class HeartBeatTask implements Runnable {

    @Override
    public void run() {
        try {
            long now = System.currentTimeMillis();
            for (Channel channel : channelProvider.getChannels()) {
                if (channel.isClosed()) {
                    continue;
                }
                try {
                    Long lastRead = (Long) channel.getAttribute(
                            HeaderExchangeHandler.KEY_READ_TIMESTAMP);
                    Long lastWrite = (Long) channel.getAttribute(
                            HeaderExchangeHandler.KEY_WRITE_TIMESTAMP);
                    if ((lastRead != null && now - lastRead > heartbeat)
                            || (lastWrite != null && now - lastWrite > heartbeat)) {
                        Request req = new Request();
                        req.setVersion(Version.getProtocolVersion());
                        req.setTwoWay(true);
                        req.setEvent(Request.HEARTBEAT_EVENT);
                        channel.send(req);
                        if (logger.isDebugEnabled()) {
                            logger.debug("Send heartbeat to remote channel " + channel.getRemoteAddress()
                                    + ", cause: The channel has no data-transmission exceeds a heartbeat period: " + heartbeat + "ms");
                        }
                    }
                    if (lastRead != null && now - lastRead > heartbeatTimeout) {
                        logger.warn("Close channel " + channel
                                + ", because heartbeat read idle time out: " + heartbeatTimeout + "ms");
                        if (channel instanceof Client) {
                            try {
                                ((Client) channel).reconnect();
                            } catch (Exception e) {
                                //do nothing
                            }
                        } else {
                            channel.close();
                        }
                    }
                } catch (Throwable t) {
                    logger.warn("Exception when heartbeat to remote channel " + channel.getRemoteAddress(), t);
                }
            }
        } catch (Throwable t) {
            logger.warn("Unhandled exception when heartbeat, cause: " + t.getMessage(), t);
        }
    }

      HeartBeatTask(ChannelProvider provider, int heartbeat, int heartbeatTimeout);

}