OpenJDK 27 · javax.swing.Action · APIdia, the JavaDoc alternative

The Action interface provides a useful extension to the ActionListener interface in cases where the same functionality may be accessed by several controls.

In addition to the actionPerformed method defined by the ActionListener interface, this interface allows the application to define, in a single place:

One or more text strings that describe the function. These strings can be used, for example, to display the flyover text for a button or to set the text in a menu item.
One or more icons that depict the function. These icons can be used for the images in a menu control, or for composite entries in a more sophisticated user interface.
The enabled/disabled state of the functionality. Instead of having to separately disable the menu item and the toolbar button, the application can disable the function that implements this interface. All components which are registered as listeners for the state change then know to disable event generation for that item and to modify the display accordingly.

This interface can be added to an existing class or used to create an adapter (typically, by subclassing AbstractAction). The Action object can then be added to multiple Action-aware containers and connected to Action-capable components. The GUI controls can then be activated or deactivated all at once by invoking the Action object's setEnabled method.

Note that Action implementations tend to be more expensive in terms of storage than a typical ActionListener, which does not offer the benefits of centralized control of functionality and broadcast of property changes. For this reason, you should take care to only use Actions where their benefits are desired, and use simple ActionListeners elsewhere.

Swing Components Supporting `Action`

Many of Swing's components have an Action property. When an Action is set on a component, the following things happen:

The Action is added as an ActionListener to the component.
The component configures some of its properties to match the Action.
The component installs a PropertyChangeListener on the Action so that the component can change its properties to reflect changes in the Action's properties.

The following table describes the properties used by Swing components that support Actions. In the table, button refers to any AbstractButton subclass, which includes not only JButton but also classes such as JMenuItem. Unless otherwise stated, a null property value in an Action (or a Action that is null) results in the button's corresponding property being set to null.

Supported Action properties
Component Property	Components	Action Key	Notes
`enabled`	All	The `isEnabled` method
`toolTipText`	All	`SHORT_DESCRIPTION`
`actionCommand`	All	`ACTION_COMMAND_KEY`
`mnemonic`	All buttons	`MNEMONIC_KEY`	A `null` value or `Action` results in the button's `mnemonic` property being set to `'\0'`.
`text`	All buttons	`NAME`	If you do not want the text of the button to mirror that of the `Action`, set the property `hideActionText` to `true`. If `hideActionText` is `true`, setting the `Action` changes the text of the button to `null` and any changes to `NAME` are ignored. `hideActionText` is useful for tool bar buttons that typically only show an `Icon`. `JToolBar.add(Action)` sets the property to `true` if the `Action` has a non-`null` value for `LARGE_ICON_KEY` or `SMALL_ICON`.
`displayedMnemonicIndex`	All buttons	`DISPLAYED_MNEMONIC_INDEX_KEY`	If the value of `DISPLAYED_MNEMONIC_INDEX_KEY` is beyond the bounds of the text, it is ignored. When `setAction` is called, if the value from the `Action` is `null`, the displayed mnemonic index is not updated. In any subsequent changes to `DISPLAYED_MNEMONIC_INDEX_KEY`, `null` is treated as -1.
`icon`	All buttons except of `JCheckBox`, `JToggleButton` and `JRadioButton`.	either `LARGE_ICON_KEY` or `SMALL_ICON`	The `JMenuItem` subclasses only use `SMALL_ICON`. All other buttons will use `LARGE_ICON_KEY`; if the value is `null` they use `SMALL_ICON`.
`accelerator`	All `JMenuItem` subclasses, with the exception of `JMenu`.	`ACCELERATOR_KEY`
`selected`	`JToggleButton`, `JCheckBox`, `JRadioButton`, `JCheckBoxMenuItem` and `JRadioButtonMenuItem`	`SELECTED_KEY`	Components that honor this property only use the value if it is `non-null`. For example, if you set an `Action` that has a `null` value for `SELECTED_KEY` on a `JToggleButton`, the `JToggleButton` will not update it's selected state in any way. Similarly, any time the `JToggleButton`'s selected state changes it will only set the value back on the `Action` if the `Action` has a `non-null` value for `SELECTED_KEY`. Components that honor this property keep their selected state in sync with this property. When the same `Action` is used with multiple components, all the components keep their selected state in sync with this property. Mutually exclusive buttons, such as `JToggleButton`s in a `ButtonGroup`, force only one of the buttons to be selected. As such, do not use the same `Action` that defines a value for the `SELECTED_KEY` property with multiple mutually exclusive buttons.

JPopupMenu, JToolBar and JMenu all provide convenience methods for creating a component and setting the Action on the corresponding component. Refer to each of these classes for more information.

Action uses PropertyChangeListener to inform listeners the Action has changed. The beans specification indicates that a null property name can be used to indicate multiple values have changed. By default Swing components that take an Action do not handle such a change. To indicate that Swing should treat null according to the beans specification set the system property swing.actions.reconfigureOnNull to the String value true.

Field Summary

Modifier and Type	Field and Description
public static final String	ACCELERATOR_KEY The key used for storing a `KeyStroke` to be used as the accelerator for the action.
public static final String	ACTION_COMMAND_KEY The key used to determine the command `String` for the `ActionEvent` that will be created when an `Action` is going to be notified as the result of residing in a `Keymap` associated with a `JComponent`.
public static final String	DEFAULT Not currently used.
public static final String	DISPLAYED_MNEMONIC_INDEX_KEY The key used for storing an `Integer` that corresponds to the index in the text (identified by the `NAME` property) that the decoration for a mnemonic should be rendered at.
public static final String	LARGE_ICON_KEY The key used for storing an `Icon`.
public static final String	LONG_DESCRIPTION The key used for storing a longer `String` description for the action, could be used for context-sensitive help.
public static final String	MNEMONIC_KEY The key used for storing an `Integer` that corresponds to one of the `KeyEvent` key codes.
public static final String	NAME The key used for storing the `String` name for the action, used for a menu or button.
public static final String	SELECTED_KEY The key used for storing a `Boolean` that corresponds to the selected state.
public static final String	SHORT_DESCRIPTION The key used for storing a short `String` description for the action, used for tooltip text.
public static final String	SMALL_ICON The key used for storing a small `Icon`, such as `ImageIcon`.

Modifier and Type	Method and Description
public default boolean	Returns: `true` if the action should be performed with the sender object, must be false if the action is disabled. accept(Object the object to check, can be null sender) Determines whether the action should be performed with the specified sender object.
public void	addPropertyChangeListener(PropertyChangeListener a `PropertyChangeListener` object listener) Adds a `PropertyChange` listener.
public Object	Returns: the `Object` value getValue(String a `String` containing the key key) Gets one of this object's properties using the associated key.
public boolean	Returns: true if this `Action` is enabled isEnabled() Returns the enabled state of the `Action`.
public void	putValue(String a `String` containing the key key, Object an `Object` value value) Sets one of this object's properties using the associated key.
public void	removePropertyChangeListener(PropertyChangeListener a `PropertyChangeListener` object listener) Removes a `PropertyChange` listener.
public void	setEnabled(boolean true to enable this `Action`, false to disable it b) Sets the enabled state of the `Action`.

Field Detail

ACCELERATOR_KEY back to summary

ACCELERATOR_KEY	back to summary
public static final String ACCELERATOR_KEY The key used for storing a `KeyStroke` to be used as the accelerator for the action. Since 1.3

public static final String ACCELERATOR_KEY

The key used for storing a KeyStroke to be used as the accelerator for the action.

Since: 1.3

ACTION_COMMAND_KEY	back to summary
public static final String ACTION_COMMAND_KEY The key used to determine the command `String` for the `ActionEvent` that will be created when an `Action` is going to be notified as the result of residing in a `Keymap` associated with a `JComponent`.

DEFAULT	back to summary
public static final String DEFAULT Not currently used.

DISPLAYED_MNEMONIC_INDEX_KEY back to summary

DISPLAYED_MNEMONIC_INDEX_KEY	back to summary
public static final String DISPLAYED_MNEMONIC_INDEX_KEY The key used for storing an `Integer` that corresponds to the index in the text (identified by the `NAME` property) that the decoration for a mnemonic should be rendered at. If the value of this property is greater than or equal to the length of the text, it will treated as -1. Note the value of this field is prefixed with 'Swing' to avoid possible collisions with existing `Actions`. Since 1.6 See Also `AbstractButton#setDisplayedMnemonicIndex`

public static final String DISPLAYED_MNEMONIC_INDEX_KEY

The key used for storing an Integer that corresponds to the index in the text (identified by the NAME property) that the decoration for a mnemonic should be rendered at. If the value of this property is greater than or equal to the length of the text, it will treated as -1.

Note

the value of this field is prefixed with 'Swing' to avoid possible collisions with existing Actions.

Since: 1.6
See Also: AbstractButton#setDisplayedMnemonicIndex

LARGE_ICON_KEY back to summary

LARGE_ICON_KEY	back to summary
public static final String LARGE_ICON_KEY The key used for storing an `Icon`. This is typically used by buttons, such as `JButton` and `JToggleButton`. If the same `Action` is used with menus and buttons you'll typically specify both a `SMALL_ICON` and a `LARGE_ICON_KEY`. The menu will use the `SMALL_ICON` and the button the `LARGE_ICON_KEY`. Note the value of this field is prefixed with 'Swing' to avoid possible collisions with existing `Actions`. Since 1.6

public static final String LARGE_ICON_KEY

The key used for storing an Icon. This is typically used by buttons, such as JButton and JToggleButton.

If the same Action is used with menus and buttons you'll typically specify both a SMALL_ICON and a LARGE_ICON_KEY. The menu will use the SMALL_ICON and the button the LARGE_ICON_KEY.

Note

the value of this field is prefixed with 'Swing' to avoid possible collisions with existing Actions.

Since: 1.6

LONG_DESCRIPTION	back to summary
public static final String LONG_DESCRIPTION The key used for storing a longer `String` description for the action, could be used for context-sensitive help.

MNEMONIC_KEY back to summary

MNEMONIC_KEY	back to summary
public static final String MNEMONIC_KEY The key used for storing an `Integer` that corresponds to one of the `KeyEvent` key codes. The value is commonly used to specify a mnemonic. For example: `myAction.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_A)` sets the mnemonic of `myAction` to 'a', while `myAction.putValue(Action.MNEMONIC_KEY, KeyEvent.getExtendedKeyCodeForChar('ф'))` sets the mnemonic of `myAction` to Cyrillic letter "Ef". Since 1.3

public static final String MNEMONIC_KEY

The key used for storing an Integer that corresponds to one of the KeyEvent key codes. The value is commonly used to specify a mnemonic. For example: myAction.putValue(Action.MNEMONIC_KEY, KeyEvent.VK_A) sets the mnemonic of myAction to 'a', while myAction.putValue(Action.MNEMONIC_KEY, KeyEvent.getExtendedKeyCodeForChar('ф')) sets the mnemonic of myAction to Cyrillic letter "Ef".

Since: 1.3

NAME	back to summary
public static final String NAME The key used for storing the `String` name for the action, used for a menu or button.

SELECTED_KEY back to summary

SELECTED_KEY	back to summary
public static final String SELECTED_KEY The key used for storing a `Boolean` that corresponds to the selected state. This is typically used only for components that have a meaningful selection state. For example, `JRadioButton` and `JCheckBox` make use of this but instances of `JMenu` don't. This property differs from the others in that it is both read by the component and set by the component. For example, if an `Action` is attached to a `JCheckBox` the selected state of the `JCheckBox` will be set from that of the `Action`. If the user clicks on the `JCheckBox` the selected state of the `JCheckBox` and the `Action` will both be updated. Note the value of this field is prefixed with 'Swing' to avoid possible collisions with existing `Actions`. Since 1.6

public static final String SELECTED_KEY

The key used for storing a Boolean that corresponds to the selected state. This is typically used only for components that have a meaningful selection state. For example, JRadioButton and JCheckBox make use of this but instances of JMenu don't.

This property differs from the others in that it is both read by the component and set by the component. For example, if an Action is attached to a JCheckBox the selected state of the JCheckBox will be set from that of the Action. If the user clicks on the JCheckBox the selected state of the JCheckBox and the Action will both be updated.

Note

the value of this field is prefixed with 'Swing' to avoid possible collisions with existing Actions.

Since: 1.6

SHORT_DESCRIPTION	back to summary
public static final String SHORT_DESCRIPTION The key used for storing a short `String` description for the action, used for tooltip text.

SMALL_ICON back to summary

SMALL_ICON	back to summary
public static final String SMALL_ICON The key used for storing a small `Icon`, such as `ImageIcon`. This is typically used with menus such as `JMenuItem`. If the same `Action` is used with menus and buttons you'll typically specify both a `SMALL_ICON` and a `LARGE_ICON_KEY`. The menu will use the `SMALL_ICON` and the button will use the `LARGE_ICON_KEY`.

public static final String SMALL_ICON

The key used for storing a small Icon, such as ImageIcon. This is typically used with menus such as JMenuItem.

If the same Action is used with menus and buttons you'll typically specify both a SMALL_ICON and a LARGE_ICON_KEY. The menu will use the SMALL_ICON and the button will use the LARGE_ICON_KEY.

Method Detail

accept back to summary

accept	back to summary
public default boolean accept(Object sender) Determines whether the action should be performed with the specified sender object. The `sender` can be `null`. The method must return false if the action is disabled. Parameters sender:Object the object to check, can be null Returns:boolean `true` if the action should be performed with the sender object, must be false if the action is disabled. See Also `isEnabled`, `setEnabled`

public default boolean accept(Object sender)

Determines whether the action should be performed with the specified sender object. The sender can be null. The method must return false if the action is disabled.

Parameters

sender:Object: the object to check, can be null

Returns:boolean

true if the action should be performed with the sender object, must be false if the action is disabled.

See Also

isEnabled, setEnabled

addPropertyChangeListener back to summary

addPropertyChangeListener	back to summary
public void addPropertyChangeListener(PropertyChangeListener listener) Adds a `PropertyChange` listener. Containers and attached components use these methods to register interest in this `Action` object. When its enabled state or other property changes, the registered listeners are informed of the change. Parameters listener:PropertyChangeListener a `PropertyChangeListener` object

public void addPropertyChangeListener(PropertyChangeListener listener)

Adds a PropertyChange listener. Containers and attached components use these methods to register interest in this Action object. When its enabled state or other property changes, the registered listeners are informed of the change.

Parameters

listener:PropertyChangeListener: a PropertyChangeListener object

getValue back to summary

getValue	back to summary
public Object getValue(String key) Gets one of this object's properties using the associated key. Parameters key:String a `String` containing the key Returns:Object the `Object` value See Also `putValue`

public Object getValue(String key)

Gets one of this object's properties using the associated key.

Parameters

key:String: a String containing the key

Returns:Object

the Object value

See Also

putValue

isEnabled back to summary

isEnabled	back to summary
public boolean isEnabled() Returns the enabled state of the `Action`. When enabled, any component associated with this object is active and able to fire this object's `actionPerformed` method. Returns:boolean true if this `Action` is enabled See Also `accept`

public boolean isEnabled()

Returns the enabled state of the Action. When enabled, any component associated with this object is active and able to fire this object's actionPerformed method.

Returns:boolean: true if this Action is enabled
See Also: accept

putValue back to summary

putValue	back to summary
public void putValue(String key, Object value) Sets one of this object's properties using the associated key. If the value has changed, a `PropertyChangeEvent` is sent to listeners. Parameters key:String a `String` containing the key value:Object an `Object` value

public void putValue(String key, Object value)

Sets one of this object's properties using the associated key. If the value has changed, a PropertyChangeEvent is sent to listeners.

Parameters

key:String: a String containing the key
value:Object: an Object value

removePropertyChangeListener back to summary

removePropertyChangeListener	back to summary
public void removePropertyChangeListener(PropertyChangeListener listener) Removes a `PropertyChange` listener. Parameters listener:PropertyChangeListener a `PropertyChangeListener` object See Also `addPropertyChangeListener`

public void removePropertyChangeListener(PropertyChangeListener listener)

Removes a PropertyChange listener.

Parameters

listener:PropertyChangeListener: a PropertyChangeListener object

See Also

addPropertyChangeListener

setEnabled back to summary

setEnabled	back to summary
public void setEnabled(boolean b) Sets the enabled state of the `Action`. When enabled, any component associated with this object is active and able to fire this object's `actionPerformed` method. If the value has changed, a `PropertyChangeEvent` is sent to listeners. Parameters b:boolean true to enable this `Action`, false to disable it See Also `accept`

public void setEnabled(boolean b)

Sets the enabled state of the Action. When enabled, any component associated with this object is active and able to fire this object's actionPerformed method. If the value has changed, a PropertyChangeEvent is sent to listeners.

Parameters

b:boolean: true to enable this Action, false to disable it

See Also

accept

public Interface Action

Swing Components Supporting `Action`

Field Summary

Method Summary

Field Detail

Method Detail

public Interface Action

Swing Components Supporting Action

Field Summary

Method Summary

Field Detail

Method Detail

Swing Components Supporting `Action`