Module jakarta.faces

Package jakarta.faces.component

Class UIViewAction

java.lang.Object

jakarta.faces.component.UIComponent

jakarta.faces.component.UIComponentBase

jakarta.faces.component.UIViewAction

All Implemented Interfaces:

ActionSource, PartialStateHolder, StateHolder, TransientStateHolder, ComponentSystemEventListener, FacesListener, SystemEventListenerHolder, EventListener

public class UIViewAction
extends UIComponentBase
implements ActionSource

UIViewAction represents a method invocation that occurs during the request processing lifecycle, usually in response to an initial request, as opposed to a postback.

The ViewDeclarationLanguage implementation must cause an instance of this component to be placed in the view for each occurrence of an <f:viewAction /> element placed inside of an <f:metadata /> element. The user must place <f:metadata /> as a direct child of the UIViewRoot.

Because this class implements ActionSource, any actions that one would normally take on a component that implements ActionSource, such as UICommand, are valid for instances of this class. Instances of this class participate in the regular Jakarta Faces lifecycle, including on Ajax requests.

The purpose of this component is to provide a light-weight front-controller solution for executing code upon the loading of a Jakarta Faces view to support the integration of system services, content retrieval, view management, and navigation. This functionality is especially useful for non-faces (initial) requests.

The most common use case for this component is to take actions necessary for a particular view, often with the help of one or more UIViewParameters.

The NavigationHandler is consulted after the action is invoked to carry out the navigation case that matches the action signature and outcome. If a navigation case is matched that causes the new viewId to be different from the current viewId, the runtime must force a redirect to that matched navigation case with different viewId, regardless of whether or not the matched navigation case with different viewId called for a redirect. If the navigation will result in a flow transition, the appropriate metadata must be included in the query string for the redirect. See section 7.4.2 "Default NavigationHandler Algorithm" of the Jakarta Faces Specification Document, for the specification of how to handle <redirect /> cases.

It's important to note that the full component tree is not built before the UIViewAction components are processed on an non-faces (initial) request. Rather, the component tree only contains the ViewMetadata, an important part of the optimization of this component and what sets it apart from a PreRenderViewEvent listener.

Since:

2.2

Field Summary

Fields

Modifier and Type	Field	Description
static final String	COMPONENT_FAMILY	The standard component family for this component.
static final String	COMPONENT_TYPE	The standard component type for this component.

Fields inherited from class jakarta.faces.component.UIComponent

ATTRS_WITH_DECLARED_DEFAULT_VALUES, BEANINFO_KEY, COMPOSITE_COMPONENT_TYPE_KEY, COMPOSITE_FACET_NAME, FACETS_KEY, VIEW_LOCATION_KEY

Constructor Summary

Constructors

Constructor	Description
UIViewAction()	Create a new UIViewAction instance with default property values.

Method Summary

Modifier and Type	Method	Description
void	addActionListener(ActionListener listener)	Add a new ActionListener to the set of listeners interested in being notified when ActionEvents occur.
void	broadcast(FacesEvent event)	Enable the method invocation specified by this component instance to return a value that performs navigation, similar in spirit to UICommand.broadcast(jakarta.faces.event.FacesEvent).
void	decode(FacesContext context)	Override behavior from the superclass to queue an ActionEvent that may result in the invocation of the action or any actionListeners that may be associated with this instance.
MethodExpression	getActionExpression()	Return the MethodExpression pointing at the application action to be invoked, if this UIComponent is activated by the user, during the Apply Request Values or Invoke Application phase of the request processing lifecycle, depending on the value of the immediate property.
ActionListener[]	getActionListeners()	Return the set of registered ActionListeners for this ActionSource instance.
String	getFamily()	Return the identifier of the component family to which this component belongs.
String	getPhase()	Returns the name of the lifecycle phase in which the action is to be queued.
boolean	isImmediate()	If the value of the component's immediate attribute is true, the action will be invoked during the Apply Request Values Jakarta Faces lifecycle phase.
boolean	isOnPostback()	If true this component will operate on postback.
static boolean	isProcessingBroadcast(FacesContext context)	Returns true if the current request processing lifecycle is in the midst of processing the broadcast of an event queued during a call to decode(jakarta.faces.context.FacesContext).
boolean	isRendered()	Returns the if property of this component.
void	removeActionListener(ActionListener listener)	Remove an existing ActionListener (if any) from the set of listeners interested in being notified when ActionEvents occur.
void	setActionExpression(MethodExpression actionExpression)	Set the MethodExpression pointing at the appication action to be invoked, if this UIComponent is activated by the user, during the Apply Request Values or Invoke Application phase of the request processing lifecycle, depending on the value of the immediate property.
void	setImmediate(boolean immediate)	Set the "immediate execution" flag for this UIComponent.
void	setOnPostback(boolean onPostback)	Controls whether or not this component operates on postback.
void	setPhase(String phase)	Attempt to set the lifecycle phase in which this instance will queue its ActionEvent.
void	setRendered(boolean condition)	Sets the if property of this component.

Methods inherited from class jakarta.faces.component.UIComponentBase

addClientBehavior, addFacesListener, clearInitialState, encodeBegin, encodeChildren, encodeEnd, findComponent, getAttributes, getChildCount, getChildren, getClientBehaviors, getClientId, getDefaultEventName, getEventNames, getFacesContext, getFacesListeners, getFacet, getFacetCount, getFacets, getFacetsAndChildren, getId, getListenersForEventClass, getParent, getPassThroughAttributes, getRenderer, getRendererType, getRendersChildren, invokeOnComponent, isTransient, markInitialState, processDecodes, processRestoreState, processSaveState, processUpdates, processValidators, queueEvent, removeFacesListener, restoreAttachedState, restoreState, saveAttachedState, saveState, setId, setParent, setRendererType, setTransient, subscribeToEvent, unsubscribeFromEvent

Methods inherited from class jakarta.faces.component.UIComponent

encodeAll, getClientId, getCompositeComponentParent, getContainerClientId, getCurrentComponent, getCurrentCompositeComponent, getNamingContainer, getPassThroughAttributes, getResourceBundleMap, getStateHelper, getStateHelper, getTransientStateHelper, getTransientStateHelper, getValueExpression, initialStateMarked, isCompositeComponent, isInView, isVisitable, popComponentFromEL, processEvent, pushComponentToEL, restoreTransientState, saveTransientState, setInView, setValueExpression, visitTree

Methods inherited from class java.lang.Object

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

Field Details

COMPONENT_TYPE

public static final String COMPONENT_TYPE

The standard component type for this component.

See Also:

• Constant Field Values

COMPONENT_FAMILY

public static final String COMPONENT_FAMILY

The standard component family for this component.

See Also:

• Constant Field Values

Constructor Details

UIViewAction

public UIViewAction()

Create a new UIViewAction instance with default property values.

Method Details

getFamily

public String getFamily()

Description copied from class: UIComponent

Return the identifier of the component family to which this component belongs. This identifier, in conjunction with the value of the rendererType property, may be used to select the appropriate Renderer for this component instance. Note this method should NOT return null

Specified by:

getFamily in class UIComponent

Returns:

the component family (not null).

isImmediate

public boolean isImmediate()

If the value of the component's immediate attribute is true, the action will be invoked during the Apply Request Values Jakarta Faces lifecycle phase. Otherwise, the action will be invoked during the Invoke Application phase, the default behavior. The phase can be set explicitly in the phase attribute, which takes precedence over the immediate attribute.

Specified by:

isImmediate in interface ActionSource

Returns:

true if immediate, false otherwise.

Since:

2.2

setImmediate

public void setImmediate(boolean immediate)

Set the "immediate execution" flag for this UIComponent.

Specified by:

setImmediate in interface ActionSource

Parameters:

immediate - The new immediate execution flag

Since:

2.2

getPhase

public String getPhase()

Returns the name of the lifecycle phase in which the action is to be queued.

Returns:

the phase (as string).

Since:

2.2

setPhase

public void setPhase(String phase)

Attempt to set the lifecycle phase in which this instance will queue its ActionEvent. Pass the argument phase to PhaseId.phaseIdValueOf(java.lang.String). If the result is not one of the following values, FacesException must be thrown.

• PhaseId.APPLY_REQUEST_VALUES

• PhaseId.PROCESS_VALIDATIONS

• PhaseId.UPDATE_MODEL_VALUES

• PhaseId.INVOKE_APPLICATION

If set, this value takes precedence over the immediate flag.

Parameters:

phase - the phase id (as string value).

Since:

2.2

isProcessingBroadcast

public static boolean isProcessingBroadcast(FacesContext context)

Returns true if the current request processing lifecycle is in the midst of processing the broadcast of an event queued during a call to decode(jakarta.faces.context.FacesContext). The implementation of broadcast(jakarta.faces.event.FacesEvent) is responsible for ensuring that calls to this method accurately reflect this fact.

Parameters:

context - FacesContext for the current request

Returns:

true is currently processing broadcast, false otherwise.

Since:

2.2

addActionListener

public void addActionListener(ActionListener listener)

Add a new ActionListener to the set of listeners interested in being notified when ActionEvents occur.

Specified by:

addActionListener in interface ActionSource

Parameters:

listener - The ActionListener to be added

Since:

2.2

getActionListeners

public ActionListener[] getActionListeners()

Return the set of registered ActionListeners for this ActionSource instance. If there are no registered listeners, a zero-length array is returned.

Specified by:

getActionListeners in interface ActionSource

Returns:

the action listeners, or a zero-length array.

Since:

2.2

removeActionListener

public void removeActionListener(ActionListener listener)

Remove an existing ActionListener (if any) from the set of listeners interested in being notified when ActionEvents occur.

Specified by:

removeActionListener in interface ActionSource

Parameters:

listener - The ActionListener to be removed

Since:

2.2

getActionExpression

public MethodExpression getActionExpression()

Return the MethodExpression pointing at the application action to be invoked, if this UIComponent is activated by the user, during the Apply Request Values or Invoke Application phase of the request processing lifecycle, depending on the value of the immediate property.

The default implementation throws UnsupportedOperationException and is provided for the sole purpose of not breaking existing applications that extend ActionSource. Historically this method was declared in ActionSource2 for precisely this reason but default methods in interfaces weren't supported.

Specified by:

getActionExpression in interface ActionSource

Returns:

the action expression.

Since:

2.2

setActionExpression

public void setActionExpression(MethodExpression actionExpression)

Set the MethodExpression pointing at the appication action to be invoked, if this UIComponent is activated by the user, during the Apply Request Values or Invoke Application phase of the request processing lifecycle, depending on the value of the immediate property.

Any method referenced by such an expression must be public, with a return type of String, and accept no parameters.

The default implementation throws UnsupportedOperationException and is provided for the sole purpose of not breaking existing applications that extend ActionSource. Historically this method was declared in ActionSource2 for precisely this reason but default methods in interfaces weren't supported.

Specified by:

setActionExpression in interface ActionSource

Parameters:

actionExpression - the action expression.

Since:

2.2

isOnPostback

public boolean isOnPostback()

If true this component will operate on postback.

Returns:

true if operating upon postback, false otherwise.

Since:

2.2

setOnPostback

public void setOnPostback(boolean onPostback)

Controls whether or not this component operates on postback.

Parameters:

onPostback - the onPostback flag.

Since:

2.2

isRendered

public boolean isRendered()

Returns the if property of this component. If true then this component should take the actions specified in the decode(jakarta.faces.context.FacesContext) method.

Overrides:

isRendered in class UIComponentBase

Returns:

true if it should take the actions, false otherwise.

Since:

2.2

setRendered

public void setRendered(boolean condition)

Sets the if property of this component.

Overrides:

setRendered in class UIComponentBase

Parameters:

condition - the new value of the property.

Since:

2.2

broadcast

public void broadcast(FacesEvent event)
               throws AbortProcessingException

Enable the method invocation specified by this component instance to return a value that performs navigation, similar in spirit to UICommand.broadcast(jakarta.faces.event.FacesEvent).

Take no action and return immediately if any of the following conditions are true.

• The response has already been marked as complete.

• The current UIViewRoot is different from the event's source's UIViewRoot.

Save a local reference to the viewId of the current UIViewRoot. For discussion, let this reference be viewIdBeforeAction.

Obtain the ActionListener from the Application. Wrap the current FacesContext in an implementation of FacesContextWrapper that overrides the FacesContext.renderResponse() method such that it takes no action. Set the current FacesContext to be the FacesContextWrapper instance. Make it so a call to isProcessingBroadcast(jakarta.faces.context.FacesContext) on the current FacesContext will return true. This is necessary because the NavigationHandler will call this method to determine if the navigation is happening as the result of a UIViewAction. Invoke ActionListener.processAction(jakarta.faces.event.ActionEvent). In a finally block, restore the original FacesContext, make it so a call to isProcessingBroadcast(jakarta.faces.context.FacesContext) on the current context will return false and discard the wrapper.

If the response has been marked as complete during the invocation of processAction(), take no further action and return. Otherwise, compare viewIdBeforeAction with the viewId of the UIViewRoot on the FacesContext after the invocation of processAction(). If the two viewIds are the same and no more UIViewAction events have been queued by a call to decode(jakarta.faces.context.FacesContext), call FacesContext.renderResponse() and return. It is possible to detect the case where no more UIViewAction events have been queued because the number of such events queued has been noted in the specification for decode(jakarta.faces.context.FacesContext). Otherwise, execute the lifecycle on the new UIViewRoot.

Overrides:

broadcast in class UIComponentBase

Parameters:

event - FacesEvent to be broadcast

Throws:

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

IllegalArgumentException - if the implementation class of this FacesEvent is not supported by this component

NullPointerException - if event is null

Since:

2.2

decode

public void decode(FacesContext context)

Override behavior from the superclass to queue an ActionEvent that may result in the invocation of the action or any actionListeners that may be associated with this instance.

Take no action if any of the following conditions are true:

• The current request is a postback and the instance has been configured to not operate on postback. See isOnPostback().

• The condition stated in the if property evaluates to false. See isRendered()

  .

Instantiate an ActionEvent, passing this component instance as the source. Set the phaseId property of the ActionEvent as follows.

• If this component instance has been configured with a specific lifecycle phase with a call to setPhase(java.lang.String) use that as the phaseId

• If the value of the immediate property is true, use PhaseId.APPLY_REQUEST_VALUES.

• Otherwise, use PhaseId.INVOKE_APPLICATION.

Queue the event with a call to UIComponentBase.queueEvent(jakarta.faces.event.FacesEvent). Keep track of the number of events that are queued in this way on this run through the lifecycle. This information is necessary during processing in broadcast(jakarta.faces.event.FacesEvent).

Overrides:

decode in class UIComponentBase

Parameters:

context - FacesContext for the request we are processing

Since:

2.2