uk.ac.starlink.ttools.filter

Class PermutedColumnSupplement

java.lang.Object

uk.ac.starlink.ttools.filter.PermutedColumnSupplement

All Implemented Interfaces:

ColumnSupplement

public class PermutedColumnSupplement
extends Object
implements ColumnSupplement

ColumnSupplement implementation which contains a selection of the columns in the base table. Each column is a view of one in the base table.

An int[] array, colMap, is used to keep track of which columns in this table correspond to which columns in the base table; the i'th column in this table corresponds to the colMap[i]'th column in the base table. The colMap array may contain duplicate entries, but all its entries must be in the range 0..baseSup.getColumnCount()-1. This table will have colMap.length columns.

Since:

2 Apr 2012

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
PermutedColumnSupplement(ColumnSupplement baseSup, int[] colMap) Constructs a permuted column supplement based on a given column supplement.
PermutedColumnSupplement(StarTable baseTable, int[] colMap) Constructs a permuted column supplement based on a given table.

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.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PermutedColumnSupplement

public PermutedColumnSupplement(ColumnSupplement baseSup,
                                int[] colMap)

Constructs a permuted column supplement based on a given column supplement.

Parameters:

baseSup - column supplement supplying the base data

colMap - array of column indices, one for each column in this object

PermutedColumnSupplement

public PermutedColumnSupplement(StarTable baseTable,
                                int[] colMap)

Constructs a permuted column supplement based on a given table.

Parameters:

baseTable - table supplying the base data

colMap - array of column indices, one for each column in this object

Method Detail

getColumnCount

public int getColumnCount()

Description copied from interface: ColumnSupplement

Returns the number of columns defined by this object.

Specified by:

getColumnCount in interface ColumnSupplement

Returns:

number of columns

getColumnInfo

public ColumnInfo getColumnInfo(int icol)

Description copied from interface: ColumnSupplement

Returns the column metadata object for a given column.

Specified by:

getColumnInfo in interface ColumnSupplement

Parameters:

icol - column index within this object

Returns:

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

getCell

public Object getCell(long irow,
                      int icol)
               throws IOException

Description copied from interface: ColumnSupplement

Random access read of a cell defined by this object.

Specified by:

getCell in interface ColumnSupplement

Parameters:

irow - row index

icol - column index

Returns:

cell content

Throws:

IOException

getRow

public Object[] getRow(long irow)
                throws IOException

Description copied from interface: ColumnSupplement

Random access read of a row defined by this object.

Specified by:

getRow in interface ColumnSupplement

Parameters:

irow - row index

Returns:

array of cell contents for all the cells in this row

Throws:

IOException

createSupplementData

public SupplementData createSupplementData(RowData rdata)
                                    throws IOException

Description copied from interface: ColumnSupplement

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.

Specified by:

createSupplementData in interface ColumnSupplement

Parameters:

rdata - row accessor providing data from the host table

Returns:

accessor over row data from supplementary columns

Throws:

IOException