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 */
017 package org.apache.commons.io;
018
019 import java.nio.charset.Charset;
020 import java.nio.charset.UnsupportedCharsetException;
021
022 /**
023 * Charsets required of every implementation of the Java platform.
024 *
025 * From the Java documentation <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">
026 * Standard 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</code><br/>
035 * Seven-bit ASCII, a.k.a. ISO646-US, a.k.a. the Basic Latin block of the Unicode character set.</li>
036 * <li><code>ISO-8859-1</code><br/>
037 * ISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1.</li>
038 * <li><code>UTF-8</code><br/>
039 * Eight-bit Unicode Transformation Format.</li>
040 * <li><code>UTF-16BE</code><br/>
041 * Sixteen-bit Unicode Transformation Format, big-endian byte order.</li>
042 * <li><code>UTF-16LE</code><br/>
043 * Sixteen-bit Unicode Transformation Format, little-endian byte order.</li>
044 * <li><code>UTF-16</code><br/>
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.)</li>
047 * </ul>
048 *
049 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
050 * @since 2.3
051 * @version $Id: Charsets.java 1311751 2012-04-10 14:26:21Z ggregory $
052 */
053 public class Charsets {
054 //
055 // This class should only contain Charset instances for required encodings. This guarantees that it will load
056 // correctly and without delay on all Java platforms.
057 //
058
059 /**
060 * Returns the given Charset or the default Charset if the given Charset is null.
061 *
062 * @param charset
063 * A charset or null.
064 * @return the given Charset or the default Charset if the given Charset is null
065 */
066 public static Charset toCharset(Charset charset) {
067 return charset == null ? Charset.defaultCharset() : charset;
068 }
069
070 /**
071 * Returns a Charset for the named charset. If the name is null, return the default Charset.
072 *
073 * @param charset
074 * The name of the requested charset, may be null.
075 * @return a Charset for the named charset
076 * @throws UnsupportedCharsetException
077 * If the named charset is unavailable
078 */
079 public static Charset toCharset(String charset) {
080 return charset == null ? Charset.defaultCharset() : Charset.forName(charset);
081 }
082
083 /**
084 * CharEncodingISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1. </p>
085 * <p>
086 * Every implementation of the Java platform is required to support this character encoding.
087 * </p>
088 *
089 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
090 */
091 public static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
092
093 /**
094 * <p>
095 * Seven-bit ASCII, also known as ISO646-US, also known as the Basic Latin block of the Unicode character set.
096 * </p>
097 * <p>
098 * Every implementation of the Java platform is required to support this character encoding.
099 * </p>
100 *
101 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
102 */
103 public static final Charset US_ASCII = Charset.forName("US-ASCII");
104
105 /**
106 * <p>
107 * Sixteen-bit Unicode Transformation Format, The byte order specified by a mandatory initial byte-order mark
108 * (either order accepted on input, big-endian used on output)
109 * </p>
110 * <p>
111 * Every implementation of the Java platform is required to support this character encoding.
112 * </p>
113 *
114 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
115 */
116 public static final Charset UTF_16 = Charset.forName("UTF-16");
117
118 /**
119 * <p>
120 * Sixteen-bit Unicode Transformation Format, big-endian byte order.
121 * </p>
122 * <p>
123 * Every implementation of the Java platform is required to support this character encoding.
124 * </p>
125 *
126 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
127 */
128 public static final Charset UTF_16BE = Charset.forName("UTF-16BE");
129
130 /**
131 * <p>
132 * Sixteen-bit Unicode Transformation Format, little-endian byte order.
133 * </p>
134 * <p>
135 * Every implementation of the Java platform is required to support this character encoding.
136 * </p>
137 *
138 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
139 */
140 public static final Charset UTF_16LE = Charset.forName("UTF-16LE");
141
142 /**
143 * <p>
144 * Eight-bit Unicode Transformation Format.
145 * </p>
146 * <p>
147 * Every implementation of the Java platform is required to support this character encoding.
148 * </p>
149 *
150 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a>
151 */
152 public static final Charset UTF_8 = Charset.forName("UTF-8");
153 }