Throw Exception when retrieving non-existing Field in Response

[Julian Feinauer]

Hi all,

I found some time today to test and toy around a bit with PLC4X and I 
discovered a behavior which I found weird.
I had the response from a request which “failed” (Response was successful but 
the Field I wanted was NOT_FOUND).
So my response.getLong(“…”) returned a “null” and a subsequent implicit cast to 
long finally led to a NPE.

My expected behavior would be an Exception (Runtime Exception).
Also in the case when I try to fetch a filed which is non-existent.
Currently we return null in both cases (see snippet from 
DefaultPlcReadResponse):

private BaseDefaultFieldItem getFieldInternal(String name) {
    // If this field doesn't exist, ignore it.
    if (values.get(name) == null) {
        return null;
    }
    if (values.get(name).getKey() != PlcResponseCode.OK) {
        return null;
   }
    return values.get(name).getValue();
}

I suggest to throw a Runtime Exception in both cases to give a “valid” Error 
Message instead of a NPE which is totally unexpected.

Is this okay for everybody? Or are there any concerns?

Julian