public HiveVarcharConverter(PrimitiveObjectInspector inputOI,
SettableHiveVarcharObjectInspector outputOI) {
this.inputOI = inputOI;
this.outputOI = outputOI;
VarcharTypeParams typeParams = (VarcharTypeParams) outputOI.getTypeParams();
// unfortunately we seem to get instances of varchar object inspectors without params
// when an old-style UDF has an evaluate() method with varchar arguments.
// If we disallow varchar in old-style UDFs and only allow GenericUDFs to be defined
// with varchar arguments, then we might be able to enforce this properly.