DefaultPage.java
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.lang3.StringUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
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 $Id$
*/
public class DefaultPage implements Page
{
/** Logging */
protected final Logger log = LogManager.getLogger(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 = pipelineData.getRunData();
// 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
}
}