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 /** The root locale constant. It is defined here because the Locale.ROOT is not defined in Java 5 */ 72 public static final Locale ROOT_LOCALE = new Locale("", "", ""); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ 73 74 private static final InheritableThreadLocal<NLS> local = new InheritableThreadLocal<NLS>() { 75 protected NLS initialValue() { 76 return new NLS(Locale.getDefault()); 77 } 78 }; 79 80 /** 81 * Sets the locale for the calling thread. 82 * <p> 83 * The {@link #getBundleFor(Class)} method will honor this setting if if it 84 * is supported by the provided resource bundle property files. Otherwise, 85 * it will use a fall back locale as described in the 86 * {@link TranslationBundle} 87 * 88 * @param locale 89 * the preferred locale 90 */ 91 public static void setLocale(Locale locale) { 92 local.set(new NLS(locale)); 93 } 94 95 /** 96 * Sets the JVM default locale as the locale for the calling thread. 97 * <p> 98 * Semantically this is equivalent to <code>NLS.setLocale(Locale.getDefault())</code>. 99 */ 100 public static void useJVMDefaultLocale() { 101 local.set(new NLS(Locale.getDefault())); 102 } 103 104 /** 105 * Returns an instance of the translation bundle of the required type. All 106 * public String fields of the bundle instance will get their values 107 * injected as described in the {@link TranslationBundle}. 108 * 109 * @param <T> 110 * required bundle type 111 * @param type 112 * required bundle type 113 * @return an instance of the required bundle type 114 * @exception TranslationBundleLoadingException see {@link TranslationBundleLoadingException} 115 * @exception TranslationStringMissingException see {@link TranslationStringMissingException} 116 */ 117 public static <T extends TranslationBundle> T getBundleFor(Class<T> type) { 118 return local.get().get(type); 119 } 120 121 final private Locale locale; 122 final private ConcurrentHashMap<Class, TranslationBundle> map = new ConcurrentHashMap<Class, TranslationBundle>(); 123 124 private NLS(Locale locale) { 125 this.locale = locale; 126 } 127 128 @SuppressWarnings("unchecked") 129 private <T extends TranslationBundle> T get(Class<T> type) { 130 TranslationBundle bundle = map.get(type); 131 if (bundle == null) { 132 bundle = GlobalBundleCache.lookupBundle(locale, type); 133 // There is a small opportunity for a race, which we may 134 // lose. Accept defeat and return the winner's instance. 135 TranslationBundle old = map.putIfAbsent(type, bundle); 136 if (old != null) 137 bundle = old; 138 } 139 return (T) bundle; 140 } 141 }