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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   * VelocityCachedScreen is Turbine 2.3.3 VelocityDirectScreen (same package)
    31   * with methods added for {@link PipelineData}.
    32   * It is is a screen class which buffers its output
    33   * before flushing the output stream. It is used in Jetspeed-1 portal.
    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   * @version $Id$
    38   */
    39  public class VelocityCachedScreen
    40      extends VelocityScreen
    41  {
    42      /** The prefix for lookup up screen pages */
    43      private String prefix = getPrefix() + "/";
    44
    45      /**
    46       * This builds the Velocity template.
    47       *
    48       * @param pipelineData Turbine information.
    49       * @return A ConcreteElement.
    50       * @throws Exception a generic exception.
    51       */
    52      @Override
    53      public String buildTemplate(PipelineData pipelineData)
    54          throws Exception
    55      {
    56          RunData data = getRunData(pipelineData);
    57          Context context = velocity.getContext(pipelineData);
    58
    59          String screenTemplate = data.getTemplateInfo().getScreenTemplate();
    60          String templateName
    61              = templateService.getScreenTemplateName(screenTemplate);
    62
    63          // The Template Service could not find the Screen
    64          if (StringUtils.isEmpty(templateName))
    65          {
    66              log.error("Screen " + screenTemplate + " not found!");
    67              throw new Exception("Could not find screen for " + screenTemplate);
    68          }
    69
    70          try
    71          {
    72              velocity.handleRequest(context, prefix + templateName, data.getOut());
    73          }
    74          catch (Exception e)
    75          {
    76              // If there is an error, build a $processingException and
    77              // attempt to call the error.vm template in the screens
    78              // directory.
    79              context.put (TurbineConstants.PROCESSING_EXCEPTION_PLACEHOLDER, e.toString());
    80              context.put (TurbineConstants.STACK_TRACE_PLACEHOLDER, ExceptionUtils.getStackTrace(e));
    81
    82              velocity.handleRequest(context, prefix + templateError, data.getOut());
    83          }
    84
    85          return null;
    86      }
    87  }
    88
    89