Question

In our Java program we receive an Erlang tuple and extract it in OtpErlangTuple. One of the elements of the tuple should be a string but can be empty. When it is empty, its value is [] – the Erlang way of representing an empty list.

My question is how to check if the element is empty so to cast it to a OtpErlangString?

As it is now (OtpErlangString)messageData.elementAt(2), the following exception is raised:

class java.lang.ClassCastException
, 'com.ericsson.otp.erlang.OtpErlangList cannot be cast to com.ericsson.otp.erla
ng.OtpErlangString'

Thanks,

Martin

Answer 1

Check if it is equal to [] and do a specific operation if so:

OtpErlangString convertedString;
if(messageData.elementAt(2).toString().equals("[]")) {
    // do something assigning some value to convertedString
} else {
    convertedString = (OtpErlangString) messageData.elementAt(2);
}

You can handle this case the way you want depending on how you then manage those OtpErlangString