MessageBase

package com.camellias.voidaicarcania.network;

import net.minecraft.entity.player.EntityPlayer;
import net.minecraftforge.fml.common.network.simpleimpl.IMessage;
import net.minecraftforge.fml.common.network.simpleimpl.IMessageHandler;
import net.minecraftforge.fml.common.network.simpleimpl.MessageContext;
import net.minecraftforge.fml.relauncher.Side;

public abstract class MessageBase<REQ extends IMessage> implements IMessage, IMessageHandler<REQ, REQ>
{
    @Override
    public REQ onMessage(REQ message, MessageContext ctx)
    {
        if(ctx.side == Side.SERVER)
        {
            handleServerSide(message, ctx.getServerHandler().player);
        }
        else
        {
            handleClientSide(message, null);
        }
        return null;
    }

    public abstract void handleClientSide(REQ message, EntityPlayer player);

    public abstract void handleServerSide(REQ message, EntityPlayer player);
}