1 /* 2 * $Id$ 3 * 4 * Licensed to the Apache Software Foundation (ASF) under one 5 * or more contributor license agreements. See the NOTICE file 6 * distributed with this work for additional information 7 * regarding copyright ownership. The ASF licenses this file 8 * to you under the Apache License, Version 2.0 (the 9 * "License"); you may not use this file except in compliance 10 * with the License. You may obtain a copy of the License at 11 * 12 * http://www.apache.org/licenses/LICENSE-2.0 13 * 14 * Unless required by applicable law or agreed to in writing, 15 * software distributed under the License is distributed on an 16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 17 * KIND, either express or implied. See the License for the 18 * specific language governing permissions and limitations 19 * under the License. 20 */ 21 package org.apache.struts.util; 22 23 import java.io.Serializable; 24 25 import org.apache.struts.config.MessageResourcesConfig; 26 import org.slf4j.Logger; 27 import org.slf4j.LoggerFactory; 28 29 /** 30 * Factory for <code>MessageResources</code> instances. The general usage 31 * pattern for this class is: 32 * 33 * <ul> 34 * 35 * <li>Call <code>MessageResourcesFactory().createFactory()</code> to retrieve 36 * a <code>MessageResourcesFactory</code> instance.</li> <li>Set properties as 37 * required to configure this factory instance to create 38 * <code>MessageResources</code> instances with desired characteristics.</li> 39 * 40 * <li>Call the <code>createResources()</code> method of the factory to 41 * retrieve a newly instantiated <code>MessageResources</code> instance.</li> 42 * 43 * </ul> 44 * 45 * @version $Rev$ $Date: 2005-08-29 23:57:50 -0400 (Mon, 29 Aug 2005) 46 * $ 47 */ 48 public abstract class MessageResourcesFactory implements Serializable { 49 private static final long serialVersionUID = 4038049321455270344L; 50 51 // ------------------------------------------------------ Static Properties 52 53 /** 54 * The Java class to be used for <code>MessageResourcesFactory</code> 55 * instances. 56 */ 57 protected static transient Class<? extends MessageResourcesFactory> clazz = null; 58 59 /** 60 * The {@code Log} instance for this class. 61 */ 62 private final static Logger LOG = 63 LoggerFactory.getLogger(MessageResourcesFactory.class); 64 65 /** 66 * The fully qualified class name to be used for <code>MessageResourcesFactory</code> 67 * instances. 68 */ 69 protected static String factoryClass = 70 "org.apache.struts.util.PropertyMessageResourcesFactory"; 71 72 // ---------------------------------------------------- Instance Properties 73 74 /** 75 * Configuration information for Message Resources. 76 */ 77 protected MessageResourcesConfig config; 78 79 /** 80 * The "return null" property value to which newly created 81 * MessageResourcess should be initialized. 82 */ 83 protected boolean returnNull = true; 84 85 /** 86 * Set the configuration information for Message Resources. 87 * 88 * @since Struts 1.2.8 89 */ 90 public MessageResourcesConfig getConfig() { 91 return config; 92 } 93 94 /** 95 * Return the configuration information for Message Resources. 96 * 97 * @since Struts 1.2.8 98 */ 99 public void setConfig(MessageResourcesConfig config) { 100 this.config = config; 101 } 102 103 /** 104 * Get default value of the "returnNull" property used to initialize newly 105 * created MessageResourcess. 106 * 107 * @return default value of the "returnNull" property newly created 108 * MessageResourcess are initialized to. 109 */ 110 public boolean getReturnNull() { 111 return (this.returnNull); 112 } 113 114 /** 115 * Set the default value of the "returnNull" property newly created 116 * MessageResourcess are initialized to. 117 * 118 * @param returnNull default value of the "returnNull" MessageResourcess 119 * are initialized to. 120 */ 121 public void setReturnNull(boolean returnNull) { 122 this.returnNull = returnNull; 123 } 124 125 // --------------------------------------------------------- Public Methods 126 127 /** 128 * Create and return a newly instansiated <code>MessageResources</code>. 129 * This method must be implemented by concrete subclasses. 130 * 131 * @param config Configuration parameter(s) for the requested bundle 132 */ 133 public abstract MessageResources createResources(String config); 134 135 /** 136 * The fully qualified class name that is used for <code>MessageResourcesFactory</code> 137 * instances. 138 * 139 * @return class name that is used for <code>MessageResourcesFactory</code> 140 * instances 141 */ 142 public static String getFactoryClass() { 143 return (MessageResourcesFactory.factoryClass); 144 } 145 146 /** 147 * Set the fully qualified class name that is used for 148 * <code>MessageResourcesFactory</code> instances. 149 * 150 * @param factoryClass name that is used for <code>MessageResourcesFactory</code> 151 * instances 152 */ 153 public static void setFactoryClass(String factoryClass) { 154 MessageResourcesFactory.factoryClass = factoryClass; 155 MessageResourcesFactory.clazz = null; 156 } 157 158 // --------------------------------------------------------- Static Methods 159 160 /** 161 * Create and return a <code>MessageResourcesFactory</code> instance of 162 * the appropriate class, which can be used to create customized 163 * <code>MessageResources</code> instances. If no such factory can be 164 * created, return <code>null</code> instead. 165 */ 166 public static MessageResourcesFactory createFactory() { 167 // Construct a new instance of the specified factory class 168 try { 169 if (clazz == null) { 170 clazz = RequestUtils.applicationClass(factoryClass) 171 .asSubclass(MessageResourcesFactory.class); 172 } 173 174 MessageResourcesFactory factory = clazz.getDeclaredConstructor().newInstance(); 175 176 return (factory); 177 } catch (Throwable t) { 178 LOG.error("MessageResourcesFactory.createFactory", t); 179 180 return (null); 181 } 182 } 183 }