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/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
package org.apache.qpid.amqp_1_0.codec;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import java.util.LinkedHashMap;
import java.util.Map;
public class StringWriter extends SimpleVariableWidthWriter<String>
{
private static final Charset ENCODING_CHARSET;
private static final byte ONE_BYTE_CODE;
private static final byte FOUR_BYTE_CODE;
static
{
Charset defaultCharset = Charset.defaultCharset();
if(defaultCharset.name().equals("UTF-16") || defaultCharset.name().equals("UTF-16BE"))
{
ENCODING_CHARSET = defaultCharset;
ONE_BYTE_CODE = (byte) 0xa2;
FOUR_BYTE_CODE = (byte) 0xb2;
}
else
{
ENCODING_CHARSET = Charset.forName("UTF-8");
ONE_BYTE_CODE = (byte) 0xa1;
FOUR_BYTE_CODE = (byte) 0xb1;
}
}
private static final class ValueCache<K,V> extends LinkedHashMap<K,V>
{
private final int _cacheSize;
public ValueCache(int cacheSize)
{
_cacheSize = cacheSize;
}
@Override
protected boolean removeEldestEntry(Map.Entry<K, V> eldest)
{
return size() > _cacheSize;
}
public boolean isFull()
{
return size() == _cacheSize;
}
}
private final ValueCache<String, byte[]> _cachedEncodings = new ValueCache<String, byte[]>(10);
@Override
protected byte getFourOctetEncodingCode()
{
return FOUR_BYTE_CODE;
}
@Override
protected byte getSingleOctetEncodingCode()
{
return ONE_BYTE_CODE;
}
@Override
protected byte[] getByteArray(String value)
{
byte[] encoding;
boolean isFull = _cachedEncodings.isFull();
if(isFull)
{
encoding = _cachedEncodings.remove(value);
}
else
{
encoding = _cachedEncodings.get(value);
}
if(encoding == null)
{
ByteBuffer buf = ENCODING_CHARSET.encode(value);
if(buf.hasArray() && buf.arrayOffset() == 0 && buf.limit()==buf.capacity())
{
encoding = buf.array();
}
else
{
byte[] bufArray = new byte[buf.limit()-buf.position()];
buf.get(bufArray);
encoding = bufArray;
}
_cachedEncodings.put(value,encoding);
}
else if(isFull)
{
_cachedEncodings.put(value,encoding);
}
return encoding;
}
@Override
protected int getOffset()
{
return 0;
}
private static Factory<String> FACTORY = new Factory<String>()
{
public ValueWriter<String> newInstance(Registry registry)
{
return new StringWriter();
}
};
public static void register(ValueWriter.Registry registry)
{
registry.register(String.class, FACTORY);
}
}
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