/* | |
* Licensed to the Apache Software Foundation (ASF) under one or more | |
* contributor license agreements. See the NOTICE file distributed with | |
* this work for additional information regarding copyright ownership. | |
* The ASF licenses this file to You under the Apache License, Version 2.0 | |
* (the "License"); you may not use this file except in compliance with | |
* the License. You may obtain a copy of the License at | |
* | |
* http://www.apache.org/licenses/LICENSE-2.0 | |
* | |
* Unless required by applicable law or agreed to in writing, software | |
* distributed under the License is distributed on an "AS IS" BASIS, | |
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
* See the License for the specific language governing permissions and | |
* limitations under the License. | |
*/ | |
package org.apache.commons.io; | |
import java.nio.charset.Charset; | |
import java.util.Collections; | |
import java.util.SortedMap; | |
import java.util.TreeMap; | |
/** | |
* Charsets required of every implementation of the Java platform. | |
* | |
* From the Java documentation <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html"> | |
* Standard charsets</a>: | |
* <p> | |
* <cite>Every implementation of the Java platform is required to support the following character encodings. Consult | |
* the release documentation for your implementation to see if any other encodings are supported. Consult the release | |
* documentation for your implementation to see if any other encodings are supported. </cite> | |
* </p> | |
* | |
* <ul> | |
* <li><code>US-ASCII</code><br> | |
* Seven-bit ASCII, a.k.a. ISO646-US, a.k.a. the Basic Latin block of the Unicode character set.</li> | |
* <li><code>ISO-8859-1</code><br> | |
* ISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1.</li> | |
* <li><code>UTF-8</code><br> | |
* Eight-bit Unicode Transformation Format.</li> | |
* <li><code>UTF-16BE</code><br> | |
* Sixteen-bit Unicode Transformation Format, big-endian byte order.</li> | |
* <li><code>UTF-16LE</code><br> | |
* Sixteen-bit Unicode Transformation Format, little-endian byte order.</li> | |
* <li><code>UTF-16</code><br> | |
* Sixteen-bit Unicode Transformation Format, byte order specified by a mandatory initial byte-order mark (either order | |
* accepted on input, big-endian used on output.)</li> | |
* </ul> | |
* | |
* @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> | |
* @since 2.3 | |
* @version $Id$ | |
*/ | |
public class Charsets { | |
// | |
// This class should only contain Charset instances for required encodings. This guarantees that it will load | |
// correctly and without delay on all Java platforms. | |
// | |
/** | |
* Constructs a sorted map from canonical charset names to charset objects required of every implementation of the | |
* Java platform. | |
* <p> | |
* From the Java documentation <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html"> | |
* Standard charsets</a>: | |
* </p> | |
* | |
* @return An immutable, case-insensitive map from canonical charset names to charset objects. | |
* @see Charset#availableCharsets() | |
* @since 2.5 | |
*/ | |
public static SortedMap<String, Charset> requiredCharsets() { | |
// maybe cache? | |
// TODO Re-implement on Java 7 to use java.nio.charset.StandardCharsets | |
final TreeMap<String, Charset> m = new TreeMap<String, Charset>(String.CASE_INSENSITIVE_ORDER); | |
m.put(ISO_8859_1.name(), ISO_8859_1); | |
m.put(US_ASCII.name(), US_ASCII); | |
m.put(UTF_16.name(), UTF_16); | |
m.put(UTF_16BE.name(), UTF_16BE); | |
m.put(UTF_16LE.name(), UTF_16LE); | |
m.put(UTF_8.name(), UTF_8); | |
return Collections.unmodifiableSortedMap(m); | |
} | |
/** | |
* Returns the given Charset or the default Charset if the given Charset is null. | |
* | |
* @param charset | |
* A charset or null. | |
* @return the given Charset or the default Charset if the given Charset is null | |
*/ | |
public static Charset toCharset(final Charset charset) { | |
return charset == null ? Charset.defaultCharset() : charset; | |
} | |
/** | |
* Returns a Charset for the named charset. If the name is null, return the default Charset. | |
* | |
* @param charset | |
* The name of the requested charset, may be null. | |
* @return a Charset for the named charset | |
* @throws java.nio.charset.UnsupportedCharsetException | |
* If the named charset is unavailable | |
*/ | |
public static Charset toCharset(final String charset) { | |
return charset == null ? Charset.defaultCharset() : Charset.forName(charset); | |
} | |
/** | |
* CharEncodingISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1. | |
* <p> | |
* Every implementation of the Java platform is required to support this character encoding. | |
* </p> | |
* | |
* @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> | |
* @deprecated Use Java 7's {@link java.nio.charset.StandardCharsets} | |
*/ | |
@Deprecated | |
public static final Charset ISO_8859_1 = Charset.forName("ISO-8859-1"); | |
/** | |
* <p> | |
* Seven-bit ASCII, also known as ISO646-US, also known as the Basic Latin block of the Unicode character set. | |
* </p> | |
* <p> | |
* Every implementation of the Java platform is required to support this character encoding. | |
* </p> | |
* | |
* @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> | |
* @deprecated Use Java 7's {@link java.nio.charset.StandardCharsets} | |
*/ | |
@Deprecated | |
public static final Charset US_ASCII = Charset.forName("US-ASCII"); | |
/** | |
* <p> | |
* Sixteen-bit Unicode Transformation Format, The byte order specified by a mandatory initial byte-order mark | |
* (either order accepted on input, big-endian used on output) | |
* </p> | |
* <p> | |
* Every implementation of the Java platform is required to support this character encoding. | |
* </p> | |
* | |
* @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> | |
* @deprecated Use Java 7's {@link java.nio.charset.StandardCharsets} | |
*/ | |
@Deprecated | |
public static final Charset UTF_16 = Charset.forName("UTF-16"); | |
/** | |
* <p> | |
* Sixteen-bit Unicode Transformation Format, big-endian byte order. | |
* </p> | |
* <p> | |
* Every implementation of the Java platform is required to support this character encoding. | |
* </p> | |
* | |
* @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> | |
* @deprecated Use Java 7's {@link java.nio.charset.StandardCharsets} | |
*/ | |
@Deprecated | |
public static final Charset UTF_16BE = Charset.forName("UTF-16BE"); | |
/** | |
* <p> | |
* Sixteen-bit Unicode Transformation Format, little-endian byte order. | |
* </p> | |
* <p> | |
* Every implementation of the Java platform is required to support this character encoding. | |
* </p> | |
* | |
* @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> | |
* @deprecated Use Java 7's {@link java.nio.charset.StandardCharsets} | |
*/ | |
@Deprecated | |
public static final Charset UTF_16LE = Charset.forName("UTF-16LE"); | |
/** | |
* <p> | |
* Eight-bit Unicode Transformation Format. | |
* </p> | |
* <p> | |
* Every implementation of the Java platform is required to support this character encoding. | |
* </p> | |
* | |
* @see <a href="http://docs.oracle.com/javase/6/docs/api/java/nio/charset/Charset.html">Standard charsets</a> | |
* @deprecated Use Java 7's {@link java.nio.charset.StandardCharsets} | |
*/ | |
@Deprecated | |
public static final Charset UTF_8 = Charset.forName("UTF-8"); | |
} |