uk.ac.starlink.ttools.filter

Interface ColumnSupplement

All Known Implementing Classes:

CalculatorColumnSupplement, JELColumnSupplement, PermutedColumnSupplement, UnitColumnSupplement

public interface ColumnSupplement

Defines additional column metadata and data for supplementing the existing columns in a StarTable. The data will typically be acquired by reference to a host table, for instance calculating cell values in the additional columns on the basis of values for columns in the host table. The columns are assumed to have the same row count as the host table.

Since:

2 Apr 2012

Author:

Mark Taylor

Method Summary

Modifier and Type	Method and Description
SupplementData	createSupplementData(RowData rdata) Returns a new accessor for the values in the columns defined by this object.
Object	getCell(long irow, int icol) Random access read of a cell defined by this object.
int	getColumnCount() Returns the number of columns defined by this object.
ColumnInfo	getColumnInfo(int icol) Returns the column metadata object for a given column.
Object[]	getRow(long irow) Random access read of a row defined by this object.

Method Detail

getColumnCount

int getColumnCount()

Returns the number of columns defined by this object.

Returns:

number of columns

getColumnInfo

ColumnInfo getColumnInfo(int icol)

Returns the column metadata object for a given column.

Parameters:

icol - column index within this object

Returns:

column metadata for the icol'th column defined by this object

getCell

Object getCell(long irow,
               int icol)
        throws IOException

Random access read of a cell defined by this object.

Parameters:

irow - row index

icol - column index

Returns:

cell content

Throws:

IOException

getRow

Object[] getRow(long irow)
         throws IOException

Random access read of a row defined by this object.

Parameters:

irow - row index

Returns:

array of cell contents for all the cells in this row

Throws:

IOException

createSupplementData

SupplementData createSupplementData(RowData rdata)
                             throws IOException

Returns a new accessor for the values in the columns defined by this object. The supplied row object must be from an appropriate host table; if not, behaviour is undefined.

Parameters:

rdata - row accessor providing data from the host table

Returns:

accessor over row data from supplementary columns

Throws:

IOException