@Override
  protected void tupleSchemeWriteValue(org.apache.thrift.protocol.TProtocol oprot) throws org.apache.thrift.TException {
    switch (setField_) {
      case NAMES:
        java.util.List<java.lang.String> names = (java.util.List<java.lang.String>)value_;
        {
          oprot.writeListBegin(new org.apache.thrift.protocol.TList(org.apache.thrift.protocol.TType.STRING, names.size()));
          for (java.lang.String _iter696 : names)
          {
            oprot.writeString(_iter696);
          }
          oprot.writeListEnd();
        }
        return;
      case EXPRS:
        java.util.List<DropPartitionsExpr> exprs = (java.util.List<DropPartitionsExpr>)value_;
        {
          oprot.writeListBegin(new org.apache.thrift.protocol.TList(org.apache.thrift.protocol.TType.STRUCT, exprs.size()));
          for (DropPartitionsExpr _iter697 : exprs)
          {
            _iter697.write(oprot);
          }
          oprot.writeListEnd();
        }
        return;
      default:
        throw new java.lang.IllegalStateException("Cannot write union with unknown field " + setField_);
    }
  }
Find the _Fields constant that matches name, or null if its not found.
standalone-metastore/metastore-common/src/gen/thrift/gen-javabean/org/apache/hadoop/hive/metastore/api/RequestPartsSpec.java