Module jakarta.faces

Package jakarta.faces.view.facelets

Class MetaRule

java.lang.Object

jakarta.faces.view.facelets.MetaRule

Direct Known Subclasses:

EditableValueHolderRule, MethodRule, RenderPropertyRule

public abstract class MetaRule
extends Object

The root class of the abstraction that dictates how attributes on a markup element in a Facelets VDL page are wired to the Jakarta Faces API object instance associated with that element. The single method on this interface, applyRule(java.lang.String, jakarta.faces.view.facelets.TagAttribute, jakarta.faces.view.facelets.MetadataTarget), returns an encapsulation of the behavior that actually does the work of handling the attribute and its value. There are implementations of specific concrete subclasses of this class for all the basic kinds of elements that appear in Facelets VDL pages: components, non-components, and attached objects.

For example, consider this markup:

 <h:inputText value="#{user.userid}"
 valueChangeListener="#{user.newUserId}" />
 

Two MetaRule instances are involved in this example.

1. The first has an applyRule() method that returns a Metadata instance that, when its applyMetada() method is called, dictates how the "value" attribute is processed: calling UIComponent.setValueExpression(java.lang.String, jakarta.el.ValueExpression) on the UIComponent instance associated with the <h:inputText> element.

2. The second has an applyRule() method that returns a Metadata instance that, when its applyMetadata() method is called, dictates how the "valueChangeListener" attribute is processed: calling EditableValueHolder.addValueChangeListener(jakarta.faces.event.ValueChangeListener).

Since:

2.0

Constructor Summary

Constructors

Constructor	Description
MetaRule()

Method Summary

Modifier and Type	Method	Description
abstract Metadata	applyRule(String name, TagAttribute attribute, MetadataTarget meta)	Return an abstraction that takes appropriate action given the kind of rule represented by the argument name, in the context of this particular concrete subclass of MetaRule.

Methods inherited from class java.lang.Object

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

Constructor Details

MetaRule

public MetaRule()

Method Details

applyRule

public abstract Metadata applyRule(String name,
 TagAttribute attribute,
 MetadataTarget meta)

Return an abstraction that takes appropriate action given the kind of rule represented by the argument name, in the context of this particular concrete subclass of MetaRule. The abstraction must encapsulate the value from the argument attribute.

Parameters:

name - the name for this rule. This will generally be the name of a tag attribute in the VDL.

attribute - the name/value pair for this attribute on this particular instance of an element in the page.

meta - the MetadataTarged that can be used to discern what kind of action to encapsulate within the abstraction to be returned.

Returns:

the Metadata.

Since:

2.0