[airq] StringIndexOutOfBoundsException on empty usercalib

[MikeTheTux]

The binding throws a StringIndexOutOfBoundsException. I guess it happens in case of empty "usercalib":{}:

Trace:

...
2022-12-12 14:56:04.660 [DEBUG] [ab.binding.airq.internal.AirqHandler] - air-Q - airqHandler - getConfigData(): decObj={"mqtt":null, ... "usercalib":{}, ...}
...
2022-12-12 14:56:04.687 [TRACE] [ab.binding.airq.internal.AirqHandler] - air-Q - airqHandler - processType(): airqName=usercalib, channelName=userCalib, type=calib
2022-12-12 14:56:04.688 [WARN ] [ab.binding.airq.internal.AirqHandler] - air-Q - airqHandler - getConfigData(): Error in processConfigData(): java.lang.StringIndexOutOfBoundsException: begin 0, end -1, length 0
...

Your Environment

openHAB 3.4.0.M4
My air-Q is actually quiet new. I did not perform any calibration. It is used without beeing connected to the cloud.

[MikeTheTux]

The same issue was already reported here: https://community.openhab.org/t/new-air-q-binding/115989/6

[MikeTheTux]

The following length-check in the java code of the binding fixes the issue:

if (str.length() >= 1) {
    updateState(channelName, new StringType(str.substring(0, str.length() - 1)));
} else {
    logger.trace(
            "air-Q - airqHandler - processType(): Cannot extract calibration data from this string: {}",
            dec.get(airqName).toString());
}

I'm thinking of creating a PR with those changes.

[lolodomo]

Rather str.isEmpty()

[MikeTheTux]

Rather str.isEmpty()

In that case that would be the better choice, but there are other cases that need to check for a min lenght of 2:

if (arrstr.length() >= 2) {
    logger.trace("air-Q - airqHandler - processType(): property array {} set to {}",
            channelName, arrstr.substring(0, arrstr.length() - 2));
    getThing().setProperty(channelName, arrstr.substring(0, arrstr.length() - 2));
} else {
    logger.trace("air-Q - airqHandler - processType(): cannot handle this as an array: {}",
            proparr);
}

[lolodomo]

Closed by merged PR #14000