1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.codec;
18
19 import java.nio.charset.Charset;
20 import java.nio.charset.StandardCharsets;
21
22 /**
23 * Charsets required of every implementation of the Java platform.
24 *
25 * From the Java documentation <a href="https://docs.oracle.com/javase/8/docs/api/java/nio/charset/Charset.html">Standard
26 * charsets</a>:
27 * <p>
28 * <cite>Every implementation of the Java platform is required to support the following character encodings. Consult the
29 * release documentation for your implementation to see if any other encodings are supported. Consult the release
30 * documentation for your implementation to see if any other encodings are supported. </cite>
31 * </p>
32 *
33 * <ul>
34 * <li>{@code US-ASCII}
35 * <p>
36 * Seven-bit ASCII, a.k.a. ISO646-US, a.k.a. the Basic Latin block of the Unicode character set.
37 * </p>
38 * </li>
39 * <li>{@code ISO-8859-1}
40 * <p>
41 * ISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1.
42 * </p>
43 * </li>
44 * <li>{@code UTF-8}
45 * <p>
46 * Eight-bit Unicode Transformation Format.
47 * </p>
48 * </li>
49 * <li>{@code UTF-16BE}
50 * <p>
51 * Sixteen-bit Unicode Transformation Format, big-endian byte order.
52 * </p>
53 * </li>
54 * <li>{@code UTF-16LE}
55 * <p>
56 * Sixteen-bit Unicode Transformation Format, little-endian byte order.
57 * </p>
58 * </li>
59 * <li>{@code UTF-16}
60 * <p>
61 * Sixteen-bit Unicode Transformation Format, byte order specified by a mandatory initial byte-order mark (either order
62 * accepted on input, big-endian used on output.)
63 * </p>
64 * </li>
65 * </ul>
66 *
67 * This perhaps would best belong in the Commons Lang project. Even if a similar class is defined in Commons Lang, it is
68 * not foreseen that Commons Codec would be made to depend on Commons Lang.
69 *
70 * <p>
71 * This class is immutable and thread-safe.
72 * </p>
73 *
74 * @see <a href="https://docs.oracle.com/javase/8/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
75 * @since 1.7
76 */
77 public class Charsets {
78
79 //
80 // This class should only contain Charset instances for required encodings. This guarantees that it will load
81 // correctly and without delay on all Java platforms.
82 //
83
84 /**
85 * CharEncodingISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1.
86 * <p>
87 * Every implementation of the Java platform is required to support this character encoding.
88 * </p>
89 *
90 * @see <a href="https://docs.oracle.com/javase/8/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
91 * @deprecated Use {@link java.nio.charset.StandardCharsets#ISO_8859_1} instead.
92 */
93 @Deprecated
94 public static final Charset ISO_8859_1 = StandardCharsets.ISO_8859_1;
95
96 /**
97 * Seven-bit ASCII, also known as ISO646-US, also known as the Basic Latin block of the Unicode character set.
98 * <p>
99 * Every implementation of the Java platform is required to support this character encoding.
100 * </p>
101 *
102 * @see <a href="https://docs.oracle.com/javase/8/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
103 * @deprecated Use {@link java.nio.charset.StandardCharsets#US_ASCII} instead.
104 */
105 @Deprecated
106 public static final Charset US_ASCII = StandardCharsets.US_ASCII;
107
108 /**
109 * Sixteen-bit Unicode Transformation Format, The byte order specified by a mandatory initial byte-order mark
110 * (either order accepted on input, big-endian used on output)
111 * <p>
112 * Every implementation of the Java platform is required to support this character encoding.
113 * </p>
114 *
115 * @see <a href="https://docs.oracle.com/javase/8/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
116 * @deprecated Use {@link java.nio.charset.StandardCharsets#UTF_16} instead.
117 */
118 @Deprecated
119 public static final Charset UTF_16 = StandardCharsets.UTF_16;
120
121 /**
122 * Sixteen-bit Unicode Transformation Format, big-endian byte order.
123 * <p>
124 * Every implementation of the Java platform is required to support this character encoding.
125 * </p>
126 *
127 * @see <a href="https://docs.oracle.com/javase/8/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
128 * @deprecated Use {@link java.nio.charset.StandardCharsets#UTF_16BE} instead.
129 */
130 @Deprecated
131 public static final Charset UTF_16BE = StandardCharsets.UTF_16BE;
132
133 /**
134 * Sixteen-bit Unicode Transformation Format, little-endian byte order.
135 * <p>
136 * Every implementation of the Java platform is required to support this character encoding.
137 * </p>
138 *
139 * @see <a href="https://docs.oracle.com/javase/8/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
140 * @deprecated Use {@link java.nio.charset.StandardCharsets#UTF_16LE} instead.
141 */
142 @Deprecated
143 public static final Charset UTF_16LE = StandardCharsets.UTF_16LE;
144
145 /**
146 * Eight-bit Unicode Transformation Format.
147 * <p>
148 * Every implementation of the Java platform is required to support this character encoding.
149 * </p>
150 *
151 * @see <a href="https://docs.oracle.com/javase/8/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
152 * @deprecated Use {@link java.nio.charset.StandardCharsets#UTF_8} instead.
153 */
154 @Deprecated
155 public static final Charset UTF_8 = StandardCharsets.UTF_8;
156
157 /**
158 * Returns the given Charset or the default Charset if the given Charset is null.
159 *
160 * @param charset
161 * A charset or null.
162 * @return The given Charset or the default Charset if the given Charset is null.
163 */
164 public static Charset toCharset(final Charset charset) {
165 return charset == null ? Charset.defaultCharset() : charset;
166 }
167
168 /**
169 * Returns a Charset for the named charset. If the name is null, return the default Charset.
170 *
171 * @param charset The name of the requested charset, may be null.
172 * @return A Charset for the named charset.
173 * @throws java.nio.charset.UnsupportedCharsetException Thrown if the named charset is unavailable.
174 */
175 public static Charset toCharset(final String charset) {
176 return charset == null ? Charset.defaultCharset() : Charset.forName(charset);
177 }
178
179 /**
180 * TODO Make private in 2.0.
181 *
182 * @deprecated TODO Make private in 2.0.
183 */
184 @Deprecated
185 public Charsets() {
186 // empty
187 }
188 }