Package nom.tam.fits

Class NullData

java.lang.Object

nom.tam.fits.Data

nom.tam.fits.ImageData

nom.tam.fits.NullData

All Implemented Interfaces:

FitsElement

public final class NullData
extends ImageData

A subclass of Data containing no actual data. It wraps an underlying data of null.

Since:

1.18

Author:

Attila Kovacs

See Also:

• NullDataHDU

Constructor Summary

Constructors

Constructor	Description
NullData()

Method Summary

Modifier and Type	Method	Description
void	read(ArrayDataInput in)	Reads the data or skips over it for reading later, depending on whether reading from a stream or a random acessible input, respectively.
void	setBuffer(Buffer data)	Sets the buffer that may hold a serialized version of the data for this image.
void	write(ArrayDataOutput o)	Writes the contents of the element to a data sink, adding padding as necessary if the element (such as a header or data segment) is expected to complete the FITS block of 2880 bytes.

Methods inherited from class nom.tam.fits.ImageData

convertTo, from, getDimensions, getQuantizer, getTiler, getType, isComplexValued, overrideHeaderAxes, setQuantizer, toHDU

Methods inherited from class nom.tam.fits.Data

calcChecksum, detach, getData, getFileOffset, getKernel, getSize, isDeferred, isEmpty, reset, rewrite, rewriteable

Methods inherited from class java.lang.Object

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

Constructor Details

NullData

public NullData()

Method Details

read

public void read(ArrayDataInput in)

Description copied from class: Data

Reads the data or skips over it for reading later, depending on whether reading from a stream or a random acessible input, respectively.

In case the argument is a an instance of RandomAccess input (such as a FitsFile, the call will simply note where in the file the data segment can be found for reading at a later point, only when the data content is accessed. This 'deferred' reading behavior make it possible to process large HDUs even with small amount of RAM, and can result in a significant performance boost when inspectring large FITS files, or using only select content from large FITS files.

Specified by:

read in interface FitsElement

Overrides:

read in class ImageData

Parameters:

in - The input data stream

See Also:

• Data.getData()
• Data.ensureData()

write

public void write(ArrayDataOutput o)

Description copied from interface: FitsElement

Writes the contents of the element to a data sink, adding padding as necessary if the element (such as a header or data segment) is expected to complete the FITS block of 2880 bytes.

Specified by:

write in interface FitsElement

Overrides:

write in class ImageData

Parameters:

o - The data sink.

setBuffer

public void setBuffer(Buffer data)

Description copied from class: ImageData

Sets the buffer that may hold a serialized version of the data for this image.

Overrides:

setBuffer in class ImageData

Parameters:

data - the buffer that may hold this image's data in serialized form.