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1   /*
2    * $Source: /usr/cvsroot/melati/melati/src/main/java/org/melati/template/velocity/PassbackEvaluationExceptionHandler.java,v $
3    * $Revision: 1.2 $
4    *
5    * Copyright (C) 2008 Tim Pizey
6    *
7    * Part of Melati (http://melati.org), a framework for the rapid
8    * development of clean, maintainable web applications.
9    *
10   * Melati is free software; Permission is granted to copy, distribute
11   * and/or modify this software under the terms either:
12   *
13   * a) the GNU General Public License as published by the Free Software
14   *    Foundation; either version 2 of the License, or (at your option)
15   *    any later version,
16   *
17   *    or
18   *
19   * b) any version of the Melati Software License, as published
20   *    at http://melati.org
21   *
22   * You should have received a copy of the GNU General Public License and
23   * the Melati Software License along with this program;
24   * if not, write to the Free Software Foundation, Inc.,
25   * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA to obtain the
26   * GNU General Public License and visit http://melati.org to obtain the
27   * Melati Software License.
28   *
29   * Feel free to contact the Developers of Melati (http://melati.org),
30   * if you would like to work out a different arrangement than the options
31   * outlined here.  It is our intention to allow Melati to be used by as
32   * wide an audience as possible.
33   *
34   * This program is distributed in the hope that it will be useful,
35   * but WITHOUT ANY WARRANTY; without even the implied warranty of
36   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
37   * GNU General Public License for more details.
38   *
39   * Contact details for copyright holder:
40   *
41   *     Tim Pizey <timp At paneris.org>
42   *     http://paneris.org/~timp
43   */
44  
45  package org.melati.template.velocity;
46  
47  
48  import org.apache.velocity.VelocityContext;
49  import org.apache.velocity.app.event.MethodExceptionEventHandler;
50  import org.melati.template.MarkupLanguage;
51  import org.webmacro.PropertyException;
52  
53  /**
54   * @author timp
55   * @since  1 Apr 2008
56   *
57   */
58  public class PassbackEvaluationExceptionHandler 
59      extends PropagateEvaluationExceptionHandler 
60      implements MethodExceptionEventHandler {
61  
62    /** The webcontext. */    
63    private VelocityContext velContext;    
64  
65    /**
66     * Constructor.
67     */
68    public PassbackEvaluationExceptionHandler(VelocityContext vc) {
69      super();
70      velContext = vc;
71    }
72  
73    @SuppressWarnings("unchecked")
74    @Override
75    public Object methodException(Class claz, String method, Exception problem) throws Exception {
76      System.err.println(method + " " + problem);
77      MarkupLanguage ml = (MarkupLanguage)velContext.get("ml");
78      if (ml == null) throw new PropertyException(
79        "Error, to use the Passback Evaluation Exception Handler, you must " +
80        "place your MarkupLanguage in the context as $ml - " + 
81        method + ": " + problem, problem);
82      Throwable underlying = problem;
83      return ml.rendered(underlying);    
84    }
85  
86  
87  }