org.omnifaces.eventlistener

Class ResetInputAjaxActionListener

java.lang.Object

org.omnifaces.eventlistener.DefaultPhaseListener

org.omnifaces.eventlistener.ResetInputAjaxActionListener

All Implemented Interfaces:

Serializable, EventListener, ActionListener, FacesListener, PhaseListener

public class ResetInputAjaxActionListener
extends DefaultPhaseListener
implements ActionListener

The ResetInputAjaxActionListener will reset input fields which are not executed during ajax submit, but which are rendered/updated during ajax response. This will prevent those input fields to remain in an invalidated state because of a validation failure during a previous request. This is very useful for cases where you need to update one form from another form by for example a modal dialog, or when you need a cancel/clear button.

How does it work? First, here are some JSF facts:

• When JSF validation succeeds for a particular input component during the validations phase, then the submitted value is set to null and the validated value is set as local value of the input component.
• When JSF validation fails for a particular input component during the validations phase, then the submitted value is kept in the input component.
• When at least one input component is invalid after the validations phase, then JSF will not update the model values for any of the input components. JSF will directly proceed to render response phase.
• When JSF renders input components, then it will first test if the submitted value is not null and then display it, else if the local value is not null and then display it, else it will display the model value.
• As long as you're interacting with the same JSF view, you're dealing with the same component state.

So, when the validation has failed for a particular form submit and you happen to need to update the values of input fields by a different ajax action or even a different ajax form (e.g. populating a field depending on a dropdown selection or the result of some modal dialog form, etc), then you basically need to reset the target input components in order to get JSF to display the model value which was edited during invoke action. Otherwise JSF will still display its local value as it was during the validation failure and keep them in an invalidated state.

The ResetInputAjaxActionListener is designed to solve exactly this problem. There are basically three ways to configure and use it:

• Register it as <phase-listener> in faces-config.xml. It'll be applied to every single ajax action throughout the webapp, on both UIInput and UICommand components.

   <lifecycle>
       <phase-listener>org.omnifaces.eventlistener.ResetInputAjaxActionListener</phase-listener>
   </lifecycle>
   

• Or register it as <action-listener> in faces-config.xml. It'll only be applied to ajax actions which are invoked by an UICommand component such as <h:commandButton> and <h:commandLink>.

   <application>
       <action-listener>org.omnifaces.eventlistener.ResetInputAjaxActionListener</action-listener>
   </application>
   

• Or register it as <f:actionListener> on the invidivual UICommand components where this action listener is absolutely necessary to solve the concrete problem. Note that it isn't possible to register it on the individual UIInput components using the standard JSF tags.

   <h:commandButton value="Update" action="#{bean.updateOtherInputs}">
       <f:ajax execute="currentInputs" render="otherInputs" />
       <f:actionListener type="org.omnifaces.eventlistener.ResetInputAjaxActionListener" />
   </h:commandButton>
   

This works with standard JSF, PrimeFaces and RichFaces actions. Only for RichFaces there's a reflection hack, because its ExtendedPartialViewContextImpl always returns an empty collection for render IDs. See also RF issue 11112.

Design notice: being a phase listener was mandatory in order to be able to hook on every single ajax action as standard JSF API does not (seem to?) offer any ways to register some kind of AjaxBehaviorListener in an application wide basis, let alone on a per <f:ajax> tag basis, so that it also get applied to ajax actions in UIInput components. There are ways with help of SystemEventListener, but it ended up to be too clumsy.

See also:
JSF spec issue 1060

Author:

Bauke Scholtz

See Also:

Serialized Form

Field Summary

Fields inherited from interface javax.faces.event.ActionListener

TO_FLOW_DOCUMENT_ID_ATTR_NAME

Constructor Summary

Constructors

Constructor and Description
ResetInputAjaxActionListener() Construct a new reset input ajax action listener.
ResetInputAjaxActionListener(ActionListener wrapped) Construct a new reset input ajax action listener around the given wrapped action listener.

Method Summary

Modifier and Type	Method and Description
void	beforePhase(PhaseEvent event) Delegate to the processAction(ActionEvent) method when this action listener is been registered as a phase listener so that it get applied on all ajax requests.
void	processAction(ActionEvent event) Handle the reset input action as follows, only and only if the current request is an ajax request and the PartialViewContext.getRenderIds() does not return an empty collection nor is the same as PartialViewContext.getExecuteIds(): find all EditableValueHolder components based on PartialViewContext.getRenderIds() and if the component is not covered by PartialViewContext.getExecuteIds(), then invoke EditableValueHolder.resetValue() on the component.

Methods inherited from class org.omnifaces.eventlistener.DefaultPhaseListener

afterPhase, getPhaseId

Methods inherited from class java.lang.Object

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

Constructor Detail

ResetInputAjaxActionListener

public ResetInputAjaxActionListener()

Construct a new reset input ajax action listener. This constructor will be used when specifying the action listener by <f:actionListener> or when registering as <phase-listener> in faces-config.xml.

ResetInputAjaxActionListener

public ResetInputAjaxActionListener(ActionListener wrapped)

Construct a new reset input ajax action listener around the given wrapped action listener. This constructor will be used when registering as <action-listener> in faces-config.xml.

Parameters:

wrapped - The wrapped action listener.

Method Detail

beforePhase

public void beforePhase(PhaseEvent event)

Delegate to the processAction(ActionEvent) method when this action listener is been registered as a phase listener so that it get applied on all ajax requests.

Specified by:

beforePhase in interface PhaseListener

Overrides:

beforePhase in class DefaultPhaseListener

See Also:

processAction(ActionEvent)

processAction

public void processAction(ActionEvent event)

Handle the reset input action as follows, only and only if the current request is an ajax request and the PartialViewContext.getRenderIds() does not return an empty collection nor is the same as PartialViewContext.getExecuteIds(): find all EditableValueHolder components based on PartialViewContext.getRenderIds() and if the component is not covered by PartialViewContext.getExecuteIds(), then invoke EditableValueHolder.resetValue() on the component.

Specified by:

processAction in interface ActionListener

Throws:

IllegalArgumentException - When one of the client IDs resolved to a null component. This would however indicate a bug in the concrete PartialViewContext implementation which is been used.