jakarta.faces.view.facelets.MetaRule Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2020 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 jakarta.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 Jakarta Server Faces 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 jakarta.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 jakarta.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);
}