private static PB.FilterType EncodeFilterType(ColumnConditionType type)
        {
            switch (type)
            {
            case ColumnConditionType.COMPOSITE_CONDITION:
                return(PB.FilterType.FT_COMPOSITE_COLUMN_VALUE);

            case ColumnConditionType.RELATIONAL_CONDITION:
                return(PB.FilterType.FT_SINGLE_COLUMN_VALUE);

            default:
                throw new ArgumentException("Unknown filter type: " + type);
            }
        }
        private PB.ColumnConditionType MakeColumnConditionType(ColumnConditionType type)
        {
            switch (type)
            {
            case ColumnConditionType.COMPOSITE_CONDITION:
                return(PB.ColumnConditionType.CCT_COMPOSITE);

            case ColumnConditionType.RELATIONAL_CONDITION:
                return(PB.ColumnConditionType.CCT_RELATION);

            default:
                throw new OTSClientException(String.Format("Invalid column condition type: {0}", type));
            }
        }