1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.tomcat.util.res;
19
20 import java.text.MessageFormat;
21 import java.util.Hashtable;
22 import java.util.Locale;
23 import java.util.MissingResourceException;
24 import java.util.ResourceBundle;
25
26 /**
27 * An internationalization / localization helper class which reduces
28 * the bother of handling ResourceBundles and takes care of the
29 * common cases of message formating which otherwise require the
30 * creation of Object arrays and such.
31 *
32 * <p>The StringManager operates on a package basis. One StringManager
33 * per package can be created and accessed via the getManager method
34 * call.
35 *
36 * <p>The StringManager will look for a ResourceBundle named by
37 * the package name given plus the suffix of "LocalStrings". In
38 * practice, this means that the localized information will be contained
39 * in a LocalStrings.properties file located in the package
40 * directory of the classpath.
41 *
42 * <p>Please see the documentation for java.util.ResourceBundle for
43 * more information.
44 *
45 * @version $Revision: 769384 $ $Date: 2009-04-28 15:14:14 +0200 (Tue, 28 Apr 2009) $
46 *
47 * @author James Duncan Davidson [duncan@eng.sun.com]
48 * @author James Todd [gonzo@eng.sun.com]
49 * @author Mel Martinez [mmartinez@g1440.com]
50 * @see java.util.ResourceBundle
51 */
52
53 public class StringManager {
54
55 /**
56 * The ResourceBundle for this StringManager.
57 */
58
59 private ResourceBundle bundle;
60 private Locale locale;
61
62 /**
63 * Creates a new StringManager for a given package. This is a
64 * private method and all access to it is arbitrated by the
65 * static getManager method call so that only one StringManager
66 * per package will be created.
67 *
68 * @param packageName Name of package to create StringManager for.
69 */
70
71 private StringManager(String packageName) {
72 this( packageName, Locale.getDefault() );
73 }
74
75 private StringManager(String packageName, Locale loc) {
76 String bundleName = packageName + ".LocalStrings";
77 bundle = ResourceBundle.getBundle(bundleName, loc);
78 // Get the actual locale, which may be different from the requested one
79 locale = bundle.getLocale();
80 }
81
82 private StringManager(ResourceBundle bundle )
83 {
84 this.bundle=bundle;
85 locale = bundle.getLocale();
86 }
87
88 /**
89 Get a string from the underlying resource bundle or return
90 null if the String is not found.
91
92 @param key to desired resource String
93 @return resource String matching <i>key</i> from underlying
94 bundle or null if not found.
95 @throws IllegalArgumentException if <i>key</i> is null.
96 */
97
98 public String getString(String key) {
99 if(key == null){
100 String msg = "key may not have a null value";
101
102 throw new IllegalArgumentException(msg);
103 }
104
105 String str = null;
106
107 try{
108 str = bundle.getString(key);
109 }catch(MissingResourceException mre){
110 //bad: shouldn't mask an exception the following way:
111 // str = "[cannot find message associated with key '" + key + "' due to " + mre + "]";
112 // because it hides the fact that the String was missing
113 // from the calling code.
114 //good: could just throw the exception (or wrap it in another)
115 // but that would probably cause much havoc on existing
116 // code.
117 //better: consistent with container pattern to
118 // simply return null. Calling code can then do
119 // a null check.
120 str = null;
121 }
122
123 return str;
124 }
125
126 /**
127 * Get a string from the underlying resource bundle and format
128 * it with the given set of arguments.
129 *
130 * @param key
131 * @param args
132 */
133
134 public String getString(final String key, final Object... args) {
135 String value = getString(key);
136 if (value == null) {
137 value = key;
138 }
139
140 MessageFormat mf = new MessageFormat(value);
141 mf.setLocale(locale);
142 return mf.format(args, new StringBuffer(), null).toString();
143 }
144
145 // --------------------------------------------------------------
146 // STATIC SUPPORT METHODS
147 // --------------------------------------------------------------
148
149 private static Hashtable managers = new Hashtable();
150
151 /**
152 * Get the StringManager for a particular package. If a manager for
153 * a package already exists, it will be reused, else a new
154 * StringManager will be created and returned.
155 *
156 * @param packageName The package name
157 */
158 public synchronized static StringManager getManager(String packageName) {
159 StringManager mgr = (StringManager)managers.get(packageName);
160 if (mgr == null) {
161 mgr = new StringManager(packageName);
162 managers.put(packageName, mgr);
163 }
164 return mgr;
165 }
166
167 /**
168 * Get the StringManager for a particular package. If a manager for
169 * a package already exists, it will be reused, else a new
170 * StringManager will be created and returned.
171 *
172 * @param bundle The resource bundle
173 */
174 public synchronized static StringManager getManager(ResourceBundle bundle) {
175 return new StringManager( bundle );
176 }
177
178 /**
179 * Get the StringManager for a particular package and Locale. If a manager for
180 * a package already exists, it will be reused, else a new
181 * StringManager will be created for that Locale and returned.
182 *
183 * @param packageName The package name
184 * @param loc The locale
185 */
186
187 public synchronized static StringManager getManager(String packageName,Locale loc) {
188 StringManager mgr = (StringManager)managers.get(packageName+"_"+loc.toString());
189 if (mgr == null) {
190 mgr = new StringManager(packageName,loc);
191 managers.put(packageName+"_"+loc.toString(), mgr);
192 }
193 return mgr;
194 }
195
196 }