uk.ac.starlink.fits

Class StandardFitsTableSerializer

java.lang.Object

uk.ac.starlink.fits.StandardFitsTableSerializer

All Implemented Interfaces:

FitsTableSerializer

Direct Known Subclasses:

VariableFitsTableSerializer

public class StandardFitsTableSerializer
extends Object
implements FitsTableSerializer

Class which knows how to do the various bits of serializing a StarTable to FITS BINTABLE format. A normal (row-oriented) organisation of the data is used. Array-valued columns are all written as fixed size arrays. This class does the hard work for FitsTableWriter.

When writing tables that are marked up using the headers defined in HealpixTableInfo, this serializer will attempt to insert FITS headers corresponding to the HEALPix-FITS convention.

Author:

Mark Taylor (Starlink)

See Also:

HEALPix-FITS convention

Constructor Summary

Constructors

Constructor and Description
StandardFitsTableSerializer(FitsTableSerializerConfig config, StarTable table) Constructor.

Method Summary

Modifier and Type	Method and Description
String	getBadValue(int icol) Returns the bad value (text of the TNULLnn card), if any, used for a given column.
FitsTableSerializerConfig	getConfig() Returns the configuration information for this serializer.
int[]	getDimensions(int icol) Returns the dimensions of the items which will be output for a given column.
char	getFormatChar(int icol) Returns the FITS TFORM letter which describes the type of data output for a given column.
CardImage[]	getHeader() Returns header cards suitable for the HDU which will contain the table.
protected CardImage[]	getHealpixHeaders(HealpixTableInfo hpxInfo) Returns FITS headers specific for a table containing a HEALPix map.
long	getRowCount() Returns the number of rows which will be output.
void	writeData(DataOutput strm) Writes the HDU data for the table to an output stream.
long	writeDataOnly(DataOutput strm) Writes the table data content without any trailing padding.

Methods inherited from class java.lang.Object

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

Constructor Detail

StandardFitsTableSerializer

public StandardFitsTableSerializer(FitsTableSerializerConfig config,
                                   StarTable table)
                            throws IOException

Constructor.

Parameters:

config - configuration

table - table to serialize

Throws:

IOException - if it won't be possible to write the given table

Method Detail

getConfig

public FitsTableSerializerConfig getConfig()

Returns the configuration information for this serializer.

Returns:

config

getHeader

public CardImage[] getHeader()

Description copied from interface: FitsTableSerializer

Returns header cards suitable for the HDU which will contain the table. Additional metadata and an END marker will be added after these cards, so the returned array must not contain the END card.

Specified by:

getHeader in interface FitsTableSerializer

Returns:

header cards

writeData

public void writeData(DataOutput strm)
               throws IOException

Description copied from interface: FitsTableSerializer

Writes the HDU data for the table to an output stream. This is only intended to be called once following creation of this object. Subsequent calls result in undefined behaviour.

Specified by:

writeData in interface FitsTableSerializer

Parameters:

strm - destination stream

Throws:

IOException

writeDataOnly

public long writeDataOnly(DataOutput strm)
                   throws IOException

Writes the table data content without any trailing padding.

Parameters:

strm - destination stream

Returns:

number of bytes written

Throws:

IOException

getFormatChar

public char getFormatChar(int icol)

Description copied from interface: FitsTableSerializer

Returns the FITS TFORM letter which describes the type of data output for a given column. This is as described by the FITS standard - 'J' for 4-byte integer, 'A' for characters, etc. If the column is not being output, (char)0 will be returned.

Specified by:

getFormatChar in interface FitsTableSerializer

Parameters:

icol - column to query

Returns:

format letter for data in column icol, or 0 for a column being skipped

getDimensions

public int[] getDimensions(int icol)

Description copied from interface: FitsTableSerializer

Returns the dimensions of the items which will be output for a given column. This will be null only if that column is not being output. Otherwise it will be a zero-element array for a scalar, 1-element array for a vector, etc.

Specified by:

getDimensions in interface FitsTableSerializer

Parameters:

icol - column to query

Returns:

dimensions array for data in column icol or null for a column being skipped

getBadValue

public String getBadValue(int icol)

Description copied from interface: FitsTableSerializer

Returns the bad value (text of the TNULLnn card), if any, used for a given column.

Specified by:

getBadValue in interface FitsTableSerializer

Parameters:

icol - column to query

Returns:

blank value string, or null if there is none or the column is being skipped

getRowCount

public long getRowCount()

Description copied from interface: FitsTableSerializer

Returns the number of rows which will be output.

Specified by:

getRowCount in interface FitsTableSerializer

Returns:

row count

getHealpixHeaders

protected CardImage[] getHealpixHeaders(HealpixTableInfo hpxInfo)
                                 throws TableFormatException

Returns FITS headers specific for a table containing a HEALPix map. If this method is called the assumption is that the table looks like it should be a HEALPix map of some sort. If there are problems with the metadata that prevent a consistent set of headers from being generated, a TableFormatException with an informative message should be thrown.

Parameters:

hpxInfo - non-null healpix description

Returns:

array of FITS headers describing healpix information

Throws:

TableFormatException