ru.yandex.clickhouse.jdbcbridge.core

Interface DataTableReader

public interface DataTableReader

Interface for reading tabular data and writing to response.

Since:

2.0

Method Summary

Modifier and Type	Method and Description
boolean	isNull(int row, int column, ColumnDefinition metadata) Check whether a cell is null or not.
boolean	nextRow() Move cursor to next row.
default void	process(String dataSourceId, ColumnDefinition[] requestColumns, ColumnDefinition[] customColumns, ColumnDefinition[] resultColumns, DefaultValues defaultValues, TimeZone timezone, QueryParameters params, ResponseWriter writer) Stream tabular data to response.
void	read(int row, int column, ColumnDefinition metadata, ByteBuffer buffer) Read value from a cell and write into given ByteBuffer.
default int	skipRows(QueryParameters parameters)

Method Detail

nextRow

boolean nextRow()
         throws DataAccessException

Move cursor to next row. This should be called at least once before read anything.

Returns:

true if there's more rows to read; false otherwise

Throws:

DataAccessException

isNull

boolean isNull(int row,
               int column,
               ColumnDefinition metadata)
        throws DataAccessException

Check whether a cell is null or not.

Parameters:

row - zero-based row index

column - zero-based column index

metadata - column metadata

Returns:

true if the cell is null; false otherwise

Throws:

DataAccessException

read

void read(int row,
          int column,
          ColumnDefinition metadata,
          ByteBuffer buffer)
   throws DataAccessException

Read value from a cell and write into given ByteBuffer.

Parameters:

row - zero-based row index

column - zero-based column index

metadata - column metadata

buffer - byte buffer

Throws:

DataAccessException

process

default void process(String dataSourceId,
                     ColumnDefinition[] requestColumns,
                     ColumnDefinition[] customColumns,
                     ColumnDefinition[] resultColumns,
                     DefaultValues defaultValues,
                     TimeZone timezone,
                     QueryParameters params,
                     ResponseWriter writer)
              throws DataAccessException

Stream tabular data to response.

Parameters:

dataSourceId - id of the datasource

requestColumns - requested columns

customColumns - custom columns defined in datasource

resultColumns - result columns

defaultValues - default values defined in datasource

timezone - preferred timezone

params - query parameters

writer - response writer

Throws:

DataAccessException

skipRows

default int skipRows(QueryParameters parameters)