/*
* Copyright 2013 - 2014 Anton Tananaev (anton@traccar.org)
*
* 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 org.traccar.protocol;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.handler.codec.frame.LengthFieldBasedFrameDecoder;
public class AtrackFrameDecoder extends LengthFieldBasedFrameDecoder {
private static final int KEEPALIVE_LENGTH = 12;
public AtrackFrameDecoder() {
super(1024, 4, 2);
}
@Override
protected Object decode(
ChannelHandlerContext ctx, Channel channel, ChannelBuffer buf) throws Exception {
// Keep alive message
if (buf.readableBytes() >= KEEPALIVE_LENGTH
&& buf.getUnsignedShort(buf.readerIndex()) == 0xfe02) {
return buf.readBytes(KEEPALIVE_LENGTH);
}
return super.decode(ctx, channel, buf);
}
}