public List<HivePrivilegeObject> applyRowFilterAndColumnMasking(List<HivePrivilegeObject> privObjs)
      throws SemanticException {
    return authorizer.applyRowFilterAndColumnMasking(queryContext, privObjs);
  }
The main purpose for this class is for authorization. More specifically, row
filtering and column masking are done through this class. We first call
create function to create the corresponding strings for row filtering and
column masking. We then replace the TAB_REF with the strings.
ql/src/java/org/apache/hadoop/hive/ql/parse/TableMask.java