content: /*
   * 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.nio.charset.UnsupportedCharsetException;
  
  /**
   * 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: Charsets.java 1311751 2012-04-10 14:26:21Z ggregory $
   */
  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.
      //
  
      /**
       * 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(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 UnsupportedCharsetException
       *             If the named charset is unavailable
       */
      public static Charset toCharset(String charset) {
          return charset == null ? Charset.defaultCharset() : Charset.forName(charset);
      }
  
      /**
       * CharEncodingISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1. </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>
       */
      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>
       */
      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>
       */
      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>
       */
      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>
       */
      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>
       */
      public static final Charset UTF_8 = Charset.forName("UTF-8");
  }
  