javax.faces.view.facelets.MetaRule Maven / Gradle / Ivy
Show all versions of jakarta.faces-api Show documentation
/*
* Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
* Copyright 2005-2007 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package javax.faces.view.facelets;
/**
* The root class of the abstraction that dictates
* how attributes on a markup element in a Facelets VDL page are wired to the
* JSF API object instance associated with that element. The single method on
* this interface, {@link #applyRule}, 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.
*
*
*
*
* The first has an applyRule() method that returns a
* {@link Metadata} instance that, when its applyMetada() method is
* called, dictates how the "value" attribute is processed: calling {@link
* javax.faces.component.UIComponent#setValueExpression} on the
* UIComponent instance associated with the
* <h:inputText> element.
* The second has an applyRule() method that returns a
* {@link Metadata} instance that, when its applyMetadata() method
* is called, dictates how the "valueChangeListener" attribute is processed:
* calling {@link
* javax.faces.component.EditableValueHolder#addValueChangeListener}.
*
*
*
* @since 2.0
*/
public abstract class MetaRule {
/**
* 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.
*
* @param name the name for this rule. This will generally be the name of a
* tag attribute in the VDL.
* @param attribute the name/value pair for this attribute on this
* particular instance of an element in the page.
* @param meta the MetadataTarged that can be used to discern
* what kind of action to encapsulate within the abstraction to be returned.
* @return the {@link Metadata}.
* @since 2.0
*/
public abstract Metadata applyRule(String name, TagAttribute attribute,
MetadataTarget meta);
}