@Override
    public int hashCode() {
      final int prime = 31;
      int result = 1;
      result = prime * result + ((dc == null) ? 0 : dc.hashCode());
      result = prime * result + ((fld == null) ? 0 : fld.hashCode());
      return result;
    }
Constructor.

@param dc The associated data container.
@param fld The associated field schema.
ql/src/java/org/apache/hadoop/hive/ql/hooks/LineageInfo.java