/* * Copyright (c) 2001, 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.nio.*;import java.nio.charset.*;  /** * Utility class for caching per-thread decoders and encoders. */ public class ThreadLocalCoders {     private static final int CACHE_SIZE = 3;     private static abstract class Cache {         // Thread-local reference to array of cached objects, in LRU order        private ThreadLocal cache = new ThreadLocal();        private final int size;         Cache(int size) {            this.size = size;        }         abstract Object create(Object name);         private void moveToFront(Object[] oa, int i) {            Object ob = oa[i];            for (int j = i; j > 0; j--)                oa[j] = oa[j - 1];            oa[0] = ob;        }         abstract boolean hasName(Object ob, Object name);         Object forName(Object name) {            Object[] oa = (Object[])cache.get();            if (oa == null) {                oa = new Object[size];                cache.set(oa);            } else {                for (int i = 0; i < oa.length; i++) {                    Object ob = oa[i];                    if (ob == null)                        continue;                    if (hasName(ob, name)) {                        if (i > 0)                            moveToFront(oa, i);                        return ob;                    }                }            }             // Create a new object            Object ob = create(name);            oa[oa.length - 1] = ob;            moveToFront(oa, oa.length - 1);            return ob;        }     }     private static Cache decoderCache = new Cache(CACHE_SIZE) {            boolean hasName(Object ob, Object name) {                if (name instanceof String)                    return (((CharsetDecoder)ob).charset().name().equals(name));                if (name instanceof Charset)                    return ((CharsetDecoder)ob).charset().equals(name);                return false;            }            Object create(Object name) {                if (name instanceof String)                    return Charset.forName((String)name).newDecoder();                if (name instanceof Charset)                    return ((Charset)name).newDecoder();                assert false;                return null;            }        };     public static CharsetDecoder decoderFor(Object name) {        CharsetDecoder cd = (CharsetDecoder)decoderCache.forName(name);        cd.reset();        return cd;    }     private static Cache encoderCache = new Cache(CACHE_SIZE) {            boolean hasName(Object ob, Object name) {                if (name instanceof String)                    return (((CharsetEncoder)ob).charset().name().equals(name));                if (name instanceof Charset)                    return ((CharsetEncoder)ob).charset().equals(name);                return false;            }            Object create(Object name) {                if (name instanceof String)                    return Charset.forName((String)name).newEncoder();                if (name instanceof Charset)                    return ((Charset)name).newEncoder();                assert false;                return null;            }        };     public static CharsetEncoder encoderFor(Object name) {        CharsetEncoder ce = (CharsetEncoder)encoderCache.forName(name);        ce.reset();        return ce;    } }