package org.apache.turbine.modules.screens;

 /*

  * 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.commons.lang3.StringUtils;

 import org.apache.commons.lang3.exception.ExceptionUtils;

 import org.apache.turbine.TurbineConstants;

 import org.apache.turbine.annotation.TurbineConfiguration;

 import org.apache.turbine.annotation.TurbineService;

 import org.apache.turbine.pipeline.PipelineData;

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

 import org.apache.turbine.services.velocity.VelocityService;

 import org.apache.turbine.util.RunData;

 import org.apache.velocity.context.Context;

 /**

  * Base Velocity Screen.  The buildTemplate() assumes the template

  * parameter has been set in the PipelineData object.  This provides the

  * ability to execute several templates from one Screen.

  *

  * <p>

  *

  * If you need more specific behavior in your application, extend this

  * class and override the doBuildTemplate() method.

  *

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

  * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>

  * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>

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

  */

 public class VelocityScreen

     extends TemplateScreen

 {

     /** The prefix for lookup up screen pages */

     protected static final String prefix = PREFIX + "/";

     /** Injected service instance */

     @TurbineService

     protected VelocityService velocity;

     /** Injected service instance */

     @TurbineService

     protected TemplateService templateService;

     @TurbineConfiguration( TurbineConstants.TEMPLATE_ERROR_KEY )

     protected String templateError = TurbineConstants.TEMPLATE_ERROR_VM;

     /**

      * Velocity Screens extending this class should override this

      * method to perform any particular business logic and add

      * information to the context.

      *

      * @param pipelineData Turbine information.

      * @param context Context for web pages.

      * @throws Exception a generic exception.

      */

     protected void doBuildTemplate(PipelineData pipelineData,

                                    Context context)

             throws Exception

     {

         // empty

     }

     /**

      * Needs to be implemented to make TemplateScreen like us.  The

      * actual method that you should override is the one with the

      * context in the parameter list.

      *

      * @param pipelineData Turbine information.

      * @throws Exception a generic exception.

      */

     @Override

     protected void doBuildTemplate(PipelineData pipelineData)

             throws Exception

     {

         doBuildTemplate(pipelineData, velocity.getContext(pipelineData));

     }

     /**

      * This builds the Velocity template.

      *

      * @param pipelineData Turbine information.

      * @return the content of the screen

      * @throws Exception a generic exception.

      */

     @Override

     public String buildTemplate(PipelineData pipelineData)

         throws Exception

     {

         RunData data = pipelineData.getRunData();

         String screenData = null;

         Context context = velocity.getContext(pipelineData);

         String screenTemplate = data.getTemplateInfo().getScreenTemplate();

         String templateName

             = templateService.getScreenTemplateName(screenTemplate);

         // The Template Service could not find the Screen

         if (StringUtils.isEmpty(templateName))

         {

             log.error("Screen " + screenTemplate + " not found!");

             throw new Exception("Could not find screen for " + screenTemplate);

         }

         try

         {

             // if a layout has been defined return the results, otherwise

             // send the results directly to the output stream.

             if (getLayout(pipelineData) == null)

             {

                 velocity.handleRequest(context,

                         prefix + templateName,

                         data.getResponse().getOutputStream());

             }

             else

             {

                 screenData =

                     velocity.handleRequest(context, prefix + templateName);

             }

         }

         catch (Exception e)

         {

             // If there is an error, build a $processingException and

             // attempt to call the error.vm template in the screens

             // directory.

             context.put (TurbineConstants.PROCESSING_EXCEPTION_PLACEHOLDER, e.toString());

             context.put (TurbineConstants.STACK_TRACE_PLACEHOLDER, ExceptionUtils.getStackTrace(e));

             screenData = velocity.handleRequest(context, prefix + templateError);

         }

         return screenData;

     }

 }