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.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.apache.turbine.annotation.TurbineLoader;

 import org.apache.turbine.annotation.TurbineService;

 import org.apache.turbine.modules.Screen;

 import org.apache.turbine.modules.ScreenLoader;

 import org.apache.turbine.pipeline.PipelineData;

 import org.apache.turbine.services.TurbineServices;

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

 import org.apache.turbine.util.RunData;

 import org.apache.turbine.util.template.TemplateInfo;

 /**

  * Template Screen.

  *

  * Base Template Screens should extend this class and override the

  * buildTemplate() method.  Users of the particular service can then

  * override the doBuildTemplate() for any specific pre-processing.

  * You can also override the doBuild() method in order to add extra

  * functionality to your system, but you need to make sure to at least

  * duplicate the existing functionality in order for things to work.

  * Look at the code for the doBuild() method to get an idea of what is

  * going on there (it is quite simple really).

  *

  * @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: TemplateScreen.java 1773378 2016-12-09 13:19:59Z tv $

  */

 public abstract class TemplateScreen

     extends Screen

 {

     /** Logging */

     protected Log log = LogFactory.getLog(this.getClass());

     /** Injected service instance */

     @TurbineService

     private TemplateService templateService;

     /** Injected loader instance */

     @TurbineLoader( Screen.class )

     private ScreenLoader screenLoader;

     /**

      * This method should be overridden by subclasses that wish to add

      * specific business logic.

      * @param pipelineData Turbine information.

      * @throws Exception A generic exception.

      */

     protected abstract void doBuildTemplate(PipelineData pipelineData)

             throws Exception;

     /**

      * This method should be implemented by Base template classes.  It

      * should contain the specific template service code to generate

      * the template.

      * @param pipelineData Turbine information.

      * @return the content of the screen

      * @throws Exception A generic exception.

      */

     public abstract String buildTemplate(PipelineData pipelineData)

             throws Exception;

     /**

      * This method can be overridden to write code that executes when

      * the template has been built (called from a finally clause, so

      * executes regardless of whether an exception is thrown or not)

      *

      * @param pipelineData Turbine information

      */

     protected void doPostBuildTemplate(PipelineData pipelineData)

     {

         // empty

     }

     /**

      * This method is called by the Screenloader to construct the

      * Screen.

      *

      * @param pipelineData Turbine information.

      * @return the content of the screen

      * @throws Exception A generic exception.

      */

     @Override

     protected String doBuild(PipelineData pipelineData)

             throws Exception

     {

         String out = null;

         try

         {

             doBuildTemplate(pipelineData);

             out = buildTemplate(pipelineData);

         }

         finally

         {

             doPostBuildTemplate(pipelineData);

         }

         return out;

     }

     /**

      * This method is used when you want to short circuit a Screen and

      * change the template that will be executed next. <b>Note that the current

      * context will be applied to the next template that is executed.

      * If you want to have the context executed for the next screen,

      * to be the same one as the next screen, then you should use the

      * TemplateScreen.doRedirect() method.</b>

      *

      * @param pipelineData Turbine information.

      * @param template The name of the next template.

      */

     public static void setTemplate(PipelineData pipelineData, String template)

     {

         RunData data = (RunData)pipelineData;

         TemplateInfo ti = data.getTemplateInfo();

         TemplateService templateService = (TemplateService)TurbineServices.getInstance().getService(TemplateService.SERVICE_NAME);

         ti.setScreenTemplate(template);

         try

         {

             // We have do call getScreenTemplate because of the path

             // separator.

             ti.setLayoutTemplate(templateService.getLayoutTemplateName(ti.getScreenTemplate()));

         }

         catch (Exception e)

         {

             // Nothing to do.

         }

     }

     /**

      * You can call this within a Screen to cause an internal redirect

      * to happen.  It essentially allows you to stop execution in one

      * Screen and instantly execute another Screen.  Don't worry, this

      * does not do a HTTP redirect and also if you have anything added

      * in the Context, it will get carried over.

      *

      * <p>

      *

      * This class is useful if you have a Screen that submits to

      * another Screen and you want it to do error validation before

      * executing the other Screen.  If there is an error, you can

      * doRedirect() back to the original Screen.

      *

      * @param pipelineData Turbine information.

      * @param screen Name of screen to redirect to.

      * @param template Name of template.

      * @throws Exception A generic exception.

      */

     public void doRedirect(PipelineData pipelineData, String screen, String template)

             throws Exception

     {

         log.debug("doRedirect(data, " + screen + ", " + template + ")");

         setTemplate(pipelineData, template);

         screenLoader.exec(pipelineData, screen);

     }

     /**

      * You can call this within a Screen to cause an internal redirect

      * to happen.  It essentially allows you to stop execution in one

      * Screen and instantly execute another Screen.  Don't worry, this

      * does not do a HTTP redirect and also if you have anything added

      * in the Context, it will get carried over.

      *

      * <p>

      *

      * This class is useful if you have a Screen that submits to

      * another Screen and you want it to do error validation before

      * executing the other Screen.  If there is an error, you can

      * doRedirect() back to the original Screen.

      *

      * @param pipelineData Turbine information.

      * @param template Name of template.

      * @throws Exception A generic exception.

      */

     public void doRedirect(PipelineData pipelineData, String template)

             throws Exception

     {

         doRedirect(pipelineData, templateService.getScreenName(template), template);

     }

 }