/*

  * $Source: /usr/cvsroot/melati/melati/src/main/java/org/melati/template/velocity/PassbackEvaluationExceptionHandler.java,v $

  * $Revision: 1.1 $

  *

  * Copyright (C) 2008 Tim Pizey

  *

  * Part of Melati (http://melati.org), a framework for the rapid

  * development of clean, maintainable web applications.

  *

  * Melati is free software; Permission is granted to copy, distribute

  * and/or modify this software under the terms either:

  *

  * a) the GNU General Public License as published by the Free Software

  *    Foundation; either version 2 of the License, or (at your option)

  *    any later version,

  *

  *    or

  *

  * b) any version of the Melati Software License, as published

  *    at http://melati.org

  *

  * You should have received a copy of the GNU General Public License and

  * the Melati Software License along with this program;

  * if not, write to the Free Software Foundation, Inc.,

  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the

  * GNU General Public License and visit http://melati.org to obtain the

  * Melati Software License.

  *

  * Feel free to contact the Developers of Melati (http://melati.org),

  * if you would like to work out a different arrangement than the options

  * outlined here.  It is our intention to allow Melati to be used by as

  * wide an audience as possible.

  *

  * This program is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

  * Contact details for copyright holder:

  *

  *     Tim Pizey <timp At paneris.org>

  *     http://paneris.org/~timp

  */

 package org.melati.template.velocity;

 import java.io.IOException;

 import org.apache.velocity.VelocityContext;

 import org.apache.velocity.app.event.MethodExceptionEventHandler;

 import org.melati.template.MarkupLanguage;

 import org.melati.template.TemplateEngineException;

 import org.webmacro.PropertyException;

 /**

  * @author timp

  * @since  1 Apr 2008

  *

  */

 public class PassbackEvaluationExceptionHandler 

     extends PropagateEvaluationExceptionHandler 

     implements MethodExceptionEventHandler {

   /** The webcontext. */    

   private VelocityContext velContext;    

   /**

    * Constructor.

    */

   public PassbackEvaluationExceptionHandler(VelocityContext vc) {

     super();

     velContext = vc;

   }

   public Object methodException(Class claz, String method, Exception problem) throws Exception {

     System.err.println(method + " " + problem);

     MarkupLanguage ml = (MarkupLanguage)velContext.get("ml");

     if (ml == null) throw new PropertyException(

       "Error, to use the Passback Evaluation Exception Handler, you must " +

       "place your MarkupLanguage in the context as $ml - " + 

       method + ": " + problem, problem);

     Throwable underlying = problem;

     try {

       return ml.rendered(underlying);

     } catch (IOException e) {

       throw new TemplateEngineException(

         "The exception failed to render " + 

         method + ": " + e, e);

     }

   }

 }