api/src/main/java/javax/faces/webapp/ConverterELTag.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.webapp;

import javax.faces.component.UIComponent;
import javax.faces.component.ValueHolder;
import javax.faces.convert.Converter;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.Tag;
import javax.servlet.jsp.tagext.TagSupport;

/**
 * @author Manfred Geiler (latest modification by $Author$)
 * @version $Revision$ $Date$
 *
 * @since 1.2
 */
public abstract class ConverterELTag
        extends TagSupport
{
    private static final long serialVersionUID = -616834506829108081L;

    public int doStartTag()
            throws JspException
    {
        UIComponentClassicTagBase componentTag = UIComponentELTag.getParentUIComponentClassicTagBase(pageContext);
        if (componentTag == null)
        {
            throw new JspException("no parent UIComponentTag found");
        }
        if (!componentTag.getCreated())
        {
            return Tag.SKIP_BODY;
        }

        UIComponent component = componentTag.getComponentInstance();
        if (component == null)
        {
            throw new JspException("parent UIComponentTag has no UIComponent");
        }
        if (!(component instanceof ValueHolder))
        {
            throw new JspException("UIComponent is no ValueHolder");
        }

        Converter converter = createConverter();

        ((ValueHolder)component).setConverter(converter);

        return Tag.SKIP_BODY;
    }

    protected abstract Converter createConverter()
            throws JspException;
}