001package org.apache.turbine.modules; 002 003 004/* 005 * Licensed to the Apache Software Foundation (ASF) under one 006 * or more contributor license agreements. See the NOTICE file 007 * distributed with this work for additional information 008 * regarding copyright ownership. The ASF licenses this file 009 * to you under the Apache License, Version 2.0 (the 010 * "License"); you may not use this file except in compliance 011 * with the License. You may obtain a copy of the License at 012 * 013 * http://www.apache.org/licenses/LICENSE-2.0 014 * 015 * Unless required by applicable law or agreed to in writing, 016 * software distributed under the License is distributed on an 017 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 018 * KIND, either express or implied. See the License for the 019 * specific language governing permissions and limitations 020 * under the License. 021 */ 022 023 024import org.apache.turbine.pipeline.PipelineData; 025import org.apache.turbine.util.RunData; 026 027/** 028 * This is the interface which defines the Screen modules. 029 * 030 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a> 031 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a> 032 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a> 033 * @version $Id$ 034 */ 035@FunctionalInterface 036public interface Screen extends Assembler 037{ 038 /** Prefix for screen related classes and templates */ 039 String PREFIX = "screens"; 040 041 /** Property for the size of the screen cache if caching is on */ 042 String CACHE_SIZE_KEY = "screen.cache.size"; 043 044 /** The default size for the screen cache */ 045 int CACHE_SIZE_DEFAULT = 50; 046 047 /** Represents Screen Objects */ 048 String NAME = "screen"; 049 050 /** 051 * A subclass must implement this method to build itself. 052 * Subclasses override this method to store the screen in RunData 053 * or to write the screen to the output stream referenced in 054 * RunData. 055 * @param pipelineData Turbine information. 056 * @return the content of the screen 057 * @throws Exception a generic exception. 058 */ 059 String doBuild(PipelineData pipelineData) throws Exception; 060 061 /** 062 * Subclasses can override this method to add additional 063 * functionality. 064 * 065 * @param pipelineData Turbine information. 066 * @return the content of the screen 067 * @throws Exception a generic exception. 068 */ 069 default String build(PipelineData pipelineData) 070 throws Exception 071 { 072 return doBuild(pipelineData); 073 } 074 075 /** 076 * If the Layout has not been defined by the Screen then set the 077 * layout to be "DefaultLayout". The Screen object can also 078 * override this method to provide intelligent determination of 079 * the Layout to execute. You can also define that logic here as 080 * well if you want it to apply on a global scale. For example, 081 * if you wanted to allow someone to define Layout "preferences" 082 * where they could dynamically change the Layout for the entire 083 * site. The information for the request is passed in with the 084 * PipelineData object. 085 * 086 * @param pipelineData Turbine information. 087 * @return A String with the Layout. 088 */ 089 default String getLayout(PipelineData pipelineData) 090 { 091 RunData data = pipelineData.getRunData(); 092 return data.getLayout(); 093 } 094 095 /** 096 * Set the layout for a Screen. 097 * 098 * @param pipelineData Turbine information. 099 * @param layout The layout name. 100 */ 101 default void setLayout(PipelineData pipelineData, String layout) 102 { 103 RunData data = pipelineData.getRunData(); 104 data.setLayout(layout); 105 } 106}