uk.ac.starlink.fits

Class FitsHeader

java.lang.Object

uk.ac.starlink.fits.FitsHeader

public class FitsHeader
extends java.lang.Object

Represents the header part of a FITS HDU that has been read. It is composed of a number of ParsedCards.

The FITS 4.0 long-string syntax is supported.

Since:

4 Mar 2022

Field Summary

Fields

Modifier and Type	Field and Description
java.lang.String[]	BORING_KEYS Keywords which are never used as table parameters.

Constructor Summary

Constructors

Constructor and Description
FitsHeader(ParsedCard<?>[] cards) Constructor.

Method Summary

Modifier and Type	Method and Description
java.lang.Boolean	getBooleanValue(java.lang.String key) Returns the boolean value for a card with a given key, if one exists.
ParsedCard<?>[]	getCards() Returns the header cards of which this header is composed.
long	getDataBlockCount() Returns the number of FITS blocks occupied by the Data part of the HDU described by this header.
long	getDataByteCount() Returns the number of bytes occupied by the Data part of the HDU described by this header, rounded up to an integer number of blocks.
DescribedValue	getDescribedValue(java.lang.String key) Returns the content of a card with a given key as a DescribedValue, if such a key exists.
java.lang.Double	getDoubleValue(java.lang.String key) Returns the double value for a card with a given key, if one exists.
long	getHeaderBlockCount() Returns the number of FITS blocks occupied by this header.
long	getHeaderByteCount() Returns the number of bytes occupied by this header, rounded up to an integer number of blocks.
java.lang.Integer	getIntValue(java.lang.String key) Returns the integer value for a card with a given key, if one exists.
java.lang.Long	getLongValue(java.lang.String key) Returns the long value for a card with a given key, if one exists.
java.lang.Number	getNumberValue(java.lang.String key) Returns a numeric value for a card with a given key, if one exists.
int	getRequiredIntValue(java.lang.String key) Returns an integer value for a card with a given key, or throws an exception if none exists.
long	getRequiredLongValue(java.lang.String key) Returns a long value for a card with a given key, or throws an exception if none exists.
java.lang.String	getRequiredStringValue(java.lang.String key) Returns a long value for a card with a given key, or throws an exception if none exists.
java.lang.String	getStringValue(java.lang.String key) Returns the string value for a card with a given key, if one exists.
DescribedValue[]	getUnusedParams() Returns an array of DescribedValue objects suitable for use as items of per-table metadata derived from this FITS header.
java.lang.Object	getValue(java.lang.String key) Returns the untyped value for a card with a given key, if one exists.
void	useKey(java.lang.String key) Marks a given keyword as used.

Methods inherited from class java.lang.Object

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

Field Detail

BORING_KEYS

public final java.lang.String[] BORING_KEYS

Keywords which are never used as table parameters.

Constructor Detail

FitsHeader

public FitsHeader(ParsedCard<?>[] cards)

Constructor. All the header cards composing the header must be included so that the header knows its length in bytes.

Parameters:

cards - header cards composing the header

Method Detail

getCards

public ParsedCard<?>[] getCards()

Returns the header cards of which this header is composed.

Returns:

ordered sequence of parsed header cards

getValue

public java.lang.Object getValue(java.lang.String key)

Returns the untyped value for a card with a given key, if one exists.

Parameters:

key - header keyword

Returns:

value, or null

getDescribedValue

public DescribedValue getDescribedValue(java.lang.String key)

Returns the content of a card with a given key as a DescribedValue, if such a key exists. Any comment text is provided as the ValueInfo.getDescription().

Parameters:

key - header keyword

Returns:

described value, or null

getIntValue

public java.lang.Integer getIntValue(java.lang.String key)

Returns the integer value for a card with a given key, if one exists.

Parameters:

key - header keyword

Returns:

integer value, or null

getLongValue

public java.lang.Long getLongValue(java.lang.String key)

Returns the long value for a card with a given key, if one exists.

Parameters:

key - header keyword

Returns:

long value, or null

getDoubleValue

public java.lang.Double getDoubleValue(java.lang.String key)

Returns the double value for a card with a given key, if one exists.

Parameters:

key - header keyword

Returns:

double value, or null

getNumberValue

public java.lang.Number getNumberValue(java.lang.String key)

Returns a numeric value for a card with a given key, if one exists. This may be a BigInteger or BigDecimal if no other Number class can represent the serialized value.

Parameters:

key - header keyword

Returns:

numeric value, or null

getBooleanValue

public java.lang.Boolean getBooleanValue(java.lang.String key)

Returns the boolean value for a card with a given key, if one exists.

Parameters:

key - header keyword

Returns:

boolean value, or null

getStringValue

public java.lang.String getStringValue(java.lang.String key)

Returns the string value for a card with a given key, if one exists.

Parameters:

key - header keyword

Returns:

string value, or null

getRequiredIntValue

public int getRequiredIntValue(java.lang.String key)
                        throws HeaderValueException

Returns an integer value for a card with a given key, or throws an exception if none exists.

Parameters:

key - header keyword

Returns:

integer value

Throws:

HeaderValueException - if no suitable card exists

getRequiredLongValue

public long getRequiredLongValue(java.lang.String key)
                          throws HeaderValueException

Returns a long value for a card with a given key, or throws an exception if none exists.

Parameters:

key - header keyword

Returns:

long value

Throws:

HeaderValueException - if no suitable card exists

getRequiredStringValue

public java.lang.String getRequiredStringValue(java.lang.String key)
                                        throws HeaderValueException

Returns a long value for a card with a given key, or throws an exception if none exists.

Parameters:

key - header keyword

Returns:

long value

Throws:

HeaderValueException - if no suitable card exists

useKey

public void useKey(java.lang.String key)

Marks a given keyword as used. This is invoked by all the get*Value methods.

Parameters:

key - header keyword

getHeaderBlockCount

public long getHeaderBlockCount()

Returns the number of FITS blocks occupied by this header.

Returns:

number of 2880-byte blocks in header

getDataBlockCount

public long getDataBlockCount()
                       throws HeaderValueException

Returns the number of FITS blocks occupied by the Data part of the HDU described by this header.

Returns:

number of 2880-byte blocks in data part of HDU

Throws:

HeaderValueException

getHeaderByteCount

public long getHeaderByteCount()

Returns the number of bytes occupied by this header, rounded up to an integer number of blocks.

Returns:

getHeaderBlockCount() * 2880

getDataByteCount

public long getDataByteCount()
                      throws HeaderValueException

Returns the number of bytes occupied by the Data part of the HDU described by this header, rounded up to an integer number of blocks.

Returns:

getDataBlockCount() * 2880

Throws:

HeaderValueException

getUnusedParams

public DescribedValue[] getUnusedParams()

Returns an array of DescribedValue objects suitable for use as items of per-table metadata derived from this FITS header. This contains entries for every card which has not already been queried within this object (for which useKey(java.lang.String) has not been explicitly or implicitly called. Certain standard structural FITS keywords (BORING_KEYS) are ignored as well.

The idea is that keywords which have already been read to determine table structure do not need to be recorded separately since their meaning is implicitly included in the table metadata already.

Returns:

array of table parameters relating to this object