    001package org.apache.turbine.modules.screens;
    002
    003/*
    004 * Licensed to the Apache Software Foundation (ASF) under one
    005 * or more contributor license agreements.  See the NOTICE file
    006 * distributed with this work for additional information
    007 * regarding copyright ownership.  The ASF licenses this file
    008 * to you under the Apache License, Version 2.0 (the
    009 * "License"); you may not use this file except in compliance
    010 * with the License.  You may obtain a copy of the License at
    011 *
    012 *   http://www.apache.org/licenses/LICENSE-2.0
    013 *
    014 * Unless required by applicable law or agreed to in writing,
    015 * software distributed under the License is distributed on an
    016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    017 * KIND, either express or implied.  See the License for the
    018 * specific language governing permissions and limitations
    019 * under the License.
    020 */
    021
    022import org.apache.commons.lang.StringUtils;
    023import org.apache.commons.lang.exception.ExceptionUtils;
    024import org.apache.turbine.TurbineConstants;
    025import org.apache.turbine.pipeline.PipelineData;
    026import org.apache.turbine.util.RunData;
    027import org.apache.velocity.context.Context;
    028
    029/**
    030 * VelocityCachedScreen is Turbine 2.3.3 VelocityDirectScreen (same package)
    031 * with methods added for {@link PipelineData}.
    032 * It is is a screen class which buffers its output
    033 * before flushing the output stream. It is used in Jetspeed-1 portal.
    034 * <p>
    035 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
    036 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
    037 * @version $Id$
    038 */
    039public class VelocityCachedScreen
    040    extends VelocityScreen
    041{
    042    /** The prefix for lookup up screen pages */
    043    private String prefix = getPrefix() + "/";
    044
    045    /**
    046     * This builds the Velocity template.
    047     *
    048     * @param pipelineData Turbine information.
    049     * @return A ConcreteElement.
    050     * @exception Exception, a generic exception.
    051     */
    052    @Override
    053    public String buildTemplate(PipelineData pipelineData)
    054        throws Exception
    055    {
    056        RunData data = getRunData(pipelineData);
    057        Context context = velocity.getContext(pipelineData);
    058
    059        String screenTemplate = data.getTemplateInfo().getScreenTemplate();
    060        String templateName
    061            = templateService.getScreenTemplateName(screenTemplate);
    062
    063        // The Template Service could not find the Screen
    064        if (StringUtils.isEmpty(templateName))
    065        {
    066            log.error("Screen " + screenTemplate + " not found!");
    067            throw new Exception("Could not find screen for " + screenTemplate);
    068        }
    069
    070        try
    071        {
    072            velocity.handleRequest(context, prefix + templateName, data.getOut());
    073        }
    074        catch (Exception e)
    075        {
    076            // If there is an error, build a $processingException and
    077            // attempt to call the error.vm template in the screens
    078            // directory.
    079            context.put (TurbineConstants.PROCESSING_EXCEPTION_PLACEHOLDER, e.toString());
    080            context.put (TurbineConstants.STACK_TRACE_PLACEHOLDER, ExceptionUtils.getStackTrace(e));
    081
    082            templateName = conf.getString(TurbineConstants.TEMPLATE_ERROR_KEY,
    083                           TurbineConstants.TEMPLATE_ERROR_VM);
    084
    085            velocity.handleRequest(context, prefix + templateName, data.getOut());
    086        }
    087
    088        return null;
    089    }
    090}
    091
    092