001 package 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 */ 022 023 024 import org.apache.ecs.ConcreteElement; 025 import org.apache.turbine.Turbine; 026 import org.apache.turbine.pipeline.PipelineData; 027 import org.apache.turbine.util.RunData; 028 029 /** 030 * The purpose of this class is to allow one to load and execute 031 * Screen modules. 032 * 033 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a> 034 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a> 035 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a> 036 * @version $Id: ScreenLoader.java 1078552 2011-03-06 19:58:46Z tv $ 037 */ 038 public class ScreenLoader 039 extends GenericLoader<Screen> 040 implements Loader<Screen> 041 { 042 /** The single instance of this class. */ 043 private static ScreenLoader instance = new ScreenLoader(); 044 045 /** 046 * These ctor's are private to force clients to use getInstance() 047 * to access this class. 048 */ 049 private ScreenLoader() 050 { 051 super(); 052 } 053 054 /** 055 * Attempts to load and execute the external Screen. This is used 056 * when you want to execute a Screen which returns its output via 057 * a MultiPartElement instead of out the data.getPage() value. 058 * This allows you to easily chain the execution of Screen modules 059 * together. 060 * 061 * @deprecated Use PipelineData version instead. 062 * @param data Turbine information. 063 * @param name Name of object that will execute the screen. 064 * @exception Exception a generic exception. 065 */ 066 @Deprecated 067 public ConcreteElement eval(RunData data, String name) 068 throws Exception 069 { 070 // Execute screen 071 return getAssembler(name).build(data); 072 } 073 074 /** 075 * Attempts to load and execute the external Screen. This is used 076 * when you want to execute a Screen which returns its output via 077 * a MultiPartElement instead of out the data.getPage() value. 078 * This allows you to easily chain the execution of Screen modules 079 * together. 080 * 081 * @param data Turbine information. 082 * @param name Name of object that will execute the screen. 083 * @exception Exception a generic exception. 084 */ 085 public ConcreteElement eval(PipelineData pipelineData, String name) 086 throws Exception 087 { 088 // Execute screen 089 return getAssembler(name).build(pipelineData); 090 } 091 092 /** 093 * Attempts to load and execute the Screen. This is used when you 094 * want to execute a Screen which returns its output via the 095 * data.getPage() object. 096 * @deprecated Use PipelineData version instead. 097 * @param data Turbine information. 098 * @param name Name of object that will execute the screen. 099 * @exception Exception a generic exception. 100 */ 101 @Deprecated 102 @Override 103 public void exec(RunData data, String name) 104 throws Exception 105 { 106 this.eval(data, name); 107 } 108 109 /** 110 * Attempts to load and execute the Screen. This is used when you 111 * want to execute a Screen which returns its output via the 112 * data.getPage() object. 113 * 114 * @param data Turbine information. 115 * @param name Name of object that will execute the screen. 116 * @exception Exception a generic exception. 117 */ 118 @Override 119 public void exec(PipelineData pipelineData, String name) 120 throws Exception 121 { 122 this.eval(pipelineData, name); 123 } 124 125 /** 126 * Pulls out an instance of the object by name. Name is just the 127 * single name of the object. This is equal to getInstance but 128 * returns an Assembler object and is needed to fulfil the Loader 129 * interface. 130 * 131 * @param name Name of object instance. 132 * @return A Screen with the specified name, or null. 133 * @exception Exception a generic exception. 134 */ 135 public Screen getAssembler(String name) 136 throws Exception 137 { 138 return getAssembler(Screen.NAME, name); 139 } 140 141 /** 142 * @see org.apache.turbine.modules.Loader#getCacheSize() 143 */ 144 public int getCacheSize() 145 { 146 return ScreenLoader.getConfiguredCacheSize(); 147 } 148 149 /** 150 * The method through which this class is accessed. 151 * 152 * @return The single instance of this class. 153 */ 154 public static ScreenLoader getInstance() 155 { 156 return instance; 157 } 158 159 /** 160 * Helper method to get the configured cache size for this module 161 * 162 * @return the configure cache size 163 */ 164 private static int getConfiguredCacheSize() 165 { 166 return Turbine.getConfiguration().getInt(Screen.CACHE_SIZE_KEY, 167 Screen.CACHE_SIZE_DEFAULT); 168 } 169 }