Class UICommand

java.lang.Object

jakarta.faces.component.UIComponent

jakarta.faces.component.UIComponentBase

jakarta.faces.component.UICommand

All Implemented Interfaces:

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

Direct Known Subclasses:

HtmlCommandButton, HtmlCommandLink, HtmlCommandScript

public class UICommand
extends UIComponentBase
implements ActionSource

UICommand is a UIComponent that represents a user interface component which, when activated by the user, triggers an application specific "command" or "action". Such a component is typically rendered as a push button, a menu item, or a hyperlink.

When the decode() method of this UICommand, or its corresponding Renderer, detects that this control has been activated, it will queue an ActionEvent. Later on, the broadcast() method will ensure that this event is broadcast to all interested listeners.

Listeners will be invoked in the following order:

1. ActionListeners, in the order in which they were registered.
2. The "actionListener" MethodExpression (which will cover the "actionListener" that was set as a MethodBinding).
3. The default ActionListener, retrieved from the Application - and therefore, any attached "action" MethodExpression.

By default, the rendererType property must be set to "jakarta.faces.Button". This value can be changed by calling the setRendererType() method.

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 UIComponent

ATTRS_WITH_DECLARED_DEFAULT_VALUES, BEANINFO_KEY, COMPOSITE_COMPONENT_TYPE_KEY, COMPOSITE_FACET_NAME, FACETS_KEY, VIEW_LOCATION_KEY

Modifier and Type	Field	Description
static final String	ATTRS_WITH_DECLARED_DEFAULT_VALUES	This constant enables one to quickly discover the names of the declared composite component attributes that have been given default values by the composite component author.
static final String	BEANINFO_KEY	The value of this constant is used as the key in the component attribute map, the value for which is a java.beans.BeanInfo implementation describing the composite component.
static final String	COMPOSITE_COMPONENT_TYPE_KEY	The value of this constant is used as the key in the composite component BeanDescriptor for a ValueExpression that evaluates to the component-type of the composite component root UIComponent for this composite component, if one was declared by the composite component author.
static final String	COMPOSITE_FACET_NAME	The value of this constant is used as the key in the Map returned as described in UIComponent.FACETS_KEY for the PropertyDescriptor describing the composite component facet.
static final String	FACETS_KEY	The value of this constant is used as the key in the composite component BeanDescriptor for the Map<PropertyDescriptor> that contains meta-information for the declared facets for this composite component.
static final String	VIEW_LOCATION_KEY	The value of this constant is used as the key in the component attributes Map for the Location in the view at which this component instance resides.

Constructor Summary

Constructors

Constructor	Description
UICommand()	Create a new UICommand 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)	In addition to to the default UIComponent.broadcast(FacesEvent) processing, pass the ActionEvent being broadcast to the method referenced by actionListener (if any), and to the default ActionListener registered on the Application.
jakarta.el.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.
Object	getValue()	Returns the value property of the UICommand.
boolean	isImmediate()	The immediate flag.
void	queueEvent(FacesEvent event)	Intercept queueEvent and take the following action.
void	removeActionListener(ActionListener listener)	Remove an existing ActionListener (if any) from the set of listeners interested in being notified when ActionEvents occur.
void	setActionExpression(jakarta.el.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	setValue(Object value)	Sets the value property of the UICommand.

Methods inherited from class UIComponentBase

addClientBehavior, addFacesListener, clearInitialState, decode, 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, isRendered, isTransient, markInitialState, processDecodes, processRestoreState, processSaveState, processUpdates, processValidators, removeFacesListener, restoreAttachedState, restoreState, saveAttachedState, saveState, setId, setParent, setRendered, setRendererType, setTransient, subscribeToEvent, unsubscribeFromEvent

Modifier and Type	Method	Description
void	addClientBehavior(String eventName, ClientBehavior behavior)	This is a default implementation of ClientBehaviorHolder.addClientBehavior(String, ClientBehavior).
protected void	addFacesListener(FacesListener listener)	Add the specified FacesListener to the set of listeners registered to receive event notifications from this UIComponent.
void	clearInitialState()	For each of the attached objects on this instance that implement PartialStateHolder, call PartialStateHolder.clearInitialState() on the attached object.
void	decode(FacesContext context)	Decode any new state of this UIComponent from the request contained in the specified FacesContext, and store this state as needed.
void	encodeBegin(FacesContext context)	If our rendered property is true, render the beginning of the current state of this UIComponent to the response contained in the specified FacesContext.
void	encodeChildren(FacesContext context)	If our rendered property is true, render the child UIComponents of this UIComponent.
void	encodeEnd(FacesContext context)	If our rendered property is true, render the ending of the current state of this UIComponent.
UIComponent	findComponent(String expression)	Search for and return the UIComponent with an id that matches the specified search expression (if any), according to the algorithm described below.
Map<String,Object>	getAttributes()	Return a mutable Map representing the attributes (and properties, see below) associated wth this UIComponent, keyed by attribute name (which must be a String).
int	getChildCount()	Return the number of child UIComponents that are associated with this UIComponent.
List<UIComponent>	getChildren()	Return a mutable List representing the child UIComponents associated with this component.
Map<String, List<ClientBehavior>>	getClientBehaviors()	This is a default implementation of ClientBehaviorHolder.getClientBehaviors().
String	getClientId(FacesContext context)	Return a client-side identifier for this component, generating one if necessary.
String	getDefaultEventName()	This is a default implementation of ClientBehaviorHolder.getDefaultEventName().
Collection<String>	getEventNames()	This is a default implementation of ClientBehaviorHolder.getEventNames().
protected FacesContext	getFacesContext()	Convenience method to return the FacesContext instance for the current request.
protected FacesListener[]	getFacesListeners(Class clazz)	Return an array of registered FacesListeners that are instances of the specified class.
UIComponent	getFacet(String name)	Convenience method to return the named facet, if it exists, or null otherwise.
int	getFacetCount()	Return the number of facet UIComponents that are associated with this UIComponent.
Map<String, UIComponent>	getFacets()	Return a mutable Map representing the facet UIComponents associated with this UIComponent, keyed by facet name (which must be a String).
Iterator<UIComponent>	getFacetsAndChildren()	Return an Iterator over the facet followed by child UIComponents of this UIComponent.
String	getId()	Return the component identifier of this UIComponent.
List<SystemEventListener>	getListenersForEventClass(Class<? extends SystemEvent> eventClass)	Return the SystemEventListener instances registered on this UIComponent instance that are interested in events of type eventClass.
UIComponent	getParent()	Return the parent UIComponent of this UIComponent, if any.
Map<String,Object>	getPassThroughAttributes(boolean create)	This method has the same specification as UIComponent.getPassThroughAttributes() except that it is allowed to return null if and only if the argument create is false and no pass through attribute data structure exists for this instance.
protected Renderer	getRenderer(FacesContext context)	Convenience method to return the Renderer instance associated with this component, if any; otherwise, return null.
String	getRendererType()	Return the Renderer type for this UIComponent (if any).
boolean	getRendersChildren()	Return a flag indicating whether this component is responsible for rendering its child components.
boolean	invokeOnComponent(FacesContext context, String clientId, ContextCallback callback)	Starting at this component in the View hierarchy, search for a component with a clientId equal to the argument clientId and, if found, call the ContextCallback.invokeContextCallback(FacesContext, UIComponent) method on the argument callback, passing the current FacesContext and the found component as arguments.
boolean	isRendered()	Return true if this component (and its children) should be rendered during the Render Response phase of the request processing lifecycle.
boolean	isTransient()	If true, the Object implementing this interface must not participate in state saving or restoring.
void	markInitialState()	For each of the attached objects on this instance that implement PartialStateHolder, call PartialStateHolder.markInitialState() on the attached object.
void	processDecodes(FacesContext context)	Perform the component tree processing required by the Apply Request Values phase of the request processing lifecycle for all facets of this component, all children of this component, and this component itself, as follows.
void	processRestoreState(FacesContext context, Object state)	Perform the component tree processing required by the Restore View phase of the request processing lifecycle for all facets of this component, all children of this component, and this component itself, as follows.
Object	processSaveState(FacesContext context)	Perform the component tree processing required by the state saving portion of the Render Response phase of the request processing lifecycle for all facets of this component, all children of this component, and this component itself, as follows.
void	processUpdates(FacesContext context)	Perform the component tree processing required by the Update Model Values phase of the request processing lifecycle for all facets of this component, all children of this component, and this component itself, as follows.
void	processValidators(FacesContext context)	Perform the component tree processing required by the Process Validations phase of the request processing lifecycle for all facets of this component, all children of this component, and this component itself, as follows.
protected void	removeFacesListener(FacesListener listener)	Remove the specified FacesListener from the set of listeners registered to receive event notifications from this UIComponent.
static Object	restoreAttachedState(FacesContext context, Object stateObj)	This method is called by UIComponent subclasses that need to restore the objects they saved using UIComponentBase.saveAttachedState(FacesContext, Object).
void	restoreState(FacesContext context, Object state)	Perform any processing required to restore the state from the entries in the state Object.
static Object	saveAttachedState(FacesContext context, Object attachedObject)	This method is called by UIComponent subclasses that want to save one or more attached objects.
Object	saveState(FacesContext context)	Gets the state of the instance as a Serializable Object.
void	setId(String id)	Set the component identifier of this UIComponent (if any).
void	setParent(UIComponent parent)	Set the parent UIComponent of this UIComponent.
void	setRendered(boolean rendered)	Set the rendered property of this UIComponent.
void	setRendererType(String rendererType)	Set the Renderer type for this UIComponent, or null for components that render themselves.
void	setTransient(boolean transientFlag)	Denotes whether or not the Object implementing this interface must or must not participate in state saving or restoring.
void	subscribeToEvent(Class<? extends SystemEvent> eventClass, ComponentSystemEventListener componentListener)	Install the listener instance referenced by argument componentListener as a listener for events of type eventClass originating from this specific instance of UIComponent.
void	unsubscribeFromEvent(Class<? extends SystemEvent> eventClass, ComponentSystemEventListener componentListener)	Remove the listener instance referenced by argument componentListener as a listener for events of type eventClass originating from this specific instance of UIComponent.

Methods inherited from class UIComponent

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

Modifier and Type	Method	Description
void	encodeAll(FacesContext context)	If this component returns true from UIComponent.isRendered(), take the following action.
String	getClientId()	Enable Jakarta Expression Language to access the clientId of a component.
static UIComponent	getCompositeComponentParent(UIComponent component)	Finds the nearest composite component parent of the specified component.
String	getContainerClientId(FacesContext context)	Allow components that implement NamingContainer to selectively disable prepending their clientId to their descendent's clientIds by breaking the prepending logic into a separately callable method.
static UIComponent	getCurrentComponent(FacesContext context)	Return the UIComponent instance that is currently processing.
static UIComponent	getCurrentCompositeComponent(FacesContext context)	Return the closest ancestor component, relative to the component returned from UIComponent.getCurrentComponent(FacesContext), that is a composite component, or null if no such component exists.
UIComponent	getFacet(Enum<?> identifier)	Convenience method to return the named facet using an enum identifier, if it exists, or null otherwise.
UIComponent	getNamingContainer()	Starting with "this", return the closest component in the ancestry that is a NamingContainer or null if none can be found.
Map<String,Object>	getPassThroughAttributes()	This is a convenience method that simply calls UIComponent.getPassThroughAttributes(boolean), passing true as the argument.
Map<String,String>	getResourceBundleMap()	Return a Map<String,String> of the ResourceBundle for this component.
protected StateHelper	getStateHelper()	Return the StateHelper instance used to help this component implement PartialStateHolder.
protected StateHelper	getStateHelper(boolean create)	Like UIComponent.getStateHelper(), but only create a state helper instance if the argument creat is true.
TransientStateHelper	getTransientStateHelper()	Return the TransientStateHelper instance for this UIComponent instance.
TransientStateHelper	getTransientStateHelper(boolean create)	Return the TransientStateHelper instance for this UIComponent instance.
jakarta.el.ValueExpression	getValueExpression(String name)	Return the ValueExpression used to calculate the value for the specified attribute or property name, if any.
boolean	initialStateMarked()	An implementation of PartialStateHolder.initialStateMarked(), this method is called by the runtime to test if the PartialStateHolder.markInitialState() method was called.
static boolean	isCompositeComponent(UIComponent component)	Return true if component is a composite component, otherwise false.
boolean	isInView()	Return true if this component is within the view hierarchy otherwise false
protected boolean	isVisitable(VisitContext context)	Return true if this component should be visited, false otherwise.
void	popComponentFromEL(FacesContext context)	Pop the current UIComponent from the FacesContext attributes map so that the previous UIComponent, if any, becomes the current component.
void	processEvent(ComponentSystemEvent event)	The default implementation performs the following action.
void	pushComponentToEL(FacesContext context, UIComponent component)	Push the current UIComponent this to the FacesContext attribute map saving the previous UIComponent for a subsequent call to UIComponent.popComponentFromEL(FacesContext).
void	restoreTransientState(FacesContext context, Object state)	For components that need to support the concept of transient state, this method will restore any state saved on a prior call to UIComponent.saveTransientState(FacesContext).
Object	saveTransientState(FacesContext context)	For components that need to support the concept of transient state, this method will save any state that is known to be transient in nature.
void	setInView(boolean isInView)	Updates the status as to whether or not this component is currently within the view hierarchy.
void	setValueExpression(String name, jakarta.el.ValueExpression binding)	Set the ValueExpression used to calculate the value for the specified attribute or property name, if any.
boolean	visitTree(VisitContext visitContext, VisitCallback callback)	Perform a tree visit starting at this node in the tree.

Methods inherited from class 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

UICommand

public UICommand()

Create a new UICommand 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()

The immediate flag.

Specified by:

isImmediate in interface ActionSource

Returns:

true if immediate, false otherwise.

setImmediate

public void setImmediate(boolean immediate)

Description copied from interface: ActionSource

Set the "immediate execution" flag for this UIComponent.

Specified by:

setImmediate in interface ActionSource

Parameters:

immediate - The new immediate execution flag

getValue

public Object getValue()

Returns the value property of the UICommand. This is most often rendered as a label.

Returns:

The object representing the value of this component.

setValue

public void setValue(Object value)

Sets the value property of the UICommand. This is most often rendered as a label.

Parameters:

value - the new value

getActionExpression

public jakarta.el.MethodExpression getActionExpression()

Description copied from interface: ActionSource

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.

setActionExpression

public void setActionExpression(jakarta.el.MethodExpression actionExpression)

Description copied from interface: ActionSource

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 new method expression

addActionListener

public void addActionListener(ActionListener listener)

Description copied from interface: ActionSource

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

Throws:

NullPointerException - if listener is null

getActionListeners

public ActionListener[] getActionListeners()

Description copied from interface: ActionSource

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.

removeActionListener

public void removeActionListener(ActionListener listener)

Description copied from interface: ActionSource

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

Throws:

NullPointerException - if listener is null

broadcast

public void broadcast(FacesEvent event)
               throws AbortProcessingException

In addition to to the default UIComponent.broadcast(FacesEvent) processing, pass the ActionEvent being broadcast to the method referenced by actionListener (if any), and to the default ActionListener registered on the Application.

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

queueEvent

public void queueEvent(FacesEvent event)

Intercept queueEvent and take the following action. If the event is an ActionEvent, obtain the UIComponent instance from the event. If the component is an ActionSource obtain the value of its "immediate" property. If it is true, mark the phaseId for the event to be PhaseId.APPLY_REQUEST_VALUES otherwise, mark the phaseId to be PhaseId.INVOKE_APPLICATION. The event must be passed on to super.queueEvent() before returning from this method.

Overrides:

queueEvent in class UIComponentBase

Parameters:

event - FacesEvent to be queued