/* * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code 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 * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package sun.nio.cs; import java.lang.ref.SoftReference;import java.nio.charset.Charset;import java.nio.charset.spi.CharsetProvider;import java.util.ArrayList;import java.util.TreeMap;import java.util.Iterator;import java.util.Locale;import java.util.Map;import sun.misc.ASCIICaseInsensitiveComparator;  /** * Abstract base class for charset providers. * * @author Mark Reinhold */ public class AbstractCharsetProvider    extends CharsetProvider{     /* Maps canonical names to class names     */    private Map<String,String> classMap        = new TreeMap<>(ASCIICaseInsensitiveComparator.CASE_INSENSITIVE_ORDER);     /* Maps alias names to canonical names     */    private Map<String,String> aliasMap        = new TreeMap<>(ASCIICaseInsensitiveComparator.CASE_INSENSITIVE_ORDER);     /* Maps canonical names to alias-name arrays     */    private Map<String,String[]> aliasNameMap        = new TreeMap<>(ASCIICaseInsensitiveComparator.CASE_INSENSITIVE_ORDER);     /* Maps canonical names to soft references that hold cached instances     */    private Map<String,SoftReference<Charset>> cache        = new TreeMap<>(ASCIICaseInsensitiveComparator.CASE_INSENSITIVE_ORDER);     private String packagePrefix;     protected AbstractCharsetProvider() {        packagePrefix = "sun.nio.cs";    }     protected AbstractCharsetProvider(String pkgPrefixName) {        packagePrefix = pkgPrefixName;    }     /* Add an entry to the given map, but only if no mapping yet exists     * for the given name.     */    private static <K,V> void put(Map<K,V> m, K name, V value) {        if (!m.containsKey(name))            m.put(name, value);    }     private static <K,V> void remove(Map<K,V> m, K name) {        V x  = m.remove(name);        assert (x != null);    }     /* Declare support for the given charset     */    protected void charset(String name, String className, String[] aliases) {        synchronized (this) {            put(classMap, name, className);            for (int i = 0; i < aliases.length; i++)                put(aliasMap, aliases[i], name);            put(aliasNameMap, name, aliases);            cache.clear();        }    }     protected void deleteCharset(String name, String[] aliases) {        synchronized (this) {            remove(classMap, name);            for (int i = 0; i < aliases.length; i++)                remove(aliasMap, aliases[i]);            remove(aliasNameMap, name);            cache.clear();        }    }     /* Late initialization hook, needed by some providers     */    protected void init() { }     private String canonicalize(String charsetName) {        String acn = aliasMap.get(charsetName);        return (acn != null) ? acn : charsetName;    }     private Charset lookup(String csn) {         // Check cache first        SoftReference<Charset> sr = cache.get(csn);        if (sr != null) {            Charset cs = sr.get();            if (cs != null)                return cs;        }         // Do we even support this charset?        String cln = classMap.get(csn);         if (cln == null)            return null;         // Instantiate the charset and cache it        try {             Class<?> c = Class.forName(packagePrefix + "." + cln,                                       true,                                       this.getClass().getClassLoader());             Charset cs = (Charset)c.newInstance();            cache.put(csn, new SoftReference<Charset>(cs));            return cs;        } catch (ClassNotFoundException x) {            return null;        } catch (IllegalAccessException x) {            return null;        } catch (InstantiationException x) {            return null;        }    }     public final Charset charsetForName(String charsetName) {        synchronized (this) {            init();            return lookup(canonicalize(charsetName));        }    }     public final Iterator<Charset> charsets() {         final ArrayList<String> ks;        synchronized (this) {            init();            ks = new ArrayList<>(classMap.keySet());        }         return new Iterator<Charset>() {                Iterator<String> i = ks.iterator();                 public boolean hasNext() {                    return i.hasNext();                }                 public Charset next() {                    String csn = i.next();                    return lookup(csn);                }                 public void remove() {                    throw new UnsupportedOperationException();                }            };    }     public final String[] aliases(String charsetName) {        synchronized (this) {            init();            return aliasNameMap.get(charsetName);        }    } }