se.sics.kompics.network.netty.MessageDecoder.java Source code

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Here is the source code for se.sics.kompics.network.netty.MessageDecoder.java

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/* 
 * This file is part of the CaracalDB distributed storage system.
 *
 * Copyright (C) 2009 Swedish Institute of Computer Science (SICS) 
 * Copyright (C) 2009 Royal Institute of Technology (KTH)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
package se.sics.kompics.network.netty;

import com.google.common.base.Optional;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import se.sics.kompics.network.netty.serialization.Serializers;

/**
 *
 * @author Lars Kroll <lkroll@kth.se>
 */
public class MessageDecoder extends LengthFieldBasedFrameDecoder {

    public MessageDecoder() {
        super(65532, 0, 2, 0, 2);
    }

    @Override
    protected Object decode(ChannelHandlerContext ctx, ByteBuf in) throws Exception {
        ByteBuf frame = (ByteBuf) super.decode(ctx, in);
        if (frame == null) {
            return null;
        }

        NettyNetwork.LOG.trace("Trying to decode incoming {} bytes of data from {} to {}.", new Object[] {
                frame.readableBytes(), ctx.channel().remoteAddress(), ctx.channel().localAddress() });
        Object o = Serializers.fromBinary(frame, Optional.absent());
        NettyNetwork.LOG.trace("Decoded incoming data from {}: ", ctx.channel().remoteAddress(), o);
        return o;
    }

    @Override
    protected ByteBuf extractFrame(ChannelHandlerContext ctx, ByteBuf buffer, int index, int length) {
        return buffer.slice(index, length);
    }

}