/*

  * 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;

 /**

  * @since 1.2

  */

 public abstract class ConverterELTag extends TagSupport

 {

     private static final long serialVersionUID = -616834506829108081L;

     @Override

     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;

 }