Java Swing, 2nd Edition

The DefaultButtonModel Class

Swing provides an implementation of the ButtonModel interface called DefaultButtonModel. This class is used directly by the AbstractButton class and indirectly by the other button classes. JToggleButton defines an inner class extending DefaultButtonModel that it and its descendants use to manage their state data.

Properties

The DefaultButtonModel class gets most of its properties from ButtonModel. The default values set by this class are shown in Table 5-3.

Table 5-3. DefaultButtonModel properties

Property	Data type	get	is	set	Default value
actionCommand o	String	·		·	null
armed o	boolean		·	·	false
enabled o	boolean		·	·	true
group o, *	ButtonGroup	·		·	null
mnemonico	int	·		·	KeyEvent.VK_UNDEFINED
pressedo	boolean		·	·	false
rollovero	boolean		·	·	false
selectedo	boolean		·	·	false
selectedObjects	Object[]	·			null
ooverridden, *getter was introduced in SDK 1.3

The only property here that does not come from the ButtonModel interface is the selectedObjects property. DefaultButtonModel provides a getSelectedObjects( ) method because it is mandated by the ItemSelectable interface, but it always returns null. SDK 1.3 added the getGroup( ) method.

Events

The events fired by DefaultButtonModel are those required by ButtonModel and listed in Table 5-2. An ActionEvent is fired when the button is pressed, an ItemEvent is fired when the button’s state is changed, and a ChangeEvent is fired when a change has occurred to the button’s properties.

This class implements the following standard methods: ...