package org.apache.turbine.modules.pages;

 /*

  * 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.lang.StringUtils;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.apache.turbine.annotation.TurbineLoader;

 import org.apache.turbine.modules.Action;

 import org.apache.turbine.modules.ActionLoader;

 import org.apache.turbine.modules.Layout;

 import org.apache.turbine.modules.LayoutLoader;

 import org.apache.turbine.modules.Page;

 import org.apache.turbine.modules.Screen;

 import org.apache.turbine.modules.ScreenLoader;

 import org.apache.turbine.pipeline.PipelineData;

 import org.apache.turbine.util.RunData;

 /**

  * When building sites using templates, Screens need only be defined

  * for templates which require dynamic (database or object) data.

  *

  * <p>

  *

  * This page can be used on sites where the number of Screens can be

  * much less than the number of templates.  The templates can be

  * grouped in directories with common layouts.  Screen modules are

  * then expected to be placed in packages corresponding with the

  * templates' directories and follow a specific naming scheme.

  *

  * <p>

  *

  * The template parameter is parsed and and a Screen whose package

  * matches the templates path and shares the same name minus any

  * extension and beginning with a capital letter is searched for.  If

  * not found, a Screen in a package matching the template's path with

  * name Default is searched for.  If still not found, a Screen with

  * name Default is looked for in packages corresponding to parent

  * directories in the template's path until a match is found.

  *

  * <p>

  *

  * For example if data.getParameters().getString("template") returns

  * /about_us/directions/driving.wm, the search follows

  * about_us.directions.Driving, about_us.directions.Default,

  * about_us.Default, Default, VelocitySiteScreen.

  *

  * <p>

  *

  * Only one Layout module is used, since it is expected that any

  * dynamic content will be placed in navigations and screens.  The

  * layout template to be used is found in a similar way to the Screen.

  * For example the following paths will be searched in the layouts

  * subdirectory: /about_us/directions/driving.wm,

  * /about_us/directions/default.wm, /about_us/default.wm, /default.wm.

  *

  * <p>

  *

  * This approach allows a site with largely static content to be

  * updated and added to regularly by those with little Java

  * experience.

  *

  * <p>

  *

  * The code is an almost a complete clone of the FreeMarkerSitePage

  * written by John McNally.  I've only modified it for Template use.

  *

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

  */

 public class DefaultPage

     extends Page

 {

     /** Logging */

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

     /** Injected loader instance */

     @TurbineLoader( Action.class )

     protected ActionLoader actionLoader;

     /** Injected loader instance */

     @TurbineLoader( Screen.class )

     protected ScreenLoader screenLoader;

     /** Injected loader instance */

     @TurbineLoader( Layout.class )

     protected LayoutLoader layoutLoader;

     /**

      * Builds the Page.

      *

      * @param pipelineData Turbine information.

      * @throws Exception a generic exception.

      */

     @Override

     public void doBuild(PipelineData pipelineData)

             throws Exception

     {

         RunData data = getRunData(pipelineData);

         // Template pages can use this to set up the context, so it is

         // available to the Action and Screen.  It does nothing here.

         doBuildBeforeAction(pipelineData);

         // If an action has been defined, execute it here.  Actions

         // can re-define the template definition.

         if (data.hasAction())

         {

             actionLoader.exec(pipelineData, data.getAction());

         }

         // if a redirect was setup in data, don't do anything else

         if (StringUtils.isNotEmpty(data.getRedirectURI()))

         {

             return;

         }

         // Template pages can use this to set up default templates and

         // associated class modules.  It does nothing here.

         doBuildAfterAction(pipelineData);

         String screenName = data.getScreen();

         log.debug("Building " + screenName);

         // Ask the Screen for its Layout and then execute the Layout.

         // The Screen can override the getLayout() method to re-define

         // the Layout depending on data passed in via the

         // data.parameters object.

         Screen aScreen = screenLoader.getAssembler(screenName);

         String layout = aScreen.getLayout(pipelineData);

         // If the Layout has been set to be null, attempt to execute

         // the Screen that has been defined.

         if (layout != null)

         {

             layoutLoader.exec(pipelineData, layout);

         }

         else

         {

             screenLoader.exec(pipelineData, screenName);

         }

         // Do any post build actions (overridable by subclasses -

         // does nothing here).

         doPostBuild(pipelineData);

     }

     /**

      * Can be used by template Pages to stuff the Context into the

      * PipelineData so that it is available to the Action module and the

      * Screen module via getContext().  It does nothing here.

      *

      * @param pipelineData Turbine information.

      * @throws Exception a generic exception.

      */

     protected void doBuildBeforeAction(PipelineData pipelineData)

             throws Exception

     {

         // do nothing by default

     }

     /**

      * Can be overridden by template Pages to set up data needed to

      * process a template.  It does nothing here.

      *

      * @param pipelineData Turbine information.

      * @throws Exception a generic exception.

      */

     protected void doBuildAfterAction(PipelineData pipelineData)

             throws Exception

     {

         // do nothing by default

     }

     /**

      * Can be overridden to perform actions when the request is

      * fully processed. It does nothing here.

      *

      * @param pipelineData Turbine information.

      * @throws Exception a generic exception.

      */

     protected void doPostBuild(PipelineData pipelineData)

             throws Exception

     {

         // do nothing by default

     }

 }