UnsupportedCharset.java

/*
 *  UnsupportedCharset.java  a dummy codepage for cpdetector's CodepageProcessor 
 *  executable.
 * 
 *  Copyright (C) Achim Westermann, created on 20.07.2004, 12:17:13  
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 * 
 * The contents of this collection are subject to the Mozilla Public License Version 
 * 1.1 (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.mozilla.org/MPL/
 * 
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 * 
 * The Original Code is the cpDetector code in [sub] packages info.monitorenter and 
 * cpdetector. 
 * 
 * The Initial Developer of the Original Code is
 * Achim Westermann <achim.westermann@gmx.de>.
 * 
 * Portions created by the Initial Developer are Copyright (c) 2007 
 * the Initial Developer. All Rights Reserved.
 * 
 * Contributor(s):
 * 
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 * 
 * ***** END LICENSE BLOCK ***** * 
 *  
 * If you modify or optimize the code in a useful way please let me know.
 * Achim.Westermann@gmx.de
 *	
 */
package info.monitorenter.cpdetector.io;

import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

/**
 * <p>
 * A dummy charset that indicates an unknown charset. Nevertheless some indication of a encoding
 * definition has been found that is contained here. The system just does not support that codepage.
 * </p>
 * <p>
 * These instances are obtained by the static singleton retrieval call {@link #forName(String)}
 * which allows unique instances for a detected string.
 * </p>
 * 
 * @author <a href="mailto:Achim.Westermann@gmx.de">Achim Westermann</a>
 */
public class UnsupportedCharset
    extends Charset {

  /** The name of this unsupported charset. */
  private String m_name;

  /**
   * Singleton cache for the unsupported charsets (no need to instanciate the same unsupported
   * charset again and again).
   */
  private static Map<String, Charset> singletons = new HashMap<String, Charset>();

  /**
   * Singleton constructor.
   * <p>
   * 
   * @param name
   *          the detected name of the charset.
   */
  private UnsupportedCharset(String name) {
    super("unsupported", null);
  }

  public static Charset forName(String name) {
    Charset ret = (Charset) singletons.get(name);
    if (ret == null) {
      ret = new UnsupportedCharset(name);
      UnsupportedCharset.singletons.put(name, ret);
    }
    return ret;
  }

  /**
   * @see java.nio.charset.Charset#contains(java.nio.charset.Charset)
   */
  public boolean contains(Charset cs) {
    return false;
  }

  /**
   * @see java.nio.charset.Charset#newDecoder()
   */
  public CharsetDecoder newDecoder() {
    throw new UnsupportedOperationException(
        "This is no real Charset but a flag you should test for!");
  }

  /**
   * @see java.nio.charset.Charset#newEncoder()
   */
  public CharsetEncoder newEncoder() {
    throw new UnsupportedOperationException(
        "This is no real Charset but a flag you should test for!");
  }

  /**
   * @see java.nio.charset.Charset#displayName()
   */
  public String displayName() {
    return this.m_name;
  }

  /**
   * @see java.nio.charset.Charset#displayName(java.util.Locale)
   */
  public String displayName(Locale locale) {
    return this.m_name;

  }

}