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 */ 018 019 package org.apache.commons.compress.utils; 020 021 import java.nio.charset.Charset; 022 import java.nio.charset.UnsupportedCharsetException; 023 024 /** 025 * Charsets required of every implementation of the Java platform. 026 * 027 * From the Java documentation <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard 028 * charsets</a>: 029 * <p> 030 * <cite>Every implementation of the Java platform is required to support the following character encodings. Consult the 031 * release documentation for your implementation to see if any other encodings are supported. Consult the release 032 * documentation for your implementation to see if any other encodings are supported. </cite> 033 * </p> 034 * 035 * <ul> 036 * <li><code>US-ASCII</code><br/> 037 * Seven-bit ASCII, a.k.a. ISO646-US, a.k.a. the Basic Latin block of the Unicode character set.</li> 038 * <li><code>ISO-8859-1</code><br/> 039 * ISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1.</li> 040 * <li><code>UTF-8</code><br/> 041 * Eight-bit Unicode Transformation Format.</li> 042 * <li><code>UTF-16BE</code><br/> 043 * Sixteen-bit Unicode Transformation Format, big-endian byte order.</li> 044 * <li><code>UTF-16LE</code><br/> 045 * Sixteen-bit Unicode Transformation Format, little-endian byte order.</li> 046 * <li><code>UTF-16</code><br/> 047 * Sixteen-bit Unicode Transformation Format, byte order specified by a mandatory initial byte-order mark (either order 048 * accepted on input, big-endian used on output.)</li> 049 * </ul> 050 * 051 * This class best belongs in the Commons Lang or IO project. Even if a similar class is defined in another Commons component, it is 052 * not foreseen that Commons Compress would be made to depend on another Commons component. 053 * 054 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> 055 * @since 1.4 056 * @version $Id: Charsets.java 1309643 2012-04-05 04:01:32Z ggregory $ 057 */ 058 public class Charsets { 059 060 // 061 // This class should only contain Charset instances for required encodings. This guarantees that it will load correctly and 062 // without delay on all Java platforms. 063 // 064 065 /** 066 * Returns the given Charset or the default Charset if the given Charset is null. 067 * 068 * @param charset 069 * A charset or null. 070 * @return the given Charset or the default Charset if the given Charset is null 071 */ 072 public static Charset toCharset(Charset charset) { 073 return charset == null ? Charset.defaultCharset() : charset; 074 } 075 076 /** 077 * Returns a Charset for the named charset. If the name is null, return the default Charset. 078 * 079 * @param charset 080 * The name of the requested charset, may be null. 081 * @return a Charset for the named charset 082 * @throws UnsupportedCharsetException 083 * If the named charset is unavailable 084 */ 085 public static Charset toCharset(String charset) { 086 return charset == null ? Charset.defaultCharset() : Charset.forName(charset); 087 } 088 089 /** 090 * CharsetNamesISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1. </p> 091 * <p> 092 * Every implementation of the Java platform is required to support this character encoding. 093 * </p> 094 * 095 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> 096 */ 097 public static final Charset ISO_8859_1 = Charset.forName(CharsetNames.ISO_8859_1); 098 099 /** 100 * <p> 101 * Seven-bit ASCII, also known as ISO646-US, also known as the Basic Latin block of the Unicode character set. 102 * </p> 103 * <p> 104 * Every implementation of the Java platform is required to support this character encoding. 105 * </p> 106 * 107 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> 108 */ 109 public static final Charset US_ASCII = Charset.forName(CharsetNames.US_ASCII); 110 111 /** 112 * <p> 113 * Sixteen-bit Unicode Transformation Format, The byte order specified by a mandatory initial byte-order mark 114 * (either order accepted on input, big-endian used on output) 115 * </p> 116 * <p> 117 * Every implementation of the Java platform is required to support this character encoding. 118 * </p> 119 * 120 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> 121 */ 122 public static final Charset UTF_16 = Charset.forName(CharsetNames.UTF_16); 123 124 /** 125 * <p> 126 * Sixteen-bit Unicode Transformation Format, big-endian byte order. 127 * </p> 128 * <p> 129 * Every implementation of the Java platform is required to support this character encoding. 130 * </p> 131 * 132 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> 133 */ 134 public static final Charset UTF_16BE = Charset.forName(CharsetNames.UTF_16BE); 135 136 /** 137 * <p> 138 * Sixteen-bit Unicode Transformation Format, little-endian byte order. 139 * </p> 140 * <p> 141 * Every implementation of the Java platform is required to support this character encoding. 142 * </p> 143 * 144 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> 145 */ 146 public static final Charset UTF_16LE = Charset.forName(CharsetNames.UTF_16LE); 147 148 /** 149 * <p> 150 * Eight-bit Unicode Transformation Format. 151 * </p> 152 * <p> 153 * Every implementation of the Java platform is required to support this character encoding. 154 * </p> 155 * 156 * @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> 157 */ 158 public static final Charset UTF_8 = Charset.forName(CharsetNames.UTF_8); 159 }