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/*
* Copyright (c) 2001, 2011, 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.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<Object[]> 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 = 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;
}
}
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