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/*
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* Copyright 2001 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Sun designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Sun in the LICENSE file that accompanied this code.
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*/
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package sun.nio.cs;
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import java.nio.*;
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import java.nio.charset.*;
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public class ThreadLocalCoders {
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private static final int CACHE_SIZE = 3;
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private static abstract class Cache {
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// Thread-local reference to array of cached objects, in LRU order
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private ThreadLocal cache = new ThreadLocal();
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private final int size;
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Cache(int size) {
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this.size = size;
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}
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abstract Object create(Object name);
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private void moveToFront(Object[] oa, int i) {
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Object ob = oa[i];
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for (int j = i; j > 0; j--)
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oa[j] = oa[j - 1];
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oa[0] = ob;
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abstract boolean hasName(Object ob, Object name);
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Object forName(Object name) {
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Object[] oa = (Object[])cache.get();
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if (oa == null) {
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oa = new Object[size];
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cache.set(oa);
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} else {
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for (int i = 0; i < oa.length; i++) {
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if (ob == null)
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continue;
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if (hasName(ob, name)) {
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if (i > 0)
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moveToFront(oa, i);
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return ob;
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// Create a new object
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Object ob = create(name);
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oa[oa.length - 1] = ob;
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moveToFront(oa, oa.length - 1);
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private static Cache decoderCache = new Cache(CACHE_SIZE) {
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boolean hasName(Object ob, Object name) {
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if (name instanceof String)
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return (((CharsetDecoder)ob).charset().name().equals(name));
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if (name instanceof Charset)
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return ((CharsetDecoder)ob).charset().equals(name);
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return false;
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Object create(Object name) {
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return Charset.forName((String)name).newDecoder();
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return ((Charset)name).newDecoder();
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assert false;
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return null;
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};
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public static CharsetDecoder decoderFor(Object name) {
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CharsetDecoder cd = (CharsetDecoder)decoderCache.forName(name);
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cd.reset();
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return cd;
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private static Cache encoderCache = new Cache(CACHE_SIZE) {
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return (((CharsetEncoder)ob).charset().name().equals(name));
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return ((CharsetEncoder)ob).charset().equals(name);
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return Charset.forName((String)name).newEncoder();
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return ((Charset)name).newEncoder();
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public static CharsetEncoder encoderFor(Object name) {
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CharsetEncoder ce = (CharsetEncoder)encoderCache.forName(name);
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ce.reset();
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return ce;
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