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    1   package org.apache.turbine.modules.screens;
    2
    3   /*
    4    * Licensed to the Apache Software Foundation (ASF) under one
    5    * or more contributor license agreements.  See the NOTICE file
    6    * distributed with this work for additional information
    7    * regarding copyright ownership.  The ASF licenses this file
    8    * to you under the Apache License, Version 2.0 (the
    9    * "License"); you may not use this file except in compliance
    10   * with the License.  You may obtain a copy of the License at
    11   *
    12   *   http://www.apache.org/licenses/LICENSE-2.0
    13   *
    14   * Unless required by applicable law or agreed to in writing,
    15   * software distributed under the License is distributed on an
    16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    17   * KIND, either express or implied.  See the License for the
    18   * specific language governing permissions and limitations
    19   * under the License.
    20   */
    21
    22  import org.apache.commons.lang.StringUtils;
    23  import org.apache.commons.lang.exception.ExceptionUtils;
    24  import org.apache.turbine.TurbineConstants;
    25  import org.apache.turbine.annotation.TurbineConfiguration;
    26  import org.apache.turbine.annotation.TurbineService;
    27  import org.apache.turbine.pipeline.PipelineData;
    28  import org.apache.turbine.services.template.TemplateService;
    29  import org.apache.turbine.services.velocity.VelocityService;
    30  import org.apache.turbine.util.RunData;
    31  import org.apache.velocity.context.Context;
    32
    33  /**
    34   * Base Velocity Screen.  The buildTemplate() assumes the template
    35   * parameter has been set in the PipelineData object.  This provides the
    36   * ability to execute several templates from one Screen.
    37   *
    38   * <p>
    39   *
    40   * If you need more specific behavior in your application, extend this
    41   * class and override the doBuildTemplate() method.
    42   *
    43   * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
    44   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
    45   * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
    46   * @version $Id: VelocityScreen.java 1773378 2016-12-09 13:19:59Z tv $
    47   */
    48  public class VelocityScreen
    49      extends TemplateScreen
    50  {
    51      /** The prefix for lookup up screen pages */
    52      private final String prefix = getPrefix() + "/";
    53
    54      /** Injected service instance */
    55      @TurbineService
    56      protected VelocityService velocity;
    57
    58      /** Injected service instance */
    59      @TurbineService
    60      protected TemplateService templateService;
    61
    62      @TurbineConfiguration( TurbineConstants.TEMPLATE_ERROR_KEY )
    63      protected String templateError = TurbineConstants.TEMPLATE_ERROR_VM;
    64
    65      /**
    66       * Velocity Screens extending this class should override this
    67       * method to perform any particular business logic and add
    68       * information to the context.
    69       *
    70       * @param pipelineData Turbine information.
    71       * @param context Context for web pages.
    72       * @throws Exception a generic exception.
    73       */
    74      protected void doBuildTemplate(PipelineData pipelineData,
    75                                     Context context)
    76              throws Exception
    77      {
    78          // empty
    79      }
    80
    81      /**
    82       * Needs to be implemented to make TemplateScreen like us.  The
    83       * actual method that you should override is the one with the
    84       * context in the parameter list.
    85       *
    86       * @param pipelineData Turbine information.
    87       * @throws Exception a generic exception.
    88       */
    89      @Override
    90      protected void doBuildTemplate(PipelineData pipelineData)
    91              throws Exception
    92      {
    93          doBuildTemplate(pipelineData, velocity.getContext(pipelineData));
    94      }
    95
    96      /**
    97       * This builds the Velocity template.
    98       *
    99       * @param pipelineData Turbine information.
    100      * @return the content of the screen
    101      * @throws Exception a generic exception.
    102      */
    103     @Override
    104     public String buildTemplate(PipelineData pipelineData)
    105         throws Exception
    106     {
    107         RunData data = getRunData(pipelineData);
    108         String screenData = null;
    109
    110         Context context = velocity.getContext(pipelineData);
    111
    112         String screenTemplate = data.getTemplateInfo().getScreenTemplate();
    113         String templateName
    114             = templateService.getScreenTemplateName(screenTemplate);
    115
    116         // The Template Service could not find the Screen
    117         if (StringUtils.isEmpty(templateName))
    118         {
    119             log.error("Screen " + screenTemplate + " not found!");
    120             throw new Exception("Could not find screen for " + screenTemplate);
    121         }
    122
    123         try
    124         {
    125             // if a layout has been defined return the results, otherwise
    126             // send the results directly to the output stream.
    127             if (getLayout(pipelineData) == null)
    128             {
    129                 velocity.handleRequest(context,
    130                         prefix + templateName,
    131                         data.getResponse().getOutputStream());
    132             }
    133             else
    134             {
    135                 screenData =
    136                     velocity.handleRequest(context, prefix + templateName);
    137             }
    138         }
    139         catch (Exception e)
    140         {
    141             // If there is an error, build a $processingException and
    142             // attempt to call the error.vm template in the screens
    143             // directory.
    144             context.put (TurbineConstants.PROCESSING_EXCEPTION_PLACEHOLDER, e.toString());
    145             context.put (TurbineConstants.STACK_TRACE_PLACEHOLDER, ExceptionUtils.getStackTrace(e));
    146
    147             screenData = velocity.handleRequest(context, prefix + templateError);
    148         }
    149
    150         return screenData;
    151     }
    152 }