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.

Constructor Summary

StandardFitsTableSerializer(StarTable table)
Constructs a serializer which will be able to write a given StarTable.

StandardFitsTableSerializer(StarTable table, boolean allowSignedByte)
Constructs a serializer to write a given StarTable, with explicit instruction about how to write byte-type columns data.

Method Summary

String	getBadValue(int icol) Returns the bad value (text of the TNULLnn card), if any, used for a given column.
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.
nom.tam.fits.Header	getHeader() Returns a header suitable for the HDU which will contain the table.
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.

Methods inherited from class java.lang.Object

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

Constructor Detail

StandardFitsTableSerializer

public StandardFitsTableSerializer(StarTable table,
                                   boolean allowSignedByte)
                            throws IOException

Constructs a serializer to write a given StarTable, with explicit instruction about how to write byte-type columns data. Since FITS bytes are unsigned (unlike, for instance, java bytes), they can cause trouble in some circumstances, so avoiding writing them may sometimes help.

Parameters:

table - the table to be written

allowSignedByte - if true, bytes written as FITS signed bytes (TZERO=-128), if false bytes written as signed shorts

Throws:

IOException

StandardFitsTableSerializer

public StandardFitsTableSerializer(StarTable table)
                            throws IOException

Constructs a serializer which will be able to write a given StarTable. Byte-type columns are written using some default policy.

Parameters:

table - the table to be written

Throws:

IOException

Method Detail

getHeader

public nom.tam.fits.Header getHeader()
                              throws nom.tam.fits.HeaderCardException

Description copied from interface: FitsTableSerializer

Returns a header suitable for the HDU which will contain the table.

Specified by:

getHeader in interface FitsTableSerializer

Returns:

header object

Throws:

nom.tam.fits.HeaderCardException

writeData

public void writeData(DataOutput strm)
               throws IOException

Description copied from interface: FitsTableSerializer

Writes the HDU data for the table to an output stream.

Specified by:

writeData in interface FitsTableSerializer

Parameters:

strm - destination stream

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