| /* Provider.java -- |
| Copyright (C) 2002, 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package gnu.java.nio.charset; |
| |
| import java.nio.charset.Charset; |
| import java.nio.charset.spi.CharsetProvider; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.Iterator; |
| |
| /** |
| * Charset provider for the required charsets. Used by |
| * {@link Charset#charsetForName} and * {@link Charset#availableCharsets}. |
| * |
| * @author Jesse Rosenstock |
| * @author Robert Schuster (thebohemian@gmx.net) |
| * @see Charset |
| */ |
| public final class Provider extends CharsetProvider |
| { |
| private static Provider singleton; |
| |
| static |
| { |
| synchronized (Provider.class) |
| { |
| singleton = null; |
| } |
| } |
| |
| /** |
| * Map from charset name to charset canonical name. The strings |
| * are all lower-case to allow case-insensitive retrieval of |
| * Charset instances. |
| */ |
| private final HashMap canonicalNames; |
| |
| /** |
| * Map from lower-case canonical name to Charset. |
| * TODO: We may want to use soft references. We would then need to keep |
| * track of the class name to regenerate the object. |
| */ |
| private final HashMap charsets; |
| |
| private Provider () |
| { |
| canonicalNames = new HashMap (); |
| charsets = new HashMap (); |
| |
| // US-ASCII aka ISO646-US |
| addCharset (new US_ASCII ()); |
| |
| // ISO-8859-1 aka ISO-LATIN-1 |
| addCharset (new ISO_8859_1 ()); |
| |
| // UTF-8 |
| addCharset (new UTF_8 ()); |
| |
| // UTF-16BE |
| addCharset (new UTF_16BE ()); |
| |
| // UTF-16LE |
| addCharset (new UTF_16LE ()); |
| |
| // UTF-16 |
| addCharset (new UTF_16 ()); |
| } |
| |
| public Iterator charsets () |
| { |
| return Collections.unmodifiableCollection (charsets.values ()) |
| .iterator (); |
| } |
| |
| /** |
| * Returns a Charset instance by converting the given |
| * name to lower-case, looking up the canonical charset |
| * name and finally looking up the Charset with that name. |
| * |
| * <p>The lookup is therefore case-insensitive.</p> |
| * |
| * @returns The Charset having <code>charsetName</code> |
| * as its alias or null if no such Charset exist. |
| */ |
| public Charset charsetForName (String charsetName) |
| { |
| return (Charset) charsets.get(canonicalNames.get(charsetName.toLowerCase())); |
| } |
| |
| /** |
| * Puts a Charset under its canonical name into the 'charsets' map. |
| * Then puts a mapping from all its alias names to the canonical name. |
| * |
| * <p>All names are converted to lower-case</p>. |
| * |
| * @param cs |
| */ |
| private void addCharset (Charset cs) |
| { |
| String canonicalName = cs.name().toLowerCase(); |
| charsets.put (canonicalName, cs); |
| |
| /* Adds a mapping between the canonical name |
| * itself making a lookup using that name |
| * no special case. |
| */ |
| canonicalNames.put(canonicalName, canonicalName); |
| |
| for (Iterator i = cs.aliases ().iterator (); i.hasNext (); ) |
| canonicalNames.put (((String) i.next()).toLowerCase(), canonicalName); |
| } |
| |
| public static synchronized Provider provider () |
| { |
| if (singleton == null) |
| singleton = new Provider (); |
| return singleton; |
| } |
| } |