Java Reference
In-Depth Information
Whether you decide to have your component extend
UIComponentBase
or a standard
component, you might also want your component to implement one or more of these be-
havioral interfaces defined in the
javax.faces.component
package:
•
ActionSource
:
Indicates
that
the
component
can
fire
a
javax.faces.event.ActionEvent
.
•
ActionSource2
: Extends
ActionSource
and allows component properties
referencing methods that handle action events to use method expressions as
defined by the unified EL.
•
EditableValueHolder
: Extends
ValueHolder
and specifies additional
features for editable components, such as validation and emitting value-change
events.
•
NamingContainer
: Mandates that each component rooted at this component
have a unique ID.
•
StateHolder
: Denotes that a component has state that must be saved between
requests.
•
ValueHolder
: Indicates that the component maintains a local value as well as
the option of accessing data in the model tier.
If your component extends
UIComponentBase
, it automatically implements only
StateHolder
. Because all components directly or indirectly extend
UIComponen-
tBase
, they all implement
StateHolder
. Any component that implements
StateHolder
also implements the
StateHelper
interface, which extends
StateHolder
and defines a
Map
-like contract that makes it easy for components to
save and restore a partial view state.
If your component extends one of the other standard components, it might also implement
other behavioral interfaces in addition to
StateHolder
. If your component extends
UICommand
, it automatically implements
ActionSource2
. If your component ex-
tends
UIOutput
or one of the component classes that extend
UIOutput
, it automatic-
ally implements
ValueHolder
. If your component extends
UIInput
, it automatically
implements
EditableValueHolder
and
ValueHolder
. See the JavaServer Faces
API documentation to find out what the other component classes implement.
You can also make your component explicitly implement a behavioral interface that it
doesn't already by virtue of extending a particular standard component. For example, if
you have a component that extends
UIInput
and you want it to fire action events, you
must make it explicitly implement
ActionSource2
because a
UIInput
component
doesn't automatically implement this interface.
