libjava/java/nio/charset/spi/CharsetProvider.java

   1 /* CharsetProvider.java -- charset service provider interface
   2    Copyright (C) 2002 Free Software Foundation
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38 package java.nio.charset.spi;
  39
  40 import java.nio.charset.Charset;
  41 import java.util.Iterator;
  42
  43
  44 /**
  45  * This class allows an implementor to provide additional character sets. The
  46  * subclass must have a nullary constructor, and be attached to charset
  47  * implementation classes. These extensions are loaded via the context class
  48  * loader. To provide the charset extension, all files named
  49  * <code>META-INF/services/java.nio.charset.spi.CharsetProvider</code> are
  50  * read from the classpath. Each one should be a UTF-8 encoded list of
  51  * fully-qualified names of concrete subclasses of this class; whitespace is
  52  * ignored, and '#' starts comments. Duplicates are ignored. The
  53  * implementations must be accessible to the classloader that requests them.
  54  *
  55  * @author Eric Blake (ebb9@email.byu.edu)
  56  * @see Charset
  57  * @since 1.4
  58  * @status updated to 1.4
  59  */
  60 public abstract class CharsetProvider
  61 {
  62   /**
  63    * Initialize a new charset provider. This performs a security check on
  64    * RuntimePermission("charsetProvider").
  65    *
  66    * @throws SecurityException if building a new set is not allowed
  67    */
  68   protected CharsetProvider()
  69   {
  70     SecurityManager s = System.getSecurityManager();
  71     if (s != null)
  72       s.checkPermission(new RuntimePermission("charsetProvider"));
  73   }
  74
  75   /**
  76    * Returns an iterator over the charsets defined by this provider.
  77    *
  78    * @return the iterator
  79    * @see Charset#availableCharsets()
  80    */
  81   public abstract Iterator charsets();
  82
  83   /**
  84    * Returns the named charset, by canonical name or alias.
  85    *
  86    * @param name the name of the character
  87    *
  88    * @return the charset, or null if not supported
  89    */
  90   public abstract Charset charsetForName(String name);
  91 } // class CharsetProvider