View Javadoc

    1   package org.apache.turbine.modules.pages;
    2
    3
    4   /*
    5    * Licensed to the Apache Software Foundation (ASF) under one
    6    * or more contributor license agreements.  See the NOTICE file
    7    * distributed with this work for additional information
    8    * regarding copyright ownership.  The ASF licenses this file
    9    * to you under the Apache License, Version 2.0 (the
    10   * "License"); you may not use this file except in compliance
    11   * with the License.  You may obtain a copy of the License at
    12   *
    13   *   http://www.apache.org/licenses/LICENSE-2.0
    14   *
    15   * Unless required by applicable law or agreed to in writing,
    16   * software distributed under the License is distributed on an
    17   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    18   * KIND, either express or implied.  See the License for the
    19   * specific language governing permissions and limitations
    20   * under the License.
    21   */
    22
    23
    24  import org.apache.commons.lang.StringUtils;
    25  import org.apache.commons.logging.Log;
    26  import org.apache.commons.logging.LogFactory;
    27  import org.apache.turbine.annotation.TurbineLoader;
    28  import org.apache.turbine.modules.Action;
    29  import org.apache.turbine.modules.ActionLoader;
    30  import org.apache.turbine.modules.Layout;
    31  import org.apache.turbine.modules.LayoutLoader;
    32  import org.apache.turbine.modules.Page;
    33  import org.apache.turbine.modules.Screen;
    34  import org.apache.turbine.modules.ScreenLoader;
    35  import org.apache.turbine.pipeline.PipelineData;
    36  import org.apache.turbine.util.RunData;
    37
    38  /**
    39   * When building sites using templates, Screens need only be defined
    40   * for templates which require dynamic (database or object) data.
    41   *
    42   * <p>
    43   *
    44   * This page can be used on sites where the number of Screens can be
    45   * much less than the number of templates.  The templates can be
    46   * grouped in directories with common layouts.  Screen modules are
    47   * then expected to be placed in packages corresponding with the
    48   * templates' directories and follow a specific naming scheme.
    49   *
    50   * <p>
    51   *
    52   * The template parameter is parsed and and a Screen whose package
    53   * matches the templates path and shares the same name minus any
    54   * extension and beginning with a capital letter is searched for.  If
    55   * not found, a Screen in a package matching the template's path with
    56   * name Default is searched for.  If still not found, a Screen with
    57   * name Default is looked for in packages corresponding to parent
    58   * directories in the template's path until a match is found.
    59   *
    60   * <p>
    61   *
    62   * For example if data.getParameters().getString("template") returns
    63   * /about_us/directions/driving.wm, the search follows
    64   * about_us.directions.Driving, about_us.directions.Default,
    65   * about_us.Default, Default, VelocitySiteScreen.
    66   *
    67   * <p>
    68   *
    69   * Only one Layout module is used, since it is expected that any
    70   * dynamic content will be placed in navigations and screens.  The
    71   * layout template to be used is found in a similar way to the Screen.
    72   * For example the following paths will be searched in the layouts
    73   * subdirectory: /about_us/directions/driving.wm,
    74   * /about_us/directions/default.wm, /about_us/default.wm, /default.wm.
    75   *
    76   * <p>
    77   *
    78   * This approach allows a site with largely static content to be
    79   * updated and added to regularly by those with little Java
    80   * experience.
    81   *
    82   * <p>
    83   *
    84   * The code is an almost a complete clone of the FreeMarkerSitePage
    85   * written by John McNally.  I've only modified it for Template use.
    86   *
    87   * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
    88   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
    89   * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
    90   * @version $Id: DefaultPage.java 1709648 2015-10-20 17:08:10Z tv $
    91   */
    92  public class DefaultPage
    93      extends Page
    94  {
    95      /** Logging */
    96      protected Log log = LogFactory.getLog(this.getClass());
    97
    98      /** Injected loader instance */
    99      @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      * @exception 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      * @exception 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      * @exception 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      * @exception Exception, a generic exception.
    202      */
    203     protected void doPostBuild(PipelineData pipelineData)
    204             throws Exception
    205     {
    206         // do nothing by default
    207     }
    208 }