J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 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.Iterator; |
| 32 | import java.util.Map; |
| 33 | |
| 34 | |
| 35 | /** |
| 36 | * Abstract base class for fast charset providers. |
| 37 | * |
| 38 | * @author Mark Reinhold |
| 39 | */ |
| 40 | |
| 41 | public class FastCharsetProvider |
| 42 | extends CharsetProvider |
| 43 | { |
| 44 | |
| 45 | // Maps canonical names to class names |
| 46 | private Map<String,String> classMap; |
| 47 | |
| 48 | // Maps alias names to canonical names |
| 49 | private Map<String,String> aliasMap; |
| 50 | |
| 51 | // Maps canonical names to cached instances |
| 52 | private Map<String,Charset> cache; |
| 53 | |
| 54 | private String packagePrefix; |
| 55 | |
| 56 | protected FastCharsetProvider(String pp, |
| 57 | Map<String,String> am, |
| 58 | Map<String,String> cm, |
| 59 | Map<String,Charset> c) |
| 60 | { |
| 61 | packagePrefix = pp; |
| 62 | aliasMap = am; |
| 63 | classMap = cm; |
| 64 | cache = c; |
| 65 | } |
| 66 | |
| 67 | private String canonicalize(String csn) { |
| 68 | String acn = aliasMap.get(csn); |
| 69 | return (acn != null) ? acn : csn; |
| 70 | } |
| 71 | |
| 72 | // Private ASCII-only version, optimized for interpretation during startup |
| 73 | // |
| 74 | private static String toLower(String s) { |
| 75 | int n = s.length(); |
| 76 | boolean allLower = true; |
| 77 | for (int i = 0; i < n; i++) { |
| 78 | int c = s.charAt(i); |
| 79 | if (((c - 'A') | ('Z' - c)) >= 0) { |
| 80 | allLower = false; |
| 81 | break; |
| 82 | } |
| 83 | } |
| 84 | if (allLower) |
| 85 | return s; |
| 86 | char[] ca = new char[n]; |
| 87 | for (int i = 0; i < n; i++) { |
| 88 | int c = s.charAt(i); |
| 89 | if (((c - 'A') | ('Z' - c)) >= 0) |
| 90 | ca[i] = (char)(c + 0x20); |
| 91 | else |
| 92 | ca[i] = (char)c; |
| 93 | } |
| 94 | return new String(ca); |
| 95 | } |
| 96 | |
| 97 | private Charset lookup(String charsetName) { |
| 98 | |
| 99 | String csn = canonicalize(toLower(charsetName)); |
| 100 | |
| 101 | // Check cache first |
| 102 | Charset cs = cache.get(csn); |
| 103 | if (cs != null) |
| 104 | return cs; |
| 105 | |
| 106 | // Do we even support this charset? |
| 107 | String cln = classMap.get(csn); |
| 108 | if (cln == null) |
| 109 | return null; |
| 110 | |
| 111 | if (cln.equals("US_ASCII")) { |
| 112 | cs = new US_ASCII(); |
| 113 | cache.put(csn, cs); |
| 114 | return cs; |
| 115 | } |
| 116 | |
| 117 | // Instantiate the charset and cache it |
| 118 | try { |
| 119 | Class c = Class.forName(packagePrefix + "." + cln, |
| 120 | true, |
| 121 | this.getClass().getClassLoader()); |
| 122 | cs = (Charset)c.newInstance(); |
| 123 | cache.put(csn, cs); |
| 124 | return cs; |
| 125 | } catch (ClassNotFoundException x) { |
| 126 | return null; |
| 127 | } catch (IllegalAccessException x) { |
| 128 | return null; |
| 129 | } catch (InstantiationException x) { |
| 130 | return null; |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | public final Charset charsetForName(String charsetName) { |
| 135 | synchronized (this) { |
| 136 | return lookup(canonicalize(charsetName)); |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | public final Iterator<Charset> charsets() { |
| 141 | |
| 142 | return new Iterator<Charset>() { |
| 143 | |
| 144 | Iterator<String> i = classMap.keySet().iterator(); |
| 145 | |
| 146 | public boolean hasNext() { |
| 147 | return i.hasNext(); |
| 148 | } |
| 149 | |
| 150 | public Charset next() { |
| 151 | String csn = i.next(); |
| 152 | return lookup(csn); |
| 153 | } |
| 154 | |
| 155 | public void remove() { |
| 156 | throw new UnsupportedOperationException(); |
| 157 | } |
| 158 | |
| 159 | }; |
| 160 | |
| 161 | } |
| 162 | |
| 163 | } |