Action (Java 2 Platform SE 5.0) (original) (raw)

javax.swing

Interface Action

All Superinterfaces:

ActionListener, EventListener

All Known Implementing Classes:

AbstractAction, BasicDesktopPaneUI.CloseAction, BasicDesktopPaneUI.MaximizeAction, BasicDesktopPaneUI.MinimizeAction, BasicDesktopPaneUI.NavigateAction, BasicDesktopPaneUI.OpenAction, BasicFileChooserUI.ApproveSelectionAction, BasicFileChooserUI.CancelSelectionAction, BasicFileChooserUI.ChangeToParentDirectoryAction, BasicFileChooserUI.GoHomeAction, BasicFileChooserUI.NewFolderAction, BasicFileChooserUI.UpdateAction, BasicInternalFrameTitlePane.CloseAction, BasicInternalFrameTitlePane.IconifyAction, BasicInternalFrameTitlePane.MaximizeAction, BasicInternalFrameTitlePane.MoveAction, BasicInternalFrameTitlePane.RestoreAction, BasicInternalFrameTitlePane.SizeAction, BasicSliderUI.ActionScroller, BasicTreeUI.TreeCancelEditingAction, BasicTreeUI.TreeHomeAction, BasicTreeUI.TreeIncrementAction, BasicTreeUI.TreePageAction, BasicTreeUI.TreeToggleAction, BasicTreeUI.TreeTraverseAction, DefaultEditorKit.BeepAction, DefaultEditorKit.CopyAction, DefaultEditorKit.CutAction, DefaultEditorKit.DefaultKeyTypedAction, DefaultEditorKit.InsertBreakAction, DefaultEditorKit.InsertContentAction, DefaultEditorKit.InsertTabAction, DefaultEditorKit.PasteAction, HTMLEditorKit.HTMLTextAction, HTMLEditorKit.InsertHTMLTextAction, MetalFileChooserUI.DirectoryComboBoxAction, StyledEditorKit.AlignmentAction, StyledEditorKit.BoldAction, StyledEditorKit.FontFamilyAction, StyledEditorKit.FontSizeAction, StyledEditorKit.ForegroundAction, StyledEditorKit.ItalicAction, StyledEditorKit.StyledTextAction, StyledEditorKit.UnderlineAction, TextAction

public interface Action

extends ActionListener

The Action interface provides a useful extension to theActionListener 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. Certain containers, including menus and tool bars, know how to add anAction object. When an Action object is added to such a container, the container:

1. Creates a component that is appropriate for that container (a tool bar creates a button component, for example).
2. Gets the appropriate property(s) from the Action object to customize the component (for example, the icon image and flyover text).
3. Checks the initial state of the Action object to determine if it is enabled or disabled, and renders the component in the appropriate fashion.
4. Registers a listener with the Action object so that is notified of state changes. When the Action object changes from enabled to disabled, or back, the container makes the appropriate revisions to the event-generation mechanisms and renders the component accordingly. For example, both a menu item and a toolbar button could access aCut action object. The text associated with the object is specified as "Cut", and an image depicting a pair of scissors is specified as its icon. The Cut action-object can then be added to a menu and to a tool bar. Each container does the appropriate things with the object, and invokes its actionPerformed method when the component associated with it is activated. The application can then disable or enable the application object without worrying about what user-interface components are connected to it.

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'ssetEnabled 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.

See Also:

AbstractAction

DEFAULT

static final String DEFAULT

Not currently used.

See Also:

Constant Field Values

NAME

static final String NAME

The key used for storing the String name for the action, used for a menu or button.

See Also:

Constant Field Values

SHORT_DESCRIPTION

static final String SHORT_DESCRIPTION

The key used for storing a short String description for the action, used for tooltip text.

See Also:

Constant Field Values

LONG_DESCRIPTION

static final String LONG_DESCRIPTION

The key used for storing a longer String description for the action, could be used for context-sensitive help.

See Also:

Constant Field Values

SMALL_ICON

static final String SMALL_ICON

The key used for storing a small Icon, such as ImageIcon, for the action, used for toolbar buttons.

See Also:

Constant Field Values

ACTION_COMMAND_KEY

static final String ACTION_COMMAND_KEY

The key used to determine the command String for theActionEvent that will be created when anAction is going to be notified as the result of residing in a Keymap associated with aJComponent.

See Also:

Constant Field Values

ACCELERATOR_KEY

static final String ACCELERATOR_KEY

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

Since:

1.3

See Also:

Constant Field Values

MNEMONIC_KEY

static final String MNEMONIC_KEY

The key used for storing a KeyEvent to be used as the mnemonic for the action.

Since:

1.3

See Also:

Constant Field Values

getValue

Object getValue(String key)

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

See Also:

[putValue(java.lang.String, java.lang.Object)](../../javax/swing/Action.html#putValue%28java.lang.String, java.lang.Object%29)

putValue

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 - a String containing the key

value - an Object value

setEnabled

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 - true to enable this Action, false to disable it

isEnabled

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:

true if this Action is enabled

addPropertyChangeListener

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 - a PropertyChangeListener object

removePropertyChangeListener

void removePropertyChangeListener(PropertyChangeListener listener)

Removes a PropertyChange listener.

Parameters:

listener - a PropertyChangeListener object

See Also:

addPropertyChangeListener(java.beans.PropertyChangeListener)

Submit a bug or feature
For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright © 2004, 2010 Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.