1 package org.apache.turbine.modules; 2 3 4 /* 5 * Licensed to the Apache Software Foundation (ASF) under one 6 * or more contributor license agreements. See the NOTICE file 7 * distributed with this work for additional information 8 * regarding copyright ownership. The ASF licenses this file 9 * to you under the Apache License, Version 2.0 (the 10 * "License"); you may not use this file except in compliance 11 * with the License. You may obtain a copy of the License at 12 * 13 * http://www.apache.org/licenses/LICENSE-2.0 14 * 15 * Unless required by applicable law or agreed to in writing, 16 * software distributed under the License is distributed on an 17 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 18 * KIND, either express or implied. See the License for the 19 * specific language governing permissions and limitations 20 * under the License. 21 */ 22 23 24 import org.apache.ecs.ConcreteElement; 25 import org.apache.turbine.Turbine; 26 import org.apache.turbine.pipeline.PipelineData; 27 import org.apache.turbine.util.RunData; 28 29 /** 30 * The purpose of this class is to allow one to load and execute 31 * Screen modules. 32 * 33 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a> 34 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a> 35 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a> 36 * @version $Id: ScreenLoader.java 1078552 2011-03-06 19:58:46Z tv $ 37 */ 38 public class ScreenLoader 39 extends GenericLoader<Screen> 40 implements Loader<Screen> 41 { 42 /** The single instance of this class. */ 43 private static ScreenLoader instance = new ScreenLoader(); 44 45 /** 46 * These ctor's are private to force clients to use getInstance() 47 * to access this class. 48 */ 49 private ScreenLoader() 50 { 51 super(); 52 } 53 54 /** 55 * Attempts to load and execute the external Screen. This is used 56 * when you want to execute a Screen which returns its output via 57 * a MultiPartElement instead of out the data.getPage() value. 58 * This allows you to easily chain the execution of Screen modules 59 * together. 60 * 61 * @deprecated Use PipelineData version instead. 62 * @param data Turbine information. 63 * @param name Name of object that will execute the screen. 64 * @exception Exception a generic exception. 65 */ 66 @Deprecated 67 public ConcreteElement eval(RunData data, String name) 68 throws Exception 69 { 70 // Execute screen 71 return getAssembler(name).build(data); 72 } 73 74 /** 75 * Attempts to load and execute the external Screen. This is used 76 * when you want to execute a Screen which returns its output via 77 * a MultiPartElement instead of out the data.getPage() value. 78 * This allows you to easily chain the execution of Screen modules 79 * together. 80 * 81 * @param data Turbine information. 82 * @param name Name of object that will execute the screen. 83 * @exception Exception a generic exception. 84 */ 85 public ConcreteElement eval(PipelineData pipelineData, String name) 86 throws Exception 87 { 88 // Execute screen 89 return getAssembler(name).build(pipelineData); 90 } 91 92 /** 93 * Attempts to load and execute the Screen. This is used when you 94 * want to execute a Screen which returns its output via the 95 * data.getPage() object. 96 * @deprecated Use PipelineData version instead. 97 * @param data Turbine information. 98 * @param name Name of object that will execute the screen. 99 * @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 }