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