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.lang.reflect.InvocationTargetException;
47 import java.util.HashMap;
48 import java.util.Locale;
49 import java.util.Map;
50
51 import org.eclipse.jgit.errors.TranslationBundleLoadingException;
52 import org.eclipse.jgit.errors.TranslationStringMissingException;
53
54 /**
55 * Global cache of translation bundles.
56 * <p>
57 * Every translation bundle will be cached here when it gets loaded for the
58 * first time from a thread. Another lookup for the same translation bundle
59 * (same locale and type) from the same or a different thread will return the
60 * cached one.
61 * <p>
62 * Note that NLS instances maintain per-thread Map of loaded translation
63 * bundles. Once a thread accesses a translation bundle it will keep reference
64 * to it and will not call {@link #lookupBundle(Locale, Class)} again for the
65 * same translation bundle as long as its locale doesn't change.
66 */
67 class GlobalBundleCache {
68 private static final Map<Locale, Map<Class, TranslationBundle>> cachedBundles
69 = new HashMap<>();
70
71 /**
72 * Looks up for a translation bundle in the global cache. If found returns
73 * the cached bundle. If not found creates a new instance puts it into the
74 * cache and returns it.
75 *
76 * @param <T>
77 * required bundle type
78 * @param locale
79 * the preferred locale
80 * @param type
81 * required bundle type
82 * @return an instance of the required bundle type
83 * @exception TranslationBundleLoadingException see {@link TranslationBundle#load(Locale)}
84 * @exception TranslationStringMissingException see {@link TranslationBundle#load(Locale)}
85 */
86 @SuppressWarnings("unchecked")
87 static synchronized <T extends TranslationBundle> T lookupBundle(Locale locale, Class<T> type) {
88 try {
89 Map<Class, TranslationBundle> bundles = cachedBundles.get(locale);
90 if (bundles == null) {
91 bundles = new HashMap<>();
92 cachedBundles.put(locale, bundles);
93 }
94 TranslationBundle bundle = bundles.get(type);
95 if (bundle == null) {
96 bundle = type.getDeclaredConstructor().newInstance();
97 bundle.load(locale);
98 bundles.put(type, bundle);
99 }
100 return (T) bundle;
101 } catch (InstantiationException | IllegalAccessException
102 | InvocationTargetException | NoSuchMethodException e) {
103 throw new Error(e);
104 }
105 }
106 }