package org.apache.turbine.util.template;

 import org.apache.logging.log4j.LogManager;

 /*

  * 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 org.apache.logging.log4j.Logger;

 import org.apache.turbine.modules.NavigationLoader;

 import org.apache.turbine.pipeline.PipelineData;

 import org.apache.turbine.services.TurbineServices;

 import org.apache.turbine.services.template.TemplateService;

 /**

  * Returns output of a Navigation module.  An instance of this is

  * placed in the WebMacro context by the WebMacroSiteLayout.  This

  * allows template authors to set the navigation template they'd like

  * to place in their templates.  Here's how it's used in a

  * template:

  *

  * <p><code>

  * $navigation.setTemplate("admin_navigation.wm")

  * </code>

  *

  * @author <a href="mbryson@mont.mindspring.com">Dave Bryson</a>

  * @version $Id: TemplateNavigation.java 1854797 2019-03-04 20:41:39Z tv $

  */

 public class TemplateNavigation

 {

     /** Logging */

     private static final Logger log = LogManager.getLogger(TemplateNavigation.class);

     /* The PipelineData object. */

     private final PipelineData pipelineData;

     /* The name of the navigation template. */

     private String template = null;

     /**

      * Constructor

      *

      * @param pipelineData A Turbine PipelineData object.

      */

     public TemplateNavigation(PipelineData pipelineData)

     {

         this.pipelineData = pipelineData;

     }

     /**

      * Set the template.

      *

      * @param template A String with the name of the navigation

      * template.

      * @return A TemplateNavigation (self).

      */

     public TemplateNavigation setTemplate(String template)

     {

         log.debug("setTemplate({})", template);

         this.template = template;

         return this;

     }

     /**

      * Builds the output of the navigation template.

      *

      * @return A String.

      */

     @Override

     public String toString()

     {

         String module = null;

         String returnValue = null;

         try

         {

             if (template == null)

             {

                 returnValue = "Navigation Template is null (Might be unset)";

                 throw new Exception(returnValue);

             }

             pipelineData.getRunData().getTemplateInfo().setNavigationTemplate(template);

             TemplateService templateService = (TemplateService)TurbineServices.getInstance()

                     .getService(TemplateService.SERVICE_NAME);

             module = templateService.getNavigationName(template);

             if (module == null)

             {

                 returnValue = "Template Service returned null for Navigation Template " + template;

                 throw new Exception(returnValue);

             }

             returnValue = NavigationLoader.getInstance().eval(pipelineData, module);

         }

         catch (Exception e)

         {

             if (returnValue == null)

             {

                 returnValue = "Error processing navigation template: "

                         + template + ", using module: " + module;

             }

             log.error(returnValue, e);

         }

         return returnValue;

     }

 }