XMLGregorianCalendar type blocks this lib in spark projects

[Michał Siatkowski]

steps

define schema A that has type="dt:date" element
compile them.

problem

No Encoder found for javax.xml.datatype.XMLGregorianCalendar

expectation

Spark Encoders are actually a bit of pain in the ***, because there is not a lot of them right now:
https://spark.apache.org/docs/2.1.0/api/java/org/apache/spark/sql/Encoders.html

So even the types prosed in #376
will not solve the issue, because there is only an Encoder for java.sql.Date and java.sql.Timestamp

I know it sounds medieval but we basically used String for that fields 😢

So I guess, the most flexible and easy solution would be to have a field:
dateTypeClass where user could provide a full path to the desired class. Let it be current Calendar, Date or String.

WDYT?

[eugene yokota]

Could you comment on #376 please?