001package org.apache.turbine.modules.layouts; 002 003 004import javax.servlet.http.HttpServletResponse; 005 006import org.apache.logging.log4j.LogManager; 007 008/* 009 * Licensed to the Apache Software Foundation (ASF) under one 010 * or more contributor license agreements. See the NOTICE file 011 * distributed with this work for additional information 012 * regarding copyright ownership. The ASF licenses this file 013 * to you under the Apache License, Version 2.0 (the 014 * "License"); you may not use this file except in compliance 015 * with the License. You may obtain a copy of the License at 016 * 017 * http://www.apache.org/licenses/LICENSE-2.0 018 * 019 * Unless required by applicable law or agreed to in writing, 020 * software distributed under the License is distributed on an 021 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 022 * KIND, either express or implied. See the License for the 023 * specific language governing permissions and limitations 024 * under the License. 025 */ 026 027 028import org.apache.logging.log4j.Logger; 029import org.apache.turbine.Turbine; 030import org.apache.turbine.annotation.TurbineService; 031import org.apache.turbine.modules.Layout; 032import org.apache.turbine.pipeline.PipelineData; 033import org.apache.turbine.services.velocity.VelocityService; 034import org.apache.turbine.util.RunData; 035import org.apache.velocity.context.Context; 036 037/** 038 * This Layout module allows Velocity templates 039 * to be used as layouts. 040 * 041 * @author <a href="mailto:tv@apache.org">Thomas Vandahl</a> 042 */ 043public abstract class VelocityLayout implements Layout 044{ 045 /** Logging */ 046 protected final Logger log = LogManager.getLogger(this.getClass()); 047 048 /** The prefix for lookup up layout pages */ 049 protected static final String prefix = PREFIX + "/"; 050 051 /** Injected service instance */ 052 @TurbineService 053 protected VelocityService velocityService; 054 055 /** 056 * Method called by LayoutLoader. 057 * 058 * 059 * @param pipelineData PipelineData 060 * @throws Exception generic exception 061 */ 062 @Override 063 public void doBuild(PipelineData pipelineData) 064 throws Exception 065 { 066 RunData data = pipelineData.getRunData(); 067 // Get the context needed by Velocity. 068 Context context = velocityService.getContext(pipelineData); 069 070 // Provide objects to Velocity context 071 populateContext(pipelineData, context); 072 073 // Grab the layout template set in the VelocityPage. 074 // If null, then use the default layout template 075 // (done by the TemplateInfo object) 076 String templateName = data.getTemplateInfo().getLayoutTemplate(); 077 078 // Set the locale and content type 079 data.getResponse().setLocale(data.getLocale()); 080 data.getResponse().setContentType(data.getContentType()); 081 082 log.debug("Now trying to render layout {}", templateName); 083 084 // Finally, generate the layout template and send it to the browser 085 render(pipelineData, context, templateName); 086 } 087 088 /** 089 * Populate Velocity context 090 * 091 * @param pipelineData PipelineData 092 * @param context the Velocity context 093 * 094 * @throws Exception if evaluation fails 095 */ 096 protected abstract void populateContext(PipelineData pipelineData, Context context) 097 throws Exception; 098 099 /** 100 * Render layout 101 * 102 * @param pipelineData PipelineData 103 * @param context the Velocity context 104 * @param templateName relative path to Velocity template 105 * 106 * @throws Exception if rendering fails 107 */ 108 protected void render(PipelineData pipelineData, Context context, String templateName) 109 throws Exception 110 { 111 velocityService.handleRequest(context, 112 prefix + templateName, 113 pipelineData.get(Turbine.class, HttpServletResponse.class) 114 .getOutputStream()); 115 } 116}