DefaultButtonModel (Java SE 21 & JDK 21)
Description: declaration: module: java.desktop, package: javax.swing, class: DefaultButtonModel
Keywords: javax.swing.DefaultButtonModel class

Module java.desktop
Package javax.swing

# Class DefaultButtonModel

java.lang.Object
javax.swing.DefaultButtonModel

All Implemented Interfaces:
  `ItemSelectable`, `Serializable`, `ButtonModel`

Direct Known Subclasses:
  `JToggleButton.ToggleButtonModel`

public class DefaultButtonModel extends Object implements ButtonModel, Serializable
The default implementation of a `Button` component's data model.

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.beans` package. Please see `XMLEncoder`.

Since:
  1.2

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected String`
  `actionCommand`
  The action command string fired by the button.
  `static final int`
  `ARMED`
  Identifies the "armed" bit in the bitmask, which indicates partial commitment towards choosing/triggering the button.
  `protected ChangeEvent`
  `changeEvent`
  Only one `ChangeEvent` is needed per button model instance since the event's only state is the source property.
  `static final int`
  `ENABLED`
  Identifies the "enabled" bit in the bitmask, which indicates that the button can be selected by an input device (such as a mouse pointer).
  `protected ButtonGroup`
  `group`
  The button group that the button belongs to.
  `protected EventListenerList`
  `listenerList`
  Stores the listeners on this model.
  `protected int`
  `mnemonic`
  The button's mnemonic.
  `static final int`
  `PRESSED`
  Identifies the "pressed" bit in the bitmask, which indicates that the button is pressed.
  `static final int`
  `ROLLOVER`
  Identifies the "rollover" bit in the bitmask, which indicates that the mouse is over the button.
  `static final int`
  `SELECTED`
  Identifies the "selected" bit in the bitmask, which indicates that the button has been selected.
  `protected int`
  `stateMask`
  The bitmask used to store the state of the button.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `DefaultButtonModel()`
  Constructs a `DefaultButtonModel`.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `addActionListener(ActionListener l)`
  Adds an `ActionListener` to the model.
  `void`
  `addChangeListener(ChangeListener l)`
  Adds a `ChangeListener` to the model.
  `void`
  `addItemListener(ItemListener l)`
  Adds an `ItemListener` to the model.
  `protected void`
  `fireActionPerformed(ActionEvent e)`
  Notifies all listeners that have registered interest for notification on this event type.
  `protected void`
  `fireItemStateChanged(ItemEvent e)`
  Notifies all listeners that have registered interest for notification on this event type.
  `protected void`
  `fireStateChanged()`
  Notifies all listeners that have registered interest for notification on this event type.
  `String`
  `getActionCommand()`
  Returns the action command string for the button.
  `ActionListener[]`
  `getActionListeners()`
  Returns an array of all the action listeners registered on this `DefaultButtonModel`.
  `ChangeListener[]`
  `getChangeListeners()`
  Returns an array of all the change listeners registered on this `DefaultButtonModel`.
  `ButtonGroup`
  `getGroup()`
  Returns the group that the button belongs to.
  `ItemListener[]`
  `getItemListeners()`
  Returns an array of all the item listeners registered on this `DefaultButtonModel`.
  `<T extends EventListener>
  T[]`
  `getListeners(Class<T> listenerType)`
  Returns an array of all the objects currently registered as `FooListener`s upon this model.
  `int`
  `getMnemonic()`
  Gets the keyboard mnemonic for the button.
  `Object[]`
  `getSelectedObjects()`
  Overridden to return `null`.
  `boolean`
  `isArmed()`
  Indicates partial commitment towards triggering the button.
  `boolean`
  `isEnabled()`
  Indicates if the button can be selected or triggered by an input device, such as a mouse pointer.
  `boolean`
  `isPressed()`
  Indicates if the button is pressed.
  `boolean`
  `isRollover()`
  Indicates that the mouse is over the button.
  `boolean`
  `isSelected()`
  Indicates if the button has been selected.
  `void`
  `removeActionListener(ActionListener l)`
  Removes an `ActionListener` from the model.
  `void`
  `removeChangeListener(ChangeListener l)`
  Removes a `ChangeListener` from the model.
  `void`
  `removeItemListener(ItemListener l)`
  Removes an `ItemListener` from the model.
  `void`
  `setActionCommand(String actionCommand)`
  Sets the action command string that gets sent as part of the `ActionEvent` when the button is triggered.
  `void`
  `setArmed(boolean b)`
  Marks the button as armed or unarmed.
  `void`
  `setEnabled(boolean b)`
  Enables or disables the button.
  `void`
  `setGroup(ButtonGroup group)`
  Identifies the group the button belongs to -- needed for radio buttons, which are mutually exclusive within their group.
  `void`
  `setMnemonic(int key)`
  Sets the keyboard mnemonic (shortcut key or accelerator key) for the button.
  `void`
  `setPressed(boolean b)`
  Sets the button to pressed or unpressed.
  `void`
  `setRollover(boolean b)`
  Sets or clears the button's rollover state
  `void`
  `setSelected(boolean b)`
  Selects or deselects the button.

  ### Methods declared in class java.lang.Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Field Details

  - ### stateMask

    protected int stateMask
    The bitmask used to store the state of the button.

  - ### actionCommand

    protected String actionCommand
    The action command string fired by the button.

  - ### group

    protected ButtonGroup group
    The button group that the button belongs to.

  - ### mnemonic

    protected int mnemonic
    The button's mnemonic.

  - ### changeEvent

    protected transient ChangeEvent changeEvent
    Only one `ChangeEvent` is needed per button model instance since the event's only state is the source property. The source of events generated is always "this".

  - ### listenerList

    protected EventListenerList listenerList
    Stores the listeners on this model.

  - ### ARMED

    public static final int ARMED
    Identifies the "armed" bit in the bitmask, which indicates partial commitment towards choosing/triggering the button.
    See Also:
      - Constant Field Values

  - ### SELECTED

    public static final int SELECTED
    Identifies the "selected" bit in the bitmask, which indicates that the button has been selected. Only needed for certain types of buttons - such as radio button or check box.
    See Also:
      - Constant Field Values

  - ### PRESSED

    public static final int PRESSED
    Identifies the "pressed" bit in the bitmask, which indicates that the button is pressed.
    See Also:
      - Constant Field Values

  - ### ENABLED

    public static final int ENABLED
    Identifies the "enabled" bit in the bitmask, which indicates that the button can be selected by an input device (such as a mouse pointer).
    See Also:
      - Constant Field Values

  - ### ROLLOVER

    public static final int ROLLOVER
    Identifies the "rollover" bit in the bitmask, which indicates that the mouse is over the button.
    See Also:
      - Constant Field Values

- ## Constructor Details

  - ### DefaultButtonModel

    public DefaultButtonModel()
    Constructs a `DefaultButtonModel`.

- ## Method Details

  - ### setActionCommand

    public void setActionCommand(String actionCommand)
    Sets the action command string that gets sent as part of the `ActionEvent` when the button is triggered.
    Specified by:
      `setActionCommand` in interface `ButtonModel`
    Parameters:
      `actionCommand` - the `String` that identifies the generated event
    See Also:
      - `ButtonModel.getActionCommand()`
      - `ActionEvent.getActionCommand()`

  - ### getActionCommand

    public String getActionCommand()
    Returns the action command string for the button.
    Specified by:
      `getActionCommand` in interface `ButtonModel`
    Returns:
      the `String` that identifies the generated event
    See Also:
      - `ButtonModel.setActionCommand(java.lang.String)`

  - ### isArmed

    public boolean isArmed()
    Indicates partial commitment towards triggering the button.
    Specified by:
      `isArmed` in interface `ButtonModel`
    Returns:
      `true` if the button is armed, and ready to be triggered
    See Also:
      - `ButtonModel.setArmed(boolean)`

  - ### isSelected

    public boolean isSelected()
    Indicates if the button has been selected. Only needed for certain types of buttons - such as radio buttons and check boxes.
    Specified by:
      `isSelected` in interface `ButtonModel`
    Returns:
      `true` if the button is selected

  - ### isEnabled

    public boolean isEnabled()
    Indicates if the button can be selected or triggered by an input device, such as a mouse pointer.
    Specified by:
      `isEnabled` in interface `ButtonModel`
    Returns:
      `true` if the button is enabled

  - ### isPressed

    public boolean isPressed()
    Indicates if the button is pressed.
    Specified by:
      `isPressed` in interface `ButtonModel`
    Returns:
      `true` if the button is pressed

  - ### isRollover

    public boolean isRollover()
    Indicates that the mouse is over the button.
    Specified by:
      `isRollover` in interface `ButtonModel`
    Returns:
      `true` if the mouse is over the button

  - ### setArmed

    public void setArmed(boolean b)
    Marks the button as armed or unarmed.
    Specified by:
      `setArmed` in interface `ButtonModel`
    Parameters:
      `b` - whether or not the button should be armed

  - ### setEnabled

    public void setEnabled(boolean b)
    Enables or disables the button.
    Specified by:
      `setEnabled` in interface `ButtonModel`
    Parameters:
      `b` - whether or not the button should be enabled
    See Also:
      - `ButtonModel.isEnabled()`

  - ### setSelected

    public void setSelected(boolean b)
    Selects or deselects the button.
    Specified by:
      `setSelected` in interface `ButtonModel`
    Parameters:
      `b` - `true` selects the button, `false` deselects the button

  - ### setPressed

    public void setPressed(boolean b)
    Sets the button to pressed or unpressed.
    Specified by:
      `setPressed` in interface `ButtonModel`
    Parameters:
      `b` - whether or not the button should be pressed
    See Also:
      - `ButtonModel.isPressed()`

  - ### setRollover

    public void setRollover(boolean b)
    Sets or clears the button's rollover state
    Specified by:
      `setRollover` in interface `ButtonModel`
    Parameters:
      `b` - whether or not the button is in the rollover state
    See Also:
      - `ButtonModel.isRollover()`

  - ### setMnemonic

    public void setMnemonic(int key)
    Sets the keyboard mnemonic (shortcut key or accelerator key) for the button.
    Specified by:
      `setMnemonic` in interface `ButtonModel`
    Parameters:
      `key` - an int specifying the accelerator key

  - ### getMnemonic

    public int getMnemonic()
    Gets the keyboard mnemonic for the button.
    Specified by:
      `getMnemonic` in interface `ButtonModel`
    Returns:
      an int specifying the accelerator key
    See Also:
      - `ButtonModel.setMnemonic(int)`

  - ### addChangeListener

    public void addChangeListener(ChangeListener l)
    Adds a `ChangeListener` to the model.
    Specified by:
      `addChangeListener` in interface `ButtonModel`
    Parameters:
      `l` - the listener to add

  - ### removeChangeListener

    public void removeChangeListener(ChangeListener l)
    Removes a `ChangeListener` from the model.
    Specified by:
      `removeChangeListener` in interface `ButtonModel`
    Parameters:
      `l` - the listener to remove

  - ### getChangeListeners

    public ChangeListener[] getChangeListeners()
    Returns an array of all the change listeners registered on this `DefaultButtonModel`.
    Returns:
      all of this model's `ChangeListener`s or an empty array if no change listeners are currently registered
    Since:
      1.4
    See Also:
      - `addChangeListener(javax.swing.event.ChangeListener)`
      - `removeChangeListener(javax.swing.event.ChangeListener)`

  - ### fireStateChanged

    protected void fireStateChanged()
    Notifies all listeners that have registered interest for notification on this event type. The event instance is created lazily.
    See Also:
      - `EventListenerList`

  - ### addActionListener

    public void addActionListener(ActionListener l)
    Adds an `ActionListener` to the model.
    Specified by:
      `addActionListener` in interface `ButtonModel`
    Parameters:
      `l` - the listener to add

  - ### removeActionListener

    public void removeActionListener(ActionListener l)
    Removes an `ActionListener` from the model.
    Specified by:
      `removeActionListener` in interface `ButtonModel`
    Parameters:
      `l` - the listener to remove

  - ### getActionListeners

    public ActionListener[] getActionListeners()
    Returns an array of all the action listeners registered on this `DefaultButtonModel`.
    Returns:
      all of this model's `ActionListener`s or an empty array if no action listeners are currently registered
    Since:
      1.4
    See Also:
      - `addActionListener(java.awt.event.ActionListener)`
      - `removeActionListener(java.awt.event.ActionListener)`

  - ### fireActionPerformed

    protected void fireActionPerformed(ActionEvent e)
    Notifies all listeners that have registered interest for notification on this event type.
    Parameters:
      `e` - the `ActionEvent` to deliver to listeners
    See Also:
      - `EventListenerList`

  - ### addItemListener

    public void addItemListener(ItemListener l)
    Adds an `ItemListener` to the model.
    Specified by:
      `addItemListener` in interface `ButtonModel`
    Specified by:
      `addItemListener` in interface `ItemSelectable`
    Parameters:
      `l` - the listener to add
    See Also:
      - `ItemEvent`

  - ### removeItemListener

    public void removeItemListener(ItemListener l)
    Removes an `ItemListener` from the model.
    Specified by:
      `removeItemListener` in interface `ButtonModel`
    Specified by:
      `removeItemListener` in interface `ItemSelectable`
    Parameters:
      `l` - the listener to remove
    See Also:
      - `ItemEvent`

  - ### getItemListeners

    public ItemListener[] getItemListeners()
    Returns an array of all the item listeners registered on this `DefaultButtonModel`.
    Returns:
      all of this model's `ItemListener`s or an empty array if no item listeners are currently registered
    Since:
      1.4
    See Also:
      - `addItemListener(java.awt.event.ItemListener)`
      - `removeItemListener(java.awt.event.ItemListener)`

  - ### fireItemStateChanged

    protected void fireItemStateChanged(ItemEvent e)
    Notifies all listeners that have registered interest for notification on this event type.
    Parameters:
      `e` - the `ItemEvent` to deliver to listeners
    See Also:
      - `EventListenerList`

  - ### getListeners

    public <T extends EventListener> T[] getListeners(Class<T> listenerType)
    Returns an array of all the objects currently registered as `FooListener`s upon this model. `FooListener`s are registered using the `addFooListener` method.

    You can specify the `listenerType` argument with a class literal, such as `FooListener.class`. For example, you can query a `DefaultButtonModel` instance `m` for its action listeners with the following code:

        ActionListener[] als = (ActionListener[])(m.getListeners(ActionListener.class));

    If no such listeners exist, this method returns an empty array.
    Type Parameters:
      `T` - the type of requested listeners
    Parameters:
      `listenerType` - the type of listeners requested; this parameter should specify an interface that descends from `java.util.EventListener`
    Returns:
      an array of all objects registered as `FooListener`s on this model, or an empty array if no such listeners have been added
    Throws:
      `ClassCastException` - if `listenerType` doesn't specify a class or interface that implements `java.util.EventListener`
    Since:
      1.3
    See Also:
      - `getActionListeners()`
      - `getChangeListeners()`
      - `getItemListeners()`

  - ### getSelectedObjects

    public Object[] getSelectedObjects()
    Overridden to return `null`.
    Specified by:
      `getSelectedObjects` in interface `ItemSelectable`
    Returns:
      the list of selected objects, or `null`

  - ### setGroup

    public void setGroup(ButtonGroup group)
    Identifies the group the button belongs to -- needed for radio buttons, which are mutually exclusive within their group.
    Specified by:
      `setGroup` in interface `ButtonModel`
    Parameters:
      `group` - the `ButtonGroup` the button belongs to

  - ### getGroup

    public ButtonGroup getGroup()
    Returns the group that the button belongs to. Normally used with radio buttons, which are mutually exclusive within their group.
    Specified by:
      `getGroup` in interface `ButtonModel`
    Returns:
      the `ButtonGroup` that the button belongs to
    Since:
      1.3