/**
* Copyright (C) 2010-2013 Alibaba Group Holding Limited
*
* Licensed 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 com.alibaba.rocketmq.remoting.netty;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import java.nio.ByteBuffer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.alibaba.rocketmq.remoting.common.RemotingHelper;
import com.alibaba.rocketmq.remoting.common.RemotingUtil;
import com.alibaba.rocketmq.remoting.protocol.RemotingCommand;
/**
* 协议解码器
*
* @author shijia.wxr<vintage.wang@gmail.com>
* @since 2013-7-13
*/
public class NettyDecoder extends LengthFieldBasedFrameDecoder {
private static final Logger log = LoggerFactory.getLogger(RemotingHelper.RemotingLogName);
private static final int FRAME_MAX_LENGTH = //
Integer.parseInt(System.getProperty("com.rocketmq.remoting.frameMaxLength", "8388608"));
public NettyDecoder() {
super(FRAME_MAX_LENGTH, 0, 4, 0, 4);
}
@Override
public Object decode(ChannelHandlerContext ctx, ByteBuf in) throws Exception {
ByteBuf frame = null;
try {
frame = (ByteBuf) super.decode(ctx, in);
if (null == frame) {
return null;
}
ByteBuffer byteBuffer = frame.nioBuffer();
return RemotingCommand.decode(byteBuffer);
}
catch (Exception e) {
log.error("decode exception, " + RemotingHelper.parseChannelRemoteAddr(ctx.channel()), e);
// 这里关闭后， 会在pipeline中产生事件，通过具体的close事件来清理数据结构
RemotingUtil.closeChannel(ctx.channel());
}
finally {
if (null != frame) {
frame.release();
}
}
return null;
}
}