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My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

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java/pkg/java/util/spi/LocaleServiceProvider.java+138−0
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1+/*
2+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
3+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4+ *
5+ * This code is free software; you can redistribute it and/or modify it
6+ * under the terms of the GNU General Public License version 2 only, as
7+ * published by the Free Software Foundation. Oracle designates this
8+ * particular file as subject to the "Classpath" exception as provided
9+ * by Oracle in the LICENSE file that accompanied this code.
10+ *
11+ * This code is distributed in the hope that it will be useful, but WITHOUT
12+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14+ * version 2 for more details (a copy is included in the LICENSE file that
15+ * accompanied this code).
16+ *
17+ * You should have received a copy of the GNU General Public License version
18+ * 2 along with this work; if not, write to the Free Software Foundation,
19+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20+ *
21+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22+ * or visit www.oracle.com if you need additional information or have any
23+ * questions.
24+ */
25+
26+package java.util.spi;
27+
28+import java.util.Locale;
29+
30+/**
31+ * <p>
32+ * This is the super class of all the locale sensitive service provider
33+ * interfaces (SPIs).
34+ * <p>
35+ * Locale sensitive service provider interfaces are interfaces that
36+ * correspond to locale sensitive classes in the <code>java.text</code>
37+ * and <code>java.util</code> packages. The interfaces enable the
38+ * construction of locale sensitive objects and the retrieval of
39+ * localized names for these packages. Locale sensitive factory methods
40+ * and methods for name retrieval in the <code>java.text</code> and
41+ * <code>java.util</code> packages use implementations of the provider
42+ * interfaces to offer support for locales beyond the set of locales
43+ * supported by the Java runtime environment itself.
44+ * <p>
45+ * <h4>Packaging of Locale Sensitive Service Provider Implementations</h4>
46+ * Implementations of these locale sensitive services are packaged using the
47+ * <a href="../../../../technotes/guides/extensions/index.html">Java Extension Mechanism</a>
48+ * as installed extensions. A provider identifies itself with a
49+ * provider-configuration file in the resource directory META-INF/services,
50+ * using the fully qualified provider interface class name as the file name.
51+ * The file should contain a list of fully-qualified concrete provider class names,
52+ * one per line. A line is terminated by any one of a line feed ('\n'), a carriage
53+ * return ('\r'), or a carriage return followed immediately by a line feed. Space
54+ * and tab characters surrounding each name, as well as blank lines, are ignored.
55+ * The comment character is '#' ('\u0023'); on each line all characters following
56+ * the first comment character are ignored. The file must be encoded in UTF-8.
57+ * <p>
58+ * If a particular concrete provider class is named in more than one configuration
59+ * file, or is named in the same configuration file more than once, then the
60+ * duplicates will be ignored. The configuration file naming a particular provider
61+ * need not be in the same jar file or other distribution unit as the provider itself.
62+ * The provider must be accessible from the same class loader that was initially
63+ * queried to locate the configuration file; this is not necessarily the class loader
64+ * that loaded the file.
65+ * <p>
66+ * For example, an implementation of the
67+ * {@link java.text.spi.DateFormatProvider DateFormatProvider} class should
68+ * take the form of a jar file which contains the file:
69+ * <pre>
70+ * META-INF/services/java.text.spi.DateFormatProvider
71+ * </pre>
72+ * And the file <code>java.text.spi.DateFormatProvider</code> should have
73+ * a line such as:
74+ * <pre>
75+ * <code>com.foo.DateFormatProviderImpl</code>
76+ * </pre>
77+ * which is the fully qualified class name of the class implementing
78+ * <code>DateFormatProvider</code>.
79+ * <h4>Invocation of Locale Sensitive Services</h4>
80+ * <p>
81+ * Locale sensitive factory methods and methods for name retrieval in the
82+ * <code>java.text</code> and <code>java.util</code> packages invoke
83+ * service provider methods when needed to support the requested locale.
84+ * The methods first check whether the Java runtime environment itself
85+ * supports the requested locale, and use its support if available.
86+ * Otherwise, they call the <code>getAvailableLocales()</code> methods of
87+ * installed providers for the appropriate interface to find one that
88+ * supports the requested locale. If such a provider is found, its other
89+ * methods are called to obtain the requested object or name. When checking
90+ * whether a locale is supported, the locale's extensions are ignored.
91+ * If neither the Java runtime environment itself nor an installed provider
92+ * supports the requested locale, the methods go through a list of candidate
93+ * locales and repeat the availability check for each until a match is found.
94+ * The algorithm used for creating a list of candidate locales is same as
95+ * the one used by <code>ResourceBunlde</code> by default (see
96+ * {@link java.util.ResourceBundle.Control#getCandidateLocales getCandidateLocales}
97+ * for the details). Even if a locale is resolved from the candidate list,
98+ * methods that return requested objects or names are invoked with the original
99+ * requested locale including extensions. The Java runtime environment must
100+ * support the root locale for all locale sensitive services in order to
101+ * guarantee that this process terminates.
102+ * <p>
103+ * Providers of names (but not providers of other objects) are allowed to
104+ * return null for some name requests even for locales that they claim to
105+ * support by including them in their return value for
106+ * <code>getAvailableLocales</code>. Similarly, the Java runtime
107+ * environment itself may not have all names for all locales that it
108+ * supports. This is because the sets of objects for which names are
109+ * requested can be large and vary over time, so that it's not always
110+ * feasible to cover them completely. If the Java runtime environment or a
111+ * provider returns null instead of a name, the lookup will proceed as
112+ * described above as if the locale was not supported.
113+ *
114+ * @since 1.6
115+ */
116+public abstract class LocaleServiceProvider {
117+
118+ /**
119+ * Sole constructor. (For invocation by subclass constructors, typically
120+ * implicit.)
121+ */
122+ protected LocaleServiceProvider() {
123+ }
124+
125+ /**
126+ * Returns an array of all locales for which this locale service provider
127+ * can provide localized objects or names.
128+ * <p>
129+ * <b>Note:</b> Extensions in a <code>Locale</code> are ignored during
130+ * service provider lookup. So the array returned by this method should
131+ * not include two or more <code>Locale</code> objects only differing in
132+ * their extensions.
133+ *
134+ * @return An array of all locales for which this locale service provider
135+ * can provide localized objects or names.
136+ */
137+ public abstract Locale[] getAvailableLocales();
138+}