J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2004 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.nio.cs; |
| 27 | |
| 28 | import java.lang.ref.SoftReference; |
| 29 | import java.nio.charset.Charset; |
| 30 | import java.nio.charset.spi.CharsetProvider; |
| 31 | import java.util.ArrayList; |
| 32 | import java.util.TreeMap; |
| 33 | import java.util.Iterator; |
| 34 | import java.util.Locale; |
| 35 | import java.util.Map; |
| 36 | import sun.misc.ASCIICaseInsensitiveComparator; |
| 37 | |
| 38 | |
| 39 | /** |
| 40 | * Abstract base class for charset providers. |
| 41 | * |
| 42 | * @author Mark Reinhold |
| 43 | */ |
| 44 | |
| 45 | public class AbstractCharsetProvider |
| 46 | extends CharsetProvider |
| 47 | { |
| 48 | |
| 49 | /* Maps canonical names to class names |
| 50 | */ |
| 51 | private Map classMap |
| 52 | = new TreeMap(ASCIICaseInsensitiveComparator.CASE_INSENSITIVE_ORDER); |
| 53 | |
| 54 | /* Maps alias names to canonical names |
| 55 | */ |
| 56 | private Map aliasMap |
| 57 | = new TreeMap(ASCIICaseInsensitiveComparator.CASE_INSENSITIVE_ORDER); |
| 58 | |
| 59 | /* Maps canonical names to alias-name arrays |
| 60 | */ |
| 61 | private Map aliasNameMap |
| 62 | = new TreeMap(ASCIICaseInsensitiveComparator.CASE_INSENSITIVE_ORDER); |
| 63 | |
| 64 | /* Maps canonical names to soft references that hold cached instances |
| 65 | */ |
| 66 | private Map cache |
| 67 | = new TreeMap(ASCIICaseInsensitiveComparator.CASE_INSENSITIVE_ORDER); |
| 68 | |
| 69 | private String packagePrefix; |
| 70 | |
| 71 | protected AbstractCharsetProvider() { |
| 72 | packagePrefix = "sun.nio.cs"; |
| 73 | } |
| 74 | |
| 75 | protected AbstractCharsetProvider(String pkgPrefixName) { |
| 76 | packagePrefix = pkgPrefixName; |
| 77 | } |
| 78 | |
| 79 | /* Add an entry to the given map, but only if no mapping yet exists |
| 80 | * for the given name. |
| 81 | */ |
| 82 | private static void put(Map m, String name, Object value) { |
| 83 | if (!m.containsKey(name)) |
| 84 | m.put(name, value); |
| 85 | } |
| 86 | |
| 87 | private static void remove(Map m, String name) { |
| 88 | Object x = m.remove(name); |
| 89 | assert (x != null); |
| 90 | } |
| 91 | |
| 92 | /* Declare support for the given charset |
| 93 | */ |
| 94 | protected void charset(String name, String className, String[] aliases) { |
| 95 | synchronized (this) { |
| 96 | put(classMap, name, className); |
| 97 | for (int i = 0; i < aliases.length; i++) |
| 98 | put(aliasMap, aliases[i], name); |
| 99 | put(aliasNameMap, name, aliases); |
| 100 | cache.clear(); |
| 101 | } |
| 102 | } |
| 103 | |
| 104 | protected void deleteCharset(String name, String[] aliases) { |
| 105 | synchronized (this) { |
| 106 | remove(classMap, name); |
| 107 | for (int i = 0; i < aliases.length; i++) |
| 108 | remove(aliasMap, aliases[i]); |
| 109 | remove(aliasNameMap, name); |
| 110 | cache.clear(); |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | /* Late initialization hook, needed by some providers |
| 115 | */ |
| 116 | protected void init() { } |
| 117 | |
| 118 | private String canonicalize(String charsetName) { |
| 119 | String acn = (String)aliasMap.get(charsetName); |
| 120 | return (acn != null) ? acn : charsetName; |
| 121 | } |
| 122 | |
| 123 | private Charset lookup(String csn) { |
| 124 | |
| 125 | // Check cache first |
| 126 | SoftReference sr = (SoftReference)cache.get(csn); |
| 127 | if (sr != null) { |
| 128 | Charset cs = (Charset)sr.get(); |
| 129 | if (cs != null) |
| 130 | return cs; |
| 131 | } |
| 132 | |
| 133 | // Do we even support this charset? |
| 134 | String cln = (String)classMap.get(csn); |
| 135 | |
| 136 | if (cln == null) |
| 137 | return null; |
| 138 | |
| 139 | // Instantiate the charset and cache it |
| 140 | try { |
| 141 | |
| 142 | Class c = Class.forName(packagePrefix + "." + cln, |
| 143 | true, |
| 144 | this.getClass().getClassLoader()); |
| 145 | |
| 146 | Charset cs = (Charset)c.newInstance(); |
| 147 | cache.put(csn, new SoftReference(cs)); |
| 148 | return cs; |
| 149 | } catch (ClassNotFoundException x) { |
| 150 | return null; |
| 151 | } catch (IllegalAccessException x) { |
| 152 | return null; |
| 153 | } catch (InstantiationException x) { |
| 154 | return null; |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | public final Charset charsetForName(String charsetName) { |
| 159 | synchronized (this) { |
| 160 | init(); |
| 161 | return lookup(canonicalize(charsetName)); |
| 162 | } |
| 163 | } |
| 164 | |
| 165 | public final Iterator<Charset> charsets() { |
| 166 | |
| 167 | final ArrayList ks; |
| 168 | synchronized (this) { |
| 169 | init(); |
| 170 | ks = new ArrayList(classMap.keySet()); |
| 171 | } |
| 172 | |
| 173 | return new Iterator<Charset>() { |
| 174 | Iterator i = ks.iterator(); |
| 175 | |
| 176 | public boolean hasNext() { |
| 177 | return i.hasNext(); |
| 178 | } |
| 179 | |
| 180 | public Charset next() { |
| 181 | String csn = (String)i.next(); |
| 182 | return lookup(csn); |
| 183 | } |
| 184 | |
| 185 | public void remove() { |
| 186 | throw new UnsupportedOperationException(); |
| 187 | } |
| 188 | }; |
| 189 | } |
| 190 | |
| 191 | public final String[] aliases(String charsetName) { |
| 192 | synchronized (this) { |
| 193 | init(); |
| 194 | return (String[])aliasNameMap.get(charsetName); |
| 195 | } |
| 196 | } |
| 197 | |
| 198 | } |