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From Julian Feinauer <>
Subject Re: Reconnect of driver 2
Date Tue, 26 Mar 2019 11:03:00 GMT
Hi Gunther,

good catch : )
In fact, the isConnected() implementation is currently not soo god.
In fact it checks if the underlying communication channel from netty is connected (which does
not know that it is disconnected yet, in your case).
We already had discussions to introduce a real "request" based implementation like "ping()"
which sends a request.

Furthermore, for your use case there is the PooledDriverManager which does implicitly what
you do... throws away a not working connection and issues a new one, if needed, but that’s
a separate topic.

I think we should spend some effort into this "ping" functionality.
Perhaps you can even assist with the implementation Gunther, what do you think?


Am 26.03.19, 11:19 schrieb "Gunther Gruber" <>:

    Put it another way, isConnected does not work as i expect it
    plcConnection.isConnected() returns true even when i disconnect the vpn (maybe of some
tcp/ip keepalive?)
    this is the snippet of code which i expect to work (instead of the thread which reconnects
ever 10 minutes)
    while (doCollect) {
      try {
        if (plcConnection == null || plcConnection.isConnected() == false) {
          plcConnection = initPLC(config.get(CONNECTION_KEY));
      } catch (PlcConnectionException e) {
        logger.log(Level.WARNING, "error connecting with driver", e);
        plcConnection = null;
      // Create a new read request:
      // - Give the single item requested the alias name "value"
      PlcReadRequest.Builder builder = plcConnection.readRequestBuilder();
    Gunther Gruber

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