1 /*
2 * Copyright (C) 2010, Sasa Zivkov <sasa.zivkov@sap.com>
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.nls;
45
46 import java.util.Locale;
47 import java.util.concurrent.ConcurrentHashMap;
48
49 import org.eclipse.jgit.errors.TranslationBundleLoadingException;
50 import org.eclipse.jgit.errors.TranslationStringMissingException;
51
52 /**
53 * The purpose of this class is to provide NLS (National Language Support)
54 * configurable per thread.
55 *
56 * <p>
57 * The {@link #setLocale(Locale)} method is used to configure locale for the
58 * calling thread. The locale setting is thread inheritable. This means that a
59 * child thread will have the same locale setting as its creator thread until it
60 * changes it explicitly.
61 *
62 * <p>
63 * Example of usage:
64 *
65 * <pre>
66 * NLS.setLocale(Locale.GERMAN);
67 * TransportText t = NLS.getBundleFor(TransportText.class);
68 * </pre>
69 */
70 public class NLS {
71 /**
72 * The root locale constant. It is defined here because the Locale.ROOT is
73 * not defined in Java 5
74 */
75 public static final Locale ROOT_LOCALE = new Locale("", "", ""); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
76
77 private static final InheritableThreadLocal<NLS> local = new InheritableThreadLocal<>();
78
79 /**
80 * Sets the locale for the calling thread.
81 * <p>
82 * The {@link #getBundleFor(Class)} method will honor this setting if if it
83 * is supported by the provided resource bundle property files. Otherwise,
84 * it will use a fall back locale as described in the
85 * {@link TranslationBundle}
86 *
87 * @param locale
88 * the preferred locale
89 */
90 public static void setLocale(Locale locale) {
91 local.set(new NLS(locale));
92 }
93
94 /**
95 * Sets the JVM default locale as the locale for the calling thread.
96 * <p>
97 * Semantically this is equivalent to
98 * <code>NLS.setLocale(Locale.getDefault())</code>.
99 */
100 public static void useJVMDefaultLocale() {
101 useJVMDefaultInternal();
102 }
103
104 // TODO(ms): change signature of public useJVMDefaultLocale() in 5.0 to get
105 // rid of this internal method
106 private static NLS useJVMDefaultInternal() {
107 NLS b = new NLS(Locale.getDefault());
108 local.set(b);
109 return b;
110 }
111
112 /**
113 * Returns an instance of the translation bundle of the required type. All
114 * public String fields of the bundle instance will get their values
115 * injected as described in the
116 * {@link org.eclipse.jgit.nls.TranslationBundle}.
117 *
118 * @param type
119 * required bundle type
120 * @return an instance of the required bundle type
121 * @exception TranslationBundleLoadingException
122 * see
123 * {@link org.eclipse.jgit.errors.TranslationBundleLoadingException}
124 * @exception TranslationStringMissingException
125 * see
126 * {@link org.eclipse.jgit.errors.TranslationStringMissingException}
127 */
128 public static <T extends TranslationBundle> T getBundleFor(Class<T> type) {
129 NLS b = local.get();
130 if (b == null) {
131 b = useJVMDefaultInternal();
132 }
133 return b.get(type);
134 }
135
136 final private Locale locale;
137 final private ConcurrentHashMap<Class, TranslationBundle> map = new ConcurrentHashMap<>();
138
139 private NLS(Locale locale) {
140 this.locale = locale;
141 }
142
143 @SuppressWarnings("unchecked")
144 private <T extends TranslationBundle> T get(Class<T> type) {
145 TranslationBundle bundle = map.get(type);
146 if (bundle == null) {
147 bundle = GlobalBundleCache.lookupBundle(locale, type);
148 // There is a small opportunity for a race, which we may
149 // lose. Accept defeat and return the winner's instance.
150 TranslationBundle old = map.putIfAbsent(type, bundle);
151 if (old != null)
152 bundle = old;
153 }
154 return (T) bundle;
155 }
156 }