001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.codec;
018
019import java.nio.charset.Charset;
020import java.nio.charset.StandardCharsets;
021
022/**
023 * Charsets required of every implementation of the Java platform.
024 *
025 * From the Java documentation <a href="https://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard
026 * charsets</a>:
027 * <p>
028 * <cite>Every implementation of the Java platform is required to support the following character encodings. Consult the
029 * release documentation for your implementation to see if any other encodings are supported. Consult the release
030 * documentation for your implementation to see if any other encodings are supported. </cite>
031 * </p>
032 *
033 * <ul>
034 * <li>{@code US-ASCII}<p>
035 * Seven-bit ASCII, a.k.a. ISO646-US, a.k.a. the Basic Latin block of the Unicode character set.</p></li>
036 * <li>{@code ISO-8859-1}<p>
037 * ISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1.</p></li>
038 * <li>{@code UTF-8}<p>
039 * Eight-bit Unicode Transformation Format.</p></li>
040 * <li>{@code UTF-16BE}<p>
041 * Sixteen-bit Unicode Transformation Format, big-endian byte order.</p></li>
042 * <li>{@code UTF-16LE}<p>
043 * Sixteen-bit Unicode Transformation Format, little-endian byte order.</p></li>
044 * <li>{@code UTF-16}<p>
045 * Sixteen-bit Unicode Transformation Format, byte order specified by a mandatory initial byte-order mark (either order
046 * accepted on input, big-endian used on output.)</p></li>
047 * </ul>
048 *
049 * This perhaps would best belong in the Commons Lang project. Even if a similar class is defined in Commons Lang, it is
050 * not foreseen that Commons Codec would be made to depend on Commons Lang.
051 *
052 * <p>
053 * This class is immutable and thread-safe.
054 * </p>
055 *
056 * @see <a href="https://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
057 * @since 1.7
058 */
059public class Charsets {
060
061    //
062    // This class should only contain Charset instances for required encodings. This guarantees that it will load
063    // correctly and without delay on all Java platforms.
064    //
065
066    /**
067     * CharEncodingISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1.
068     * <p>
069     * Every implementation of the Java platform is required to support this character encoding.
070     * </p>
071     *
072     * @deprecated Use {@link java.nio.charset.StandardCharsets#ISO_8859_1} instead.
073     * @see <a href="https://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
074     */
075    @Deprecated
076    public static final Charset ISO_8859_1 = StandardCharsets.ISO_8859_1;
077
078    /**
079     * Seven-bit ASCII, also known as ISO646-US, also known as the Basic Latin block of the Unicode character set.
080     * <p>
081     * Every implementation of the Java platform is required to support this character encoding.
082     * </p>
083     *
084     * @deprecated Use {@link java.nio.charset.StandardCharsets#US_ASCII} instead.
085     * @see <a href="https://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
086     */
087    @Deprecated
088    public static final Charset US_ASCII = StandardCharsets.US_ASCII;
089
090    /**
091     * Sixteen-bit Unicode Transformation Format, The byte order specified by a mandatory initial byte-order mark
092     * (either order accepted on input, big-endian used on output)
093     * <p>
094     * Every implementation of the Java platform is required to support this character encoding.
095     * </p>
096     *
097     * @deprecated Use {@link java.nio.charset.StandardCharsets#UTF_16} instead.
098     * @see <a href="https://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
099     */
100    @Deprecated
101    public static final Charset UTF_16 = StandardCharsets.UTF_16;
102
103    /**
104     * Sixteen-bit Unicode Transformation Format, big-endian byte order.
105     * <p>
106     * Every implementation of the Java platform is required to support this character encoding.
107     * </p>
108     *
109     * @deprecated Use {@link java.nio.charset.StandardCharsets#UTF_16BE} instead.
110     * @see <a href="https://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
111     */
112    @Deprecated
113    public static final Charset UTF_16BE = StandardCharsets.UTF_16BE;
114
115    /**
116     * Sixteen-bit Unicode Transformation Format, little-endian byte order.
117     * <p>
118     * Every implementation of the Java platform is required to support this character encoding.
119     * </p>
120     *
121     * @deprecated Use {@link java.nio.charset.StandardCharsets#UTF_16LE} instead.
122     * @see <a href="https://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
123     */
124    @Deprecated
125    public static final Charset UTF_16LE = StandardCharsets.UTF_16LE;
126
127    /**
128     * Eight-bit Unicode Transformation Format.
129     * <p>
130     * Every implementation of the Java platform is required to support this character encoding.
131     * </p>
132     *
133     * @deprecated Use {@link java.nio.charset.StandardCharsets#UTF_8} instead.
134     * @see <a href="https://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
135     */
136    @Deprecated
137    public static final Charset UTF_8 = StandardCharsets.UTF_8;
138
139    /**
140     * Returns the given Charset or the default Charset if the given Charset is null.
141     *
142     * @param charset
143     *            A charset or null.
144     * @return the given Charset or the default Charset if the given Charset is null
145     */
146    public static Charset toCharset(final Charset charset) {
147        return charset == null ? Charset.defaultCharset() : charset;
148    }
149
150    /**
151     * Returns a Charset for the named charset. If the name is null, return the default Charset.
152     *
153     * @param charset
154     *            The name of the requested charset, may be null.
155     * @return a Charset for the named charset
156     * @throws java.nio.charset.UnsupportedCharsetException
157     *             If the named charset is unavailable
158     */
159    public static Charset toCharset(final String charset) {
160        return charset == null ? Charset.defaultCharset() : Charset.forName(charset);
161    }
162
163    /**
164     * TODO Make private in 2.0.
165     *
166     * @deprecated TODO Make private in 2.0.
167     */
168    @Deprecated
169    public Charsets() {
170        // empty
171    }
172}