/*

  * 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.render;

 import java.io.IOException;

 import javax.faces.component.UIComponent;

 import javax.faces.context.FacesContext;

 import javax.faces.convert.ConverterException;

 /**

  * see Javadoc of <a href="http://java.sun.com/javaee/javaserverfaces/1.2/docs/api/index.html">JSF Specification</a>

  * 

  * @author Manfred Geiler (latest modification by $Author: slessard $)

  * @version $Revision: 701829 $ $Date: 2008-10-05 12:06:02 -0500 (Sun, 05 Oct 2008) $

  */

 public abstract class Renderer

 {

     public void decode(FacesContext context, UIComponent component)

     {

         if (context == null)

             throw new NullPointerException("context");

         if (component == null)

             throw new NullPointerException("component");

     }

     /**

      * @throws IOException if an input/output error occurs while rendering 

      */

     public void encodeBegin(FacesContext context, UIComponent component) throws IOException

     {

         if (context == null)

             throw new NullPointerException("context");

         if (component == null)

             throw new NullPointerException("component");

     }

     /**

      * Render all children if there are any.

      * 

      * Note: this will only be called if getRendersChildren() returns true. A component which has a renderer with

      * getRendersChildren() set to true will typically contain the rendering logic for its children in this method.

      * 

      * @param context

      * @param component

      * @throws IOException

      */

     public void encodeChildren(FacesContext context, UIComponent component) throws IOException

     {

         if (context == null)

             throw new NullPointerException("context");

         if (component == null)

             throw new NullPointerException("component");

         if (component.getChildCount() > 0)

         {

             for (UIComponent child : component.getChildren())

             {

                 if (!child.isRendered())

                 {

                     continue;

                 }

                 child.encodeAll(context);

             }

         }

     }

     /**

      * @throws IOException if an input/output error occurs while rendering 

      */

     public void encodeEnd(FacesContext context, UIComponent component) throws IOException

     {

         if (context == null)

             throw new NullPointerException("context");

         if (component == null)

             throw new NullPointerException("component");

     }

     public String convertClientId(FacesContext context, String clientId)

     {

         if (context == null)

             throw new NullPointerException("context");

         if (clientId == null)

             throw new NullPointerException("clientId");

         return clientId;

     }

     /**

      * Switch for deciding who renders the children.

      * 

      * @return <b>true</b> - if the component takes care of rendering its children. In this case, encodeChildren() ought

      *         to be called by the rendering controller (e.g., the rendering controller could be the method encodeAll()

      *         in UIComponent). In the method encodeChildren(), the component should therefore provide all children

      *         encode logic. <br/> <b>false</b> - if the component does not take care of rendering its children. In this

      *         case, encodeChildren() should not be called by the rendering controller. Instead, the children-list

      *         should be retrieved and the children should directly be rendered by the rendering controller one by one.

      */

     public boolean getRendersChildren()

     {

         return false;

     }

     public Object getConvertedValue(FacesContext context, UIComponent component, Object submittedValue)

         throws ConverterException

     {

         if (context == null)

             throw new NullPointerException("context");

         if (component == null)

             throw new NullPointerException("component");

         return submittedValue;

     }

 }