package org.apache.turbine.services.template.mapper;
   
   /*
    * 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.
   */
  
  import java.util.List;
  import java.util.ArrayList;
  import java.util.Arrays;
  
  import org.apache.commons.lang.StringUtils;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import org.apache.turbine.services.template.TemplateEngineService;
  import org.apache.turbine.services.template.TemplateService;
  import org.apache.turbine.services.template.TurbineTemplate;
  
  /***
   * This mapper is responsible for the lookup of templates for the Layout
   * It tries to look in various packages for a match:
   *
   * 1. about,directions,Driving.vm      <- exact match
   * 2. about,directions,Default.vm      <- package match, Default name
   * 3. about,Default.vm                 <- stepping up in the hierarchy
   * 4. Default.vm                       <- The name configured as default.layout.template
   *                                        in the corresponding Templating Engine
  
   *
   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
   * @version $Id: LayoutTemplateMapper.java 534527 2007-05-02 16:10:59Z tv $
   */
  
  public class LayoutTemplateMapper
      extends BaseTemplateMapper
      implements Mapper
  {
      /*** Logging */
      private static Log log = LogFactory.getLog(LayoutTemplateMapper.class);
  
      /***
       * Default C'tor. If you use this C'tor, you must use
       * the bean setter to set the various properties needed for
       * this mapper before first usage.
       */
      public LayoutTemplateMapper()
      {
      }
  
      /***
       * Look for a given Template, then try the
       * defaults until we hit the root.
       *
       * @param template The template name.
       * @return The parsed module name.
       */
      public String doMapping(String template)
      {
          log.debug("doMapping(" + template + ")");
          // Copy our elements into an array
          List components
              = new ArrayList(Arrays.asList(StringUtils.split(
                                                template,
                                                String.valueOf(TemplateService.TEMPLATE_PARTS_SEPARATOR))));
          int componentSize = components.size() - 1 ;
  
          // This method never gets an empty string passed.
          // So this is never < 0
          String templateName = (String) components.get(componentSize);
          components.remove(componentSize--);
  
          log.debug("templateName is " + templateName);
  
          // Last element decides, which template Service to use...
          TemplateEngineService tes = TurbineTemplate.getTemplateEngineService(templateName);
  
          if (tes == null)
          {
              return null;
          }
  
          String defaultName =
              TurbineTemplate.getDefaultLayoutTemplateName(templateName); // We're, after all, a Layout Template Mapper...
 
         // This is an optimization. If the name we're looking for is
         // already the default name for the template, don't do a "first run"
         // which looks for an exact match.
         boolean firstRun = !templateName.equals(defaultName);
 
         for(;;)
         {
             String templatePackage = StringUtils.join(components.iterator(), String.valueOf(separator));
 
             log.debug("templatePackage is now: " + templatePackage);
 
             StringBuffer testName = new StringBuffer();
 
             if (!components.isEmpty())
             {
                 testName.append(templatePackage);
                 testName.append(separator);
             }
 
             testName.append((firstRun)
                 ? templateName
                 : defaultName);
 
             // But the Templating service must look for the name with prefix
             StringBuffer templatePath = new StringBuffer();
             if (StringUtils.isNotEmpty(prefix))
             {
                 templatePath.append(prefix);
                 templatePath.append(separator);
             }
             templatePath.append(testName);
 
             log.debug("Looking for " + templatePath);
 
             if (tes.templateExists(templatePath.toString()))
             {
                 log.debug("Found it, returning " + testName);
                 return testName.toString();
             }
 
             if (firstRun)
             {
                 firstRun = false;
             }
             else
             {
                 // We're no longer on the first Run (so we
                 // already tested the "Default" template)
                 // and the package is empty (we've hit the
                 // root. So we now break the endless loop.
                 if (components.isEmpty())
                 {
                     break; // for(;;)
                 }
                 // We still have components. Remove the
                 // last one and go through the loop again.
                 components.remove(componentSize--);
             }
         }
 
         log.debug("Returning default");
         return getDefaultName(template);
     }
 }