Class ValueChangeEvent<T>

java.lang.Object

java.util.EventObject

jakarta.faces.event.FacesEvent

jakarta.faces.event.ValueChangeEvent<T>

Type Parameters:

T - The generic type of changed value.

All Implemented Interfaces:

Serializable

public class ValueChangeEvent<T>
extends FacesEvent

A ValueChangeEvent is a notification that the local value of the source component has been change as a result of user interface activity. It is not fired unless validation of the new value was completed successfully.

See Also:

• Serialized Form

Field Summary

Fields inherited from class EventObject

source

Constructor Summary

Constructors

Constructor	Description
ValueChangeEvent(UIComponent component, T oldValue, T newValue)	Construct a new event object from the specified source component, old value, and new value.
ValueChangeEvent(FacesContext facesContext, UIComponent component, T oldValue, T newValue)	Construct a new event object from the Faces context, specified source component, old value and new value.

Method Summary

Modifier and Type	Method	Description
T	getNewValue()	Return the current local value of the source UIComponent.
T	getOldValue()	Return the previous local value of the source UIComponent.
boolean	isAppropriateListener(FacesListener listener)	Return true if this FacesListener is an instance of a listener class that this event supports.
void	processListener(FacesListener listener)	Broadcast this FacesEvent to the specified FacesListener, by whatever mechanism is appropriate.

Methods inherited from class FacesEvent

getComponent, getFacesContext, getPhaseId, queue, setPhaseId

Modifier and Type	Method	Description
UIComponent	getComponent()	Return the source UIComponent that sent this event.
FacesContext	getFacesContext()	Get the Faces context.
PhaseId	getPhaseId()	Return the identifier of the request processing phase during which this event should be delivered.
void	queue()	Convenience method to queue this event for broadcast at the end of the current request processing lifecycle phase.
void	setPhaseId(PhaseId phaseId)	Set the PhaseId during which this event will be delivered.

Methods inherited from class EventObject

getSource, toString

Methods inherited from class Object

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

Constructor Details

ValueChangeEvent

public ValueChangeEvent(UIComponent component,
 T oldValue,
 T newValue)

Construct a new event object from the specified source component, old value, and new value.

The default PhaseId for this event is PhaseId.ANY_PHASE.

Parameters:

component - Source UIComponent for this event

oldValue - The previous local value of this UIComponent

newValue - The new local value of thie UIComponent

Throws:

IllegalArgumentException - if component is null

ValueChangeEvent

public ValueChangeEvent(FacesContext facesContext,
 UIComponent component,
 T oldValue,
 T newValue)

Construct a new event object from the Faces context, specified source component, old value and new value.

The default PhaseId for this event is PhaseId.ANY_PHASE.

Parameters:

facesContext - the Faces context.

component - Source UIComponent for this event

oldValue - The previous local value of this UIComponent

newValue - The new local value of thie UIComponent

Throws:

IllegalArgumentException - if component is null

Method Details

getOldValue

public T getOldValue()

Return the previous local value of the source UIComponent.

Returns:

the previous local value

getNewValue

public T getNewValue()

Return the current local value of the source UIComponent.

Returns:

the current local value

isAppropriateListener

public boolean isAppropriateListener(FacesListener listener)

Description copied from class: FacesEvent

Return true if this FacesListener is an instance of a listener class that this event supports. Typically, this will be accomplished by an "instanceof" check on the listener class.

Specified by:

isAppropriateListener in class FacesEvent

Parameters:

listener - FacesListener to evaluate

Returns:

true if it is the appropriate instance, false otherwise.

processListener

public void processListener(FacesListener listener)

Description copied from class: FacesEvent

Broadcast this FacesEvent to the specified FacesListener, by whatever mechanism is appropriate. Typically, this will be accomplished by calling an event processing method, and passing this FacesEvent as a paramter.

Specified by:

processListener in class FacesEvent

Parameters:

listener - FacesListener to send this FacesEvent to

Throws:

AbortProcessingException - Signal the Jakarta Faces implementation that no further processing on the current event should be performed