LogEventDecoder.java

package com.manning.nettyinaction.chapter13;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.socket.DatagramPacket;
import io.netty.handler.codec.MessageToMessageDecoder;
import io.netty.util.CharsetUtil;

import java.util.List;

/**
 * @author <a href="mailto:norman.maurer@googlemail.com">Norman Maurer</a>
 */
public class LogEventDecoder extends MessageToMessageDecoder<DatagramPacket> {
    @Override
    protected void decode(ChannelHandlerContext ctx, DatagramPacket datagramPacket, List<Object> out) throws Exception {
        ByteBuf data = datagramPacket.content();
        int i = data.indexOf(0, data.readableBytes(), LogEvent.SEPARATOR);
        String filename = data.slice(0, i).toString(CharsetUtil.UTF_8);
        String logMsg =  data.slice(i + 1, data.readableBytes()).toString(CharsetUtil.UTF_8);

        LogEvent event = new LogEvent(datagramPacket.recipient(), System.currentTimeMillis(),
                filename,logMsg);
        out.add(event);
    }
}