo box is editable, then anActionEventwill be fired when editing has stopped.- Parameters:
- l- the- ActionListenerthat is to be notified
- See Also:
- setSelectedItem(java.lang.Object)
 
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removeActionListenerpublic void removeActionListener(ActionListener l) Removes anActionListener.- Parameters:
- l- the- ActionListenerto remove
 
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getActionListeners@BeanProperty(bound=false) public ActionListener[] getActionListeners() Returns an array of all theActionListeners added to this JComboBox with addActionListener().- Returns:
- all of the ActionListeners added or an empty array if no listeners have been added
- Since:
- 1.4
 
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addPopupMenuListenerpublic void addPopupMenuListener(PopupMenuListener l) Adds aPopupMenulistener which will listen to notification messages from the popup portion of the combo box.For all standard look and feels shipped with Java, the popup list portion of combo box is implemented as a JPopupMenu. A custom look and feel may not implement it this way and will therefore not receive the notification.- Parameters:
- l- the- PopupMenuListenerto add
- Since:
- 1.4
 
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removePopupMenuListenerpublic void removePopupMenuListener(PopupMenuListener l) Removes aPopupMenuListener.- Parameters:
- l- the- PopupMenuListenerto remove
- Since:
- 1.4
- See Also:
- addPopupMenuListener(javax.swing.event.PopupMenuListener)
 
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getPopupMenuListeners@BeanProperty(bound=false) public PopupMenuListener[] getPopupMenuListeners() Returns an array of all thePopupMenuListeners added to this JComboBox with addPopupMenuListener().- Returns:
- all of the PopupMenuListeners added or an empty array if no listeners have been added
- Since:
- 1.4
 
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firePopupMenuWillBecomeVisiblepublic void firePopupMenuWillBecomeVisible() NotifiesPopupMenuListeners that the popup portion of the combo box will become visible.This method is public but should not be called by anything other than the UI delegate. - Since:
- 1.4
- See Also:
- addPopupMenuListener(javax.swing.event.PopupMenuListener)
 
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firePopupMenuWillBecomeInvisiblepublic void firePopupMenuWillBecomeInvisible() NotifiesPopupMenuListeners that the popup portion of the combo box has become invisible.This method is public but should not be called by anything other than the UI delegate. - Since:
- 1.4
- See Also:
- addPopupMenuListener(javax.swing.event.PopupMenuListener)
 
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firePopupMenuCanceledpublic void firePopupMenuCanceled() NotifiesPopupMenuListeners that the popup portion of the combo box has been canceled.This method is public but should not be called by anything other than the UI delegate. - Since:
- 1.4
- See Also:
- addPopupMenuListener(javax.swing.event.PopupMenuListener)
 
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setActionCommandpublic void setActionCommand(String aCommand) Sets the action command that should be included in the event sent to action listeners.- Parameters:
- aCommand- a string containing the "command" that is sent to action listeners; the same listener can then do different things depending on the command it receives
 
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getActionCommandpublic String getActionCommand() Returns the action command that is included in the event sent to action listeners.- Returns:
- the string containing the "command" that is sent to action listeners.
 
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setAction@BeanProperty(visualUpdate=true, description="the Action instance connected with this ActionEvent source") public void setAction(Action a) Sets theActionfor theActionEventsource. The newActionreplaces any previously setActionbut does not affectActionListenersindependently added withaddActionListener. If theActionis already a registeredActionListenerfor theActionEventsource, it is not re-registered.Setting the Actionresults in immediately changing all the properties described in Swing Components SupportingAction. Subsequently, the combobox's properties are automatically updated as theAction's properties change.This method uses three other methods to set and help track the Action's property values. It uses theconfigurePropertiesFromActionmethod to immediately change the combobox's properties. To track changes in theAction's property values, this method registers thePropertyChangeListenerreturned bycreateActionPropertyChangeListener. The defaultPropertyChangeListenerinvokes theactionPropertyChangedmethod when a property in theActionchanges.- Parameters:
- a- the- Actionfor the- JComboBox, or- null.
- Since:
- 1.3
- See Also:
- Action,- getAction(),- configurePropertiesFromAction(javax.swing.Action),- createActionPropertyChangeListener(javax.swing.Action),- actionPropertyChanged(javax.swing.Action, java.lang.String)
 
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getActionpublic Action getAction() Returns the currently setActionfor thisActionEventsource, ornullif noActionis set.- Returns:
- the Actionfor thisActionEventsource; ornull
- Since:
- 1.3
- See Also:
- Action,- setAction(javax.swing.Action)
 
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configurePropertiesFromActionprotected void configurePropertiesFromAction(Action a) Sets the properties on this combobox to match those in the specifiedAction. Refer to Swing Components SupportingActionfor more details as to which properties this sets.- Parameters:
- a- the- Actionfrom which to get the properties, or- null
- Since:
- 1.3
- See Also:
- Action,- setAction(javax.swing.Action)
 
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createActionPropertyChangeListenerprotected PropertyChangeListener createActionPropertyChangeListener(Action a) Creates and returns aPropertyChangeListenerthat is responsible for listening for changes from the specifiedActionand updating the appropriate properties.Warning: If you subclass this do not create an anonymous inner class. If you do the lifetime of the combobox will be tied to that of the Action.- Parameters:
- a- the combobox's action
- Returns:
- the PropertyChangeListener
- Since:
- 1.3
- See Also:
- Action,- setAction(javax.swing.Action)
 
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actionPropertyChangedprotected void actionPropertyChanged(Action action, String propertyName) Updates the combobox's state in response to property changes in associated action. This method is invoked from thePropertyChangeListenerreturned fromcreateActionPropertyChangeListener. Subclasses do not normally need to invoke this. Subclasses that support additionalActionproperties should override this andconfigurePropertiesFromAction.Refer to the table at Swing Components Supporting Actionfor a list of the properties this method sets.- Parameters:
- action- the- Actionassociated with this combobox
- propertyName- the name of the property that changed
- Since:
- 1.6
- See Also:
- Action,- configurePropertiesFromAction(javax.swing.Action)
 
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fireItemStateChangedprotected void fireItemStateChanged(ItemEvent e) Notifies all listeners that have registered interest for notification on this event type.- Parameters:
- e- the event of interest
- See Also:
- EventListenerList
 
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fireActionEventprotected void fireActionEvent() Notifies all listeners that have registered interest for notification on this event type.- See Also:
- EventListenerList
 
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selectedItemChangedprotected void selectedItemChanged() This protected method is implementation specific. Do not access directly or override.
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getSelectedObjects@BeanProperty(bound=false) public Object[] getSelectedObjects() Returns an array containing the selected item. This method is implemented for compatibility withItemSelectable.- Specified by:
- getSelectedObjectsin interface- ItemSelectable
- Returns:
- an array of Objectscontaining one element -- the selected item
 
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actionPerformedpublic void actionPerformed(ActionEvent e) This method is public as an implementation side effect. do not call or override.- Specified by:
- actionPerformedin interface- ActionListener
- Parameters:
- e- the event to be processed
 
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contentsChangedpublic void contentsChanged(ListDataEvent e) This method is public as an implementation side effect. do not call or override.- Specified by:
- contentsChangedin interface- ListDataListener
- Parameters:
- e- a- ListDataEventencapsulating the event information
 
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intervalAddedpublic void intervalAdded(ListDataEvent e) This method is public as an implementation side effect. do not call or override.- Specified by:
- intervalAddedin interface- ListDataListener
- Parameters:
- e- a- ListDataEventencapsulating the event information
 
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intervalRemovedpublic void intervalRemoved(ListDataEvent e) This method is public as an implementation side effect. do not call or override.- Specified by:
- intervalRemovedin interface- ListDataListener
- Parameters:
- e- a- ListDataEventencapsulating the event information
 
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selectWithKeyCharpublic boolean selectWithKeyChar(char keyChar) Selects the list item that corresponds to the specified keyboard character and returns true, if there is an item corresponding to that character. Otherwise, returns false.- Parameters:
- keyChar- a char, typically this is a keyboard key typed by the user
- Returns:
- trueif there is an item corresponding to that character. Otherwise, returns- false.
 
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setEnabled@BeanProperty(preferred=true, description="The enabled state of the component.") public void setEnabled(boolean b) Enables the combo box so that items can be selected. When the combo box is disabled, items cannot be selected and values cannot be typed into its field (if it is editable).- Overrides:
- setEnabledin class- JComponent
- Parameters:
- b- a boolean value, where true enables the component and false disables it
- See Also:
- Component.isEnabled(),- Component.isLightweight()
 
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configureEditorpublic void configureEditor(ComboBoxEditor anEditor, Object anItem) Initializes the editor with the specified item.- Parameters:
- anEditor- the- ComboBoxEditorthat displays the list item in the combo box field and allows it to be edited
- anItem- the object to display and edit in the field
 
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processKeyEventpublic void processKeyEvent(KeyEvent e) HandlesKeyEvents, looking for the Tab key. If the Tab key is found, the popup window is closed.- Overrides:
- processKeyEventin class- JComponent
- Parameters:
- e- the- KeyEventcontaining the keyboard key that was pressed
- See Also:
- KeyEvent,- KeyListener,- KeyboardFocusManager,- DefaultKeyboardFocusManager,- Component.processEvent(java.awt.AWTEvent),- Component.dispatchEvent(java.awt.AWTEvent),- Component.addKeyListener(java.awt.event.KeyListener),- Component.enableEvents(long),- Component.isShowing()
 
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setKeySelectionManager@BeanProperty(bound=false, expert=true, description="The objects that changes the selection when a key is pressed.") public void setKeySelectionManager(JComboBox.KeySelectionManager aManager) Sets the object that translates a keyboard character into a list selection. Typically, the first selection with a matching first character becomes the selected item.- Parameters:
- aManager- a key selection manager
 
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getKeySelectionManagerpublic JComboBox.KeySelectionManager getKeySelectionManager() Returns the list's key-selection manager.- Returns:
- the KeySelectionManagercurrently in use
 
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getItemCount@BeanProperty(bound=false) public int getItemCount() Returns the number of items in the list.- Returns:
- an integer equal to the number of items in the list
 
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getItemAtpublic E getItemAt(int index) Returns the list item at the specified index. Ifindexis out of range (less than zero or greater than or equal to size) it will returnnull.- Parameters:
- index- an integer indicating the list position, where the first item starts at zero
- Returns:
- the item at that list position; or
                  nullif out of range
 
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createDefaultKeySelectionManagerprotected JComboBox.KeySelectionManager createDefaultKeySelectionManager() Returns an instance of the default key-selection manager.- Returns:
- the KeySelectionManagercurrently used by the list
- See Also:
- setKeySelectionManager(javax.swing.JComboBox.KeySelectionManager)
 
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paramStringprotected String paramString() Returns a string representation of thisJComboBox. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not benull.- Overrides:
- paramStringin class- JComponent
- Returns:
- a string representation of this JComboBox
 
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getAccessibleContext@BeanProperty(bound=false) public AccessibleContext getAccessibleContext() Gets the AccessibleContext associated with this JComboBox. For combo boxes, the AccessibleContext takes the form of an AccessibleJComboBox. A new AccessibleJComboBox instance is created if necessary.- Specified by:
- getAccessibleContextin interface- Accessible
- Overrides:
- getAccessibleContextin class- Component
- Returns:
- an AccessibleJComboBox that serves as the AccessibleContext of this JComboBox
 
 
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