    001package org.apache.turbine.modules.pages;
    002
    003
    004/*
    005 * Licensed to the Apache Software Foundation (ASF) under one
    006 * or more contributor license agreements.  See the NOTICE file
    007 * distributed with this work for additional information
    008 * regarding copyright ownership.  The ASF licenses this file
    009 * to you under the Apache License, Version 2.0 (the
    010 * "License"); you may not use this file except in compliance
    011 * with the License.  You may obtain a copy of the License at
    012 *
    013 *   http://www.apache.org/licenses/LICENSE-2.0
    014 *
    015 * Unless required by applicable law or agreed to in writing,
    016 * software distributed under the License is distributed on an
    017 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    018 * KIND, either express or implied.  See the License for the
    019 * specific language governing permissions and limitations
    020 * under the License.
    021 */
    022
    023
    024import org.apache.commons.lang.StringUtils;
    025import org.apache.commons.logging.Log;
    026import org.apache.commons.logging.LogFactory;
    027import org.apache.turbine.annotation.TurbineLoader;
    028import org.apache.turbine.modules.Action;
    029import org.apache.turbine.modules.ActionLoader;
    030import org.apache.turbine.modules.Layout;
    031import org.apache.turbine.modules.LayoutLoader;
    032import org.apache.turbine.modules.Page;
    033import org.apache.turbine.modules.Screen;
    034import org.apache.turbine.modules.ScreenLoader;
    035import org.apache.turbine.pipeline.PipelineData;
    036import org.apache.turbine.util.RunData;
    037
    038/**
    039 * When building sites using templates, Screens need only be defined
    040 * for templates which require dynamic (database or object) data.
    041 *
    042 * <p>
    043 *
    044 * This page can be used on sites where the number of Screens can be
    045 * much less than the number of templates.  The templates can be
    046 * grouped in directories with common layouts.  Screen modules are
    047 * then expected to be placed in packages corresponding with the
    048 * templates' directories and follow a specific naming scheme.
    049 *
    050 * <p>
    051 *
    052 * The template parameter is parsed and and a Screen whose package
    053 * matches the templates path and shares the same name minus any
    054 * extension and beginning with a capital letter is searched for.  If
    055 * not found, a Screen in a package matching the template's path with
    056 * name Default is searched for.  If still not found, a Screen with
    057 * name Default is looked for in packages corresponding to parent
    058 * directories in the template's path until a match is found.
    059 *
    060 * <p>
    061 *
    062 * For example if data.getParameters().getString("template") returns
    063 * /about_us/directions/driving.wm, the search follows
    064 * about_us.directions.Driving, about_us.directions.Default,
    065 * about_us.Default, Default, VelocitySiteScreen.
    066 *
    067 * <p>
    068 *
    069 * Only one Layout module is used, since it is expected that any
    070 * dynamic content will be placed in navigations and screens.  The
    071 * layout template to be used is found in a similar way to the Screen.
    072 * For example the following paths will be searched in the layouts
    073 * subdirectory: /about_us/directions/driving.wm,
    074 * /about_us/directions/default.wm, /about_us/default.wm, /default.wm.
    075 *
    076 * <p>
    077 *
    078 * This approach allows a site with largely static content to be
    079 * updated and added to regularly by those with little Java
    080 * experience.
    081 *
    082 * <p>
    083 *
    084 * The code is an almost a complete clone of the FreeMarkerSitePage
    085 * written by John McNally.  I've only modified it for Template use.
    086 *
    087 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
    088 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
    089 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
    090 * @version $Id: DefaultPage.java 1773378 2016-12-09 13:19:59Z tv $
    091 */
    092public class DefaultPage
    093    extends Page
    094{
    095    /** Logging */
    096    protected Log log = LogFactory.getLog(this.getClass());
    097
    098    /** Injected loader instance */
    099    @TurbineLoader( Action.class )
    100    protected ActionLoader actionLoader;
    101
    102    /** Injected loader instance */
    103    @TurbineLoader( Screen.class )
    104    protected ScreenLoader screenLoader;
    105
    106    /** Injected loader instance */
    107    @TurbineLoader( Layout.class )
    108    protected LayoutLoader layoutLoader;
    109
    110    /**
    111     * Builds the Page.
    112     *
    113     * @param pipelineData Turbine information.
    114     * @throws Exception a generic exception.
    115     */
    116    @Override
    117    public void doBuild(PipelineData pipelineData)
    118            throws Exception
    119    {
    120        RunData data = getRunData(pipelineData);
    121        // Template pages can use this to set up the context, so it is
    122        // available to the Action and Screen.  It does nothing here.
    123        doBuildBeforeAction(pipelineData);
    124
    125        // If an action has been defined, execute it here.  Actions
    126        // can re-define the template definition.
    127        if (data.hasAction())
    128        {
    129            actionLoader.exec(pipelineData, data.getAction());
    130        }
    131
    132        // if a redirect was setup in data, don't do anything else
    133        if (StringUtils.isNotEmpty(data.getRedirectURI()))
    134        {
    135            return;
    136        }
    137
    138        // Template pages can use this to set up default templates and
    139        // associated class modules.  It does nothing here.
    140        doBuildAfterAction(pipelineData);
    141
    142        String screenName = data.getScreen();
    143
    144        log.debug("Building " + screenName);
    145
    146        // Ask the Screen for its Layout and then execute the Layout.
    147        // The Screen can override the getLayout() method to re-define
    148        // the Layout depending on data passed in via the
    149        // data.parameters object.
    150        Screen aScreen = screenLoader.getAssembler(screenName);
    151        String layout = aScreen.getLayout(pipelineData);
    152
    153        // If the Layout has been set to be null, attempt to execute
    154        // the Screen that has been defined.
    155        if (layout != null)
    156        {
    157            layoutLoader.exec(pipelineData, layout);
    158        }
    159        else
    160        {
    161            screenLoader.exec(pipelineData, screenName);
    162        }
    163
    164        // Do any post build actions (overridable by subclasses -
    165        // does nothing here).
    166        doPostBuild(pipelineData);
    167    }
    168
    169    /**
    170     * Can be used by template Pages to stuff the Context into the
    171     * PipelineData so that it is available to the Action module and the
    172     * Screen module via getContext().  It does nothing here.
    173     *
    174     * @param pipelineData Turbine information.
    175     * @throws Exception a generic exception.
    176     */
    177    protected void doBuildBeforeAction(PipelineData pipelineData)
    178            throws Exception
    179    {
    180        // do nothing by default
    181    }
    182
    183    /**
    184     * Can be overridden by template Pages to set up data needed to
    185     * process a template.  It does nothing here.
    186     *
    187     * @param pipelineData Turbine information.
    188     * @throws Exception a generic exception.
    189     */
    190    protected void doBuildAfterAction(PipelineData pipelineData)
    191            throws Exception
    192    {
    193        // do nothing by default
    194    }
    195
    196    /**
    197     * Can be overridden to perform actions when the request is
    198     * fully processed. It does nothing here.
    199     *
    200     * @param pipelineData Turbine information.
    201     * @throws Exception a generic exception.
    202     */
    203    protected void doPostBuild(PipelineData pipelineData)
    204            throws Exception
    205    {
    206        // do nothing by default
    207    }
    208}