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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.configuration.Configuration;
    23  import org.apache.commons.lang.StringUtils;
    24  import org.apache.commons.lang.exception.ExceptionUtils;
    25  import org.apache.turbine.TurbineConstants;
    26  import org.apache.turbine.annotation.TurbineConfiguration;
    27  import org.apache.turbine.annotation.TurbineService;
    28  import org.apache.turbine.pipeline.PipelineData;
    29  import org.apache.turbine.services.template.TemplateService;
    30  import org.apache.turbine.services.velocity.VelocityService;
    31  import org.apache.turbine.util.RunData;
    32  import org.apache.velocity.context.Context;
    33
    34  /**
    35   * Base Velocity Screen.  The buildTemplate() assumes the template
    36   * parameter has been set in the PipelineData object.  This provides the
    37   * ability to execute several templates from one Screen.
    38   *
    39   * <p>
    40   *
    41   * If you need more specific behavior in your application, extend this
    42   * class and override the doBuildTemplate() method.
    43   *
    44   * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
    45   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
    46   * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
    47   * @version $Id: VelocityScreen.java 1709648 2015-10-20 17:08:10Z tv $
    48   */
    49  public class VelocityScreen
    50      extends TemplateScreen
    51  {
    52      /** The prefix for lookup up screen pages */
    53      private final String prefix = getPrefix() + "/";
    54
    55      /** Injected service instance */
    56      @TurbineService
    57      protected VelocityService velocity;
    58
    59      /** Injected service instance */
    60      @TurbineService
    61      protected TemplateService templateService;
    62
    63      /** Injected configuration instance */
    64      @TurbineConfiguration
    65      protected Configuration conf;
    66
    67      /**
    68       * Velocity Screens extending this class should override this
    69       * method to perform any particular business logic and add
    70       * information to the context.
    71       *
    72       * @param pipelineData Turbine information.
    73       * @param context Context for web pages.
    74       * @exception Exception, a generic exception.
    75       */
    76      protected void doBuildTemplate(PipelineData pipelineData,
    77                                     Context context)
    78              throws Exception
    79      {
    80          // empty
    81      }
    82
    83      /**
    84       * Needs to be implemented to make TemplateScreen like us.  The
    85       * actual method that you should override is the one with the
    86       * context in the parameter list.
    87       *
    88       * @param pipelineData Turbine information.
    89       * @exception Exception, a generic exception.
    90       */
    91      @Override
    92      protected void doBuildTemplate(PipelineData pipelineData)
    93              throws Exception
    94      {
    95          doBuildTemplate(pipelineData, velocity.getContext(pipelineData));
    96      }
    97
    98      /**
    99       * This builds the Velocity template.
    100      *
    101      * @param pipelineData Turbine information.
    102      * @return the content of the screen
    103      * @exception Exception, a generic exception.
    104      */
    105     @Override
    106     public String buildTemplate(PipelineData pipelineData)
    107         throws Exception
    108     {
    109         RunData data = getRunData(pipelineData);
    110         String screenData = null;
    111
    112         Context context = velocity.getContext(pipelineData);
    113
    114         String screenTemplate = data.getTemplateInfo().getScreenTemplate();
    115         String templateName
    116             = templateService.getScreenTemplateName(screenTemplate);
    117
    118         // The Template Service could not find the Screen
    119         if (StringUtils.isEmpty(templateName))
    120         {
    121             log.error("Screen " + screenTemplate + " not found!");
    122             throw new Exception("Could not find screen for " + screenTemplate);
    123         }
    124
    125         try
    126         {
    127             // if a layout has been defined return the results, otherwise
    128             // send the results directly to the output stream.
    129             if (getLayout(pipelineData) == null)
    130             {
    131                 velocity.handleRequest(context,
    132                         prefix + templateName,
    133                         data.getResponse().getOutputStream());
    134             }
    135             else
    136             {
    137                 screenData =
    138                     velocity.handleRequest(context, prefix + templateName);
    139             }
    140         }
    141         catch (Exception e)
    142         {
    143             // If there is an error, build a $processingException and
    144             // attempt to call the error.vm template in the screens
    145             // directory.
    146             context.put (TurbineConstants.PROCESSING_EXCEPTION_PLACEHOLDER, e.toString());
    147             context.put (TurbineConstants.STACK_TRACE_PLACEHOLDER, ExceptionUtils.getStackTrace(e));
    148
    149             templateName = conf.getString(TurbineConstants.TEMPLATE_ERROR_KEY,
    150                            TurbineConstants.TEMPLATE_ERROR_VM);
    151
    152             screenData = velocity.handleRequest(context, prefix + templateName);
    153         }
    154
    155         return screenData;
    156     }
    157 }