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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.pipeline.PipelineData;
    26  import org.apache.turbine.util.RunData;
    27  import org.apache.velocity.context.Context;
    28
    29  /**
    30   * VelocityDirectScreen is a screen class which returns its output
    31   * directly to the output stream. It can be used if buffering an
    32   * output screen isn't possible or the result doesn't fit in the
    33   * memory.
    34   * <p>
    35   * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
    36   * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
    37   * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
    38   * @version $Id: VelocityDirectScreen.java 1773378 2016-12-09 13:19:59Z tv $
    39   */
    40  public class VelocityDirectScreen
    41      extends VelocityScreen
    42  {
    43      /** The prefix for lookup up screen pages */
    44      private String prefix = getPrefix() + "/";
    45
    46      /**
    47       * This builds the Velocity template.
    48       *
    49       * @param pipelineData Turbine information.
    50       * @return the content of the screen
    51       * @throws Exception a generic exception.
    52       */
    53      @Override
    54      public String buildTemplate(PipelineData pipelineData)
    55          throws Exception
    56      {
    57          RunData data = getRunData(pipelineData);
    58          Context context = velocity.getContext(pipelineData);
    59
    60          String screenTemplate = data.getTemplateInfo().getScreenTemplate();
    61          String templateName
    62              = templateService.getScreenTemplateName(screenTemplate);
    63
    64          // The Template Service could not find the Screen
    65          if (StringUtils.isEmpty(templateName))
    66          {
    67              log.error("Screen " + screenTemplate + " not found!");
    68              throw new Exception("Could not find screen for " + screenTemplate);
    69          }
    70
    71          try
    72          {
    73              velocity.handleRequest(context,
    74                                            prefix + templateName,
    75                                            data.getResponse().getOutputStream());
    76
    77          }
    78          catch (Exception e)
    79          {
    80              // If there is an error, build a $processingException and
    81              // attempt to call the error.vm template in the screens
    82              // directory.
    83              context.put (TurbineConstants.PROCESSING_EXCEPTION_PLACEHOLDER, e.toString());
    84              context.put (TurbineConstants.STACK_TRACE_PLACEHOLDER, ExceptionUtils.getStackTrace(e));
    85
    86              velocity.handleRequest(context, prefix + templateError,
    87                      data.getResponse().getOutputStream());
    88          }
    89
    90          return null;
    91      }
    92  }