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.configuration.Configuration; 023import org.apache.commons.lang.StringUtils; 024import org.apache.commons.lang.exception.ExceptionUtils; 025import org.apache.turbine.TurbineConstants; 026import org.apache.turbine.annotation.TurbineConfiguration; 027import org.apache.turbine.annotation.TurbineService; 028import org.apache.turbine.pipeline.PipelineData; 029import org.apache.turbine.services.template.TemplateService; 030import org.apache.turbine.services.velocity.VelocityService; 031import org.apache.turbine.util.RunData; 032import org.apache.velocity.context.Context; 033 034/** 035 * Base Velocity Screen. The buildTemplate() assumes the template 036 * parameter has been set in the PipelineData object. This provides the 037 * ability to execute several templates from one Screen. 038 * 039 * <p> 040 * 041 * If you need more specific behavior in your application, extend this 042 * class and override the doBuildTemplate() method. 043 * 044 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a> 045 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a> 046 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a> 047 * @version $Id: VelocityScreen.java 1709648 2015-10-20 17:08:10Z tv $ 048 */ 049public class VelocityScreen 050 extends TemplateScreen 051{ 052 /** The prefix for lookup up screen pages */ 053 private final String prefix = getPrefix() + "/"; 054 055 /** Injected service instance */ 056 @TurbineService 057 protected VelocityService velocity; 058 059 /** Injected service instance */ 060 @TurbineService 061 protected TemplateService templateService; 062 063 /** Injected configuration instance */ 064 @TurbineConfiguration 065 protected Configuration conf; 066 067 /** 068 * Velocity Screens extending this class should override this 069 * method to perform any particular business logic and add 070 * information to the context. 071 * 072 * @param pipelineData Turbine information. 073 * @param context Context for web pages. 074 * @exception Exception, a generic exception. 075 */ 076 protected void doBuildTemplate(PipelineData pipelineData, 077 Context context) 078 throws Exception 079 { 080 // empty 081 } 082 083 /** 084 * Needs to be implemented to make TemplateScreen like us. The 085 * actual method that you should override is the one with the 086 * context in the parameter list. 087 * 088 * @param pipelineData Turbine information. 089 * @exception Exception, a generic exception. 090 */ 091 @Override 092 protected void doBuildTemplate(PipelineData pipelineData) 093 throws Exception 094 { 095 doBuildTemplate(pipelineData, velocity.getContext(pipelineData)); 096 } 097 098 /** 099 * 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}