/*
* 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.mina.filter.codec.netty;
import java.nio.ByteBuffer;
import net.gleamynode.netty2.Message;
import net.gleamynode.netty2.MessageParseException;
import net.gleamynode.netty2.MessageRecognizer;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.core.session.IoSession;
import org.apache.mina.filter.codec.ProtocolDecoder;
import org.apache.mina.filter.codec.ProtocolDecoderAdapter;
import org.apache.mina.filter.codec.ProtocolDecoderException;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
/**
* A MINA {@link ProtocolDecoder} that decodes buffers into
* Netty2 {@link Message}s using specified {@link MessageRecognizer}s.
*
* @author The Apache MINA Project (dev@mina.apache.org)
* @version $Rev: 671827 $, $Date: 2008-06-26 10:49:48 +0200 (Thu, 26 Jun 2008) $,
*/
public class NettyDecoder extends ProtocolDecoderAdapter {
private final MessageRecognizer recognizer;
private ByteBuffer readBuf = ByteBuffer.allocate(1024);
private Message readingMessage;
/**
* Creates a new instance with the specified {@link MessageRecognizer}.
*/
public NettyDecoder(MessageRecognizer recognizer) {
if (recognizer == null) {
throw new NullPointerException();
}
this.recognizer = recognizer;
}
private void put(IoBuffer in) {
// copy to read buffer
if (in.remaining() > readBuf.remaining()) {
expand((readBuf.position() + in.remaining()) * 3 / 2);
}
readBuf.put(in.buf());
}
private void expand(int newCapacity) {
ByteBuffer newBuf = ByteBuffer.allocate(newCapacity);
readBuf.flip();
newBuf.put(readBuf);
readBuf = newBuf;
}
public void decode(IoSession session, IoBuffer in,
ProtocolDecoderOutput out) throws Exception {
put(in);
Message m = readingMessage;
try {
for (;;) {
readBuf.flip();
if (m == null) {
int limit = readBuf.limit();
boolean failed = true;
try {
m = recognizer.recognize(readBuf);
failed = false;
} finally {
if (failed) {
// clear the read buffer if failed to recognize
readBuf.clear();
break;
} else {
if (m == null) {
readBuf.limit(readBuf.capacity());
readBuf.position(limit);
break; // finish decoding
} else {
// reset buffer for read
readBuf.limit(limit);
readBuf.position(0);
}
}
}
}
if (m != null) {
try {
if (m.read(readBuf)) {
out.write(m);
m = null;
} else {
break;
}
} finally {
if (readBuf.hasRemaining()) {
readBuf.compact();
} else {
readBuf.clear();
break;
}
}
}
}
} catch (MessageParseException e) {
m = null; // discard reading message
throw new ProtocolDecoderException("Failed to decode.", e);
} finally {
readingMessage = m;
}
}
}