/*

  * $Source$

  * $Revision$

  *

  * Copyright (C) 2005 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.webmacro;

 import org.melati.MelatiConfig;

 import org.melati.poem.AccessPoemException;

 import org.melati.template.AbstractTemplateEngine;

 import org.melati.template.NotFoundException;

 import org.melati.template.TemplateContext;

 import org.melati.template.TemplateEngine;

 import org.melati.template.TemplateEngineException;

 import org.melati.util.MelatiStringWriter;

 import org.melati.util.MelatiWriter;

 import org.webmacro.InitException;

 import org.webmacro.PropertyException;

 import org.webmacro.WM;

 import org.webmacro.Context;

 /**

  * Wrapper for the WebMacro Template Engine for use with Melati.

  */

 public class WebmacroTemplateEngine extends AbstractTemplateEngine implements TemplateEngine {

   /** The name of the engine. */

   public static final String NAME = "webmacro";

   /** The WebMacro. */

   public WM wm;

   //private WebContext _webContext;

   /**

    * Constructor.

    */

   public WebmacroTemplateEngine() {

     super();

   }

   /**

    * Construct a new Engine.

    *

    * @param melatiConfig a {@link MelatiConfig}

    * @throws TemplateEngineException if any problem occurs with the engine

    */

   public void init(MelatiConfig melatiConfig) 

       throws TemplateEngineException {

     try {

       wm = new WM ();

     } catch (InitException e) {

       throw new TemplateEngineException(e);

     }

   }

   /**

    * Create a new, empty, Context for WebMacro.

    *

    * @return a {@link TemplateContext}

    */

   public TemplateContext getTemplateContext() {

     Context context = new Context(wm.getBroker());

     return new WebmacroTemplateContext(context);

   }

   /**

    * The name of the template engine (used to find the templets).

    * @return the name of the current configured template engine

    */

   public String getName () {

     return NAME;

   }

   /**

    * @return the extension of the templates used by 

    * WebMacro, including the dot. 

    * 

    */

   public String templateExtension() {

     return ".wm";

   }

   /** 

    * Get a template given it's name.

    * 

    * @param templateName the name of the template to find

    * @return a template

    * @throws NotFoundException if template not found

    */

   public org.melati.template.Template template(String templateName)

       throws NotFoundException {

     try {                                  

       org.webmacro.Template template = wm.getTemplate(templateName);

       return new WebmacroTemplate(template);

     } catch (org.webmacro.NotFoundException e) {

       throw new NotFoundException("Could not find template " + templateName);

     } catch (Exception e) {

       throw new TemplateEngineException(e);

     }

   }

   /** 

    * Expand the Template against the context.

    *

    * @param out             a {@link MelatiWriter} to output on

    * @param templateName    the name of the template to expand

    * @param templateContext the {@link TemplateContext} to expand 

    *                        the template against

    * @throws NotFoundException if template not found

    */

   public void expandTemplate(MelatiWriter out, 

                              String templateName, 

                              TemplateContext templateContext)

       throws NotFoundException {

     expandTemplate (out, template(templateName), templateContext);

   }

   /**

    * Expand the Template against the context.

    *

    * @param out             a {@link MelatiWriter} to output on

    * @param template        the {@link org.melati.template.Template} to expand

    * @param templateContext the {@link TemplateContext} to expand 

    *                        the template against

    */

   public void expandTemplate(MelatiWriter out,

                              org.melati.template.Template template, 

                              TemplateContext templateContext) {

     try {

       template.write(out, templateContext);

     } catch (TemplateEngineException problem) {

       // underlying will always be a PropertyException

       PropertyException underlying = (PropertyException)problem.subException;

       Throwable caught = underlying.getCause();

       if (caught instanceof AccessPoemException) {

         throw (AccessPoemException)caught;

       }

       throw problem;

     }

   }

   /**

    * {@inheritDoc}

    * @see org.melati.template.AbstractTemplateEngine#expandedTemplate

    */

   public String expandedTemplate(org.melati.template.Template template,  

                                  TemplateContext templateContext) {

       MelatiStringWriter s = new MelatiWebmacroStringWriter();

       expandTemplate(s, template, templateContext);

       return s.toString();

   }

   /** 

    * Return a {@link MelatiWebmacroStringWriter}.

    *

    * {@inheritDoc}

    * @see org.melati.Melati#getStringWriter() 

    * @see org.melati.template.AbstractTemplateEngine#getStringWriter()

    */

   public MelatiStringWriter getStringWriter() {

     return new MelatiWebmacroStringWriter();

   }

   /**

    * Get the underlying engine.

    *

    * @return the configured template engine

    */

   public Object getEngine() {

     return wm;

   }

 }