001/*
002 * (C) Copyright 2007 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     Nuxeo - initial API and implementation
018 *
019 * $Id: GenericHtmlComponentHandler.java 28610 2008-01-09 17:13:52Z sfermigier $
020 */
021
022package org.nuxeo.ecm.platform.ui.web.tag.handler;
023
024import javax.el.ValueExpression;
025import javax.faces.component.UIComponent;
026import javax.faces.component.ValueHolder;
027import javax.faces.view.facelets.ComponentConfig;
028import javax.faces.view.facelets.FaceletContext;
029
030import org.nuxeo.ecm.platform.ui.web.binding.DefaultValueExpression;
031
032import com.sun.faces.facelets.tag.jsf.html.HtmlComponentHandler;
033
034/**
035 * Generic HTML component handler.
036 * <p>
037 * Handler that manages a defaultValue attribute set on the tag, to default to this value when value is null or empty.
038 *
039 * @author <a href="mailto:at@nuxeo.com">Anahide Tchertchian</a>
040 */
041public class GenericHtmlComponentHandler extends HtmlComponentHandler {
042
043    public GenericHtmlComponentHandler(ComponentConfig config) {
044        super(config);
045    }
046
047    /**
048     * Overrides the "value" value expression to handle default value mapping.
049     */
050    public void onComponentCreated(FaceletContext ctx, UIComponent c, UIComponent parent) {
051        if (c instanceof ValueHolder) {
052            ValueExpression dve = c.getValueExpression("defaultValue");
053            if (dve != null) {
054                c.setValueExpression("value", new DefaultValueExpression(c.getValueExpression("value"), dve));
055            }
056        }
057    }
058
059}