2.1

Two changes.

1.) Change so that initialization in base class BaseFlow does not get overriden in subclasses HadoopFlow and LocalFlow. See HadoopFlow.preserveTemporaryFiles in particular.

2.) Throw exception if type of Comaparable in Fields is other than Integer or String. Not sure about this one, but, after all, you are trying to cast to Integer below, which will cause a ClassCastException if Comparable is like a float. Nit.