uk.ac.starlink.votable

Class ColFitsPlusTableWriter

java.lang.Object

uk.ac.starlink.table.StreamStarTableWriter

uk.ac.starlink.fits.AbstractFitsTableWriter

uk.ac.starlink.votable.VOTableFitsTableWriter

uk.ac.starlink.votable.ColFitsPlusTableWriter

All Implemented Interfaces:

MultiStarTableWriter, StarTableWriter

public class ColFitsPlusTableWriter
extends VOTableFitsTableWriter

Handles writing of a StarTable in a column-oriented FITS binary table format. The table data is stored in a BINTABLE extension which has a single row; each cell in this row contains the data for an entire column of the represented table. The primary HDU is a byte array containing a VOTable representation of the table metadata, as for FitsPlusTableWriter.

This rather specialised format may provide good performance for certain operations on very large, especially very wide, tables. Although it is FITS and can therefore be used in principle for data interchange, in practice most non-STIL processors are unlikely to be able to do much useful with it.

Since:

21 Jun 2006

Constructor Summary

Constructors

Constructor and Description
ColFitsPlusTableWriter() Default constructor.
ColFitsPlusTableWriter(java.lang.String name, uk.ac.starlink.fits.WideFits wide) Custom constructor.

Method Summary

Modifier and Type	Method and Description
protected uk.ac.starlink.fits.FitsTableSerializer	createSerializer(StarTable table) Provides a suitable serializer for a given table.
protected void	customisePrimaryHeader(nom.tam.fits.Header hdr) Hook for adding custom entries to the FITS header which is written to the primary HDU.
protected boolean	isMagic(int icard, java.lang.String key, java.lang.String value) Tests a header card to see if it looks like part of the magic number for the format written by this handler.
boolean	looksLikeFile(java.lang.String location) Indicates whether the destination is of a familiar form for this kind of writer.

Methods inherited from class uk.ac.starlink.votable.VOTableFitsTableWriter

isMagic, setVotableVersion, writeStarTables

Methods inherited from class uk.ac.starlink.fits.AbstractFitsTableWriter

addMetadata, getCurrentDate, getFormatName, getMimeType, setFormatName, writePrimaryHDU, writeStarTable, writeStarTables, writeTableHDU

Methods inherited from class uk.ac.starlink.table.StreamStarTableWriter

writeStarTable

Methods inherited from class java.lang.Object

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

Methods inherited from interface uk.ac.starlink.table.StarTableWriter

writeStarTable

Constructor Detail

ColFitsPlusTableWriter

public ColFitsPlusTableWriter()

Default constructor.

ColFitsPlusTableWriter

public ColFitsPlusTableWriter(java.lang.String name,
                              uk.ac.starlink.fits.WideFits wide)

Custom constructor.

Parameters:

name - writer name

wide - convention for representing over-wide tables; null to avoid this convention

Method Detail

looksLikeFile

public boolean looksLikeFile(java.lang.String location)

Description copied from interface: StarTableWriter

Indicates whether the destination is of a familiar form for this kind of writer. This may be used to guess what kind of format a table should be written in. Implementations should return true for values of location which look like the normal form for their output format, for instance one with the usual file extension.

Parameters:

location - the location name (probably filename)

Returns:

true iff it looks like a file this writer would normally write

customisePrimaryHeader

protected void customisePrimaryHeader(nom.tam.fits.Header hdr)
                               throws nom.tam.fits.HeaderCardException

Description copied from class: VOTableFitsTableWriter

Hook for adding custom entries to the FITS header which is written to the primary HDU. This is called just after the required cards (SIMPLE, BITPIX, NAXIS, NAXIS1 ) are added and just before the EXTEND card.

Specified by:

customisePrimaryHeader in class VOTableFitsTableWriter

Parameters:

hdr - header

Throws:

nom.tam.fits.HeaderCardException

isMagic

protected boolean isMagic(int icard,
                          java.lang.String key,
                          java.lang.String value)

Description copied from class: VOTableFitsTableWriter

Tests a header card to see if it looks like part of the magic number for the format written by this handler. The VOTableFitsTableWriter implementation tests that the first four cards read:

    SIMPLE = T
    BITPIX = 8
    NAXIS  = 1
    NAXIS1 = ???
 

Subclasses may override this to add tests for later cards (as written in VOTableFitsTableWriter.customisePrimaryHeader(nom.tam.fits.Header)).

Overrides:

isMagic in class VOTableFitsTableWriter

Parameters:

icard - 0-based card index

key - card name

value - card value

Returns:

true iff the presented card is one that could have been written by this writer

createSerializer

protected uk.ac.starlink.fits.FitsTableSerializer createSerializer(StarTable table)
                                                            throws java.io.IOException

Description copied from class: uk.ac.starlink.fits.AbstractFitsTableWriter

Provides a suitable serializer for a given table. Note this should throw an IOException if it can be determined that the submitted table cannot be written by this writer, for instance if it has too many columns.

Specified by:

createSerializer in class uk.ac.starlink.fits.AbstractFitsTableWriter

Parameters:

table - table to serialize

Returns:

FITS serializer

Throws:

java.io.IOException - if the table can't be written