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package com.feingto.iot.common.handler;

import com.feingto.iot.common.Constants;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.handler.codec.mqtt.MqttMessage;
import lombok.extern.slf4j.Slf4j;

/**
 * 通道Inbound处理器抽象
 *
 * @author longfei
 */
@Slf4j
public abstract class DefaultChannelInboundHandler extends ChannelInboundHandlerAdapter {
    public abstract void handleMessage(ChannelHandlerContext ctx, Object msg);

    /**
     * 当一个Channel注册到EventLoop上，可以处理I/O时被调用
     */
    @Override
    public void channelRegistered(ChannelHandlerContext ctx) {
        log.info("{} registered, current connected: {}", ctx.channel().remoteAddress(),
                Constants.CONNECT_COUNTER.incrementAndGet());
    }

    /**
     * 当一个Channel从它的EventLoop上解除注册，不再处理I/O时被调用
     */
    @Override
    public void channelUnregistered(ChannelHandlerContext ctx) {
        log.info("{} unregistered, current connected: {}", ctx.channel().remoteAddress(),
                Constants.CONNECT_COUNTER.decrementAndGet());
    }

    /**
     * 当从Channel中读数据时被调用
     */
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) {
        if (msg instanceof MqttMessage) {
            ctx.fireChannelRead(msg);
        } else {
            handleMessage(ctx, msg);
        }
    }

    /**
     * 当Channel上的某个读操作完成时被调用
     */
    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) {
        ctx.flush();
    }

    /**
     * 处理过程中ChannelPipeline中发生错误时被调用
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        super.exceptionCaught(ctx, cause);
        cause.printStackTrace();
    }
}