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 }