nom.tam.fits
Class Header

java.lang.Object
  nom.tam.fits.Header

public class Header

extends Object

This class describes methods to access and manipulate the header for a FITS HDU.

Constructor Summary

Header()
Create a Header with no card images.

Header(BufferedDataInputStream is)
Create a header and populate it from the input stream

Header(String[] newCards)
Create a header and initialize it with a vector of strings.

Method Summary

void	addBooleanValue(String key, boolean val, String comment) Add or replace a key with the given boolean value and comment.
void	addDoubleValue(String key, double val, String comment) Add or replace a key with the given double value and comment.
void	addFloatValue(String key, float val, String comment) Add or replace a key with the given float value and comment.
void	addIntValue(String key, int val, String comment) Add or replace a key with the given int value and comment.
protected void	addLine(HeaderCard fcard) Add a card image to the header after the mark if set.
protected void	addLine(String card) Add a card image to the header after the mark if set.
void	addLongValue(String key, long val, String comment) Add or replace a key with the given long value and comment.
void	addStringValue(String key, String val, String comment) Add or replace a key with the given string value and comment.
(package private) void	checkEnd() Ensure that the header has exactly one END keyword in the appropriate location.
boolean	containsKey(String key) Tests if the specified keyword is present in this table.
void	deleteKey(String key) Delete the card associated with the given key.
protected void	dumpHeader(PrintStream ps) Dump the header to a given stream.
protected HeaderCard	findCard(String key) Find the card associated with a given key.
String	findKey(String key) Find the card associated with a given key.
static String	formatFields(String key, String val, String comment) Format the key, value and comment fields for the FITS data.
boolean	getBooleanValue(String key) Get the boolean value associated with the given key.
boolean	getBooleanValue(String key, boolean dft) Get the boolean value associated with the given key.
String	getCard(int n) Get the n'th card image in the header
double	getDoubleValue(String key) Get the double value associated with the given key.
double	getDoubleValue(String key, double dft) Get the double value associated with the given key.
float	getFloatValue(String key) Get the float value associated with the given key.
float	getFloatValue(String key, float dft) Get the float value associated with the given key.
int	getIntValue(String key) Get the int value associated with the given key.
int	getIntValue(String key, int dft) Get the value associated with the key as an int.
String	getKey(int n) Get the n'th key in the header.
long	getLongValue(String key) Get the long value associated with the given key.
long	getLongValue(String key, long dft) Get the long value associated with the given key.
int	getMark() Get the current mark.
String	getStringValue(String key) Get the String value associated with the given key.
int	headerSize() Return the size of the header data including padding.
protected boolean	imageToPrimary() See if the current header is for an an array and if so turn it into a primary array.
void	insertCard(String card) Insert or add a card to the header.
void	insertComment(String value) Add a COMMENT line.
void	insertCommentStyle(String header, String value) Add a line to the header using the COMMENT style, i.e., no '=' in column 9.
void	insertHistory(String value) Add a HISTORY line.
boolean	isValidHeader() Is this a valid header.
boolean	markSet() Is the mark set?
(package private) void	nullImage() Create a header for a null image.
int	paddedDataSize() Return the size of the data including any needed padding.
void	pointToData(Data o) Create keywords such that this Header describes the given data.
protected void	pointToImage(Object o) Create keywords such that this header describes the given image data.
protected boolean	primaryToImage() See if the current header is an array and if so turn it into an IMAGE extension.
void	read(BufferedDataInputStream dis) Read a stream for header data.
static Header	readHeader(BufferedDataInputStream dis) Create a header by reading the information from the input stream.
void	removeCardAt(int i) Remove the card at the given index.
void	replaceCard(String key, String val, String comment) Add or replace a key using the preformatted value.
(package private) boolean	replaceKey(String oldKey, String newKey) Replace the key with a new key.
(package private) void	setBitpix(int val) Set the BITPIX value for the header.
(package private) void	setExtend(boolean val) Set the EXTEND keyword.
(package private) void	setGcount(int val) Set the group count (GCOUNT) keyword.
void	setMark(int newMark) Set the mark to the given value.
(package private) void	setNaxes(int val) Set the value of the NAXIS keyword
(package private) void	setNaxis(int dim, int val) Set the NAXISn keywords.
(package private) void	setPcount(int val) Set the Parameter count (PCOUNT) keyword.
(package private) void	setSimple(boolean val) Set the SIMPLE keyword to the given value.
(package private) void	setXtension(String val) Set the XTENSION keyword to the given value.
int	size()
int	trueDataSize() Calculate the unpadded size of the data segment from the header information.
void	unsetMark() Unset the mark.
void	write(BufferedDataOutputStream dos) Write the current header (including any needed padding) to the output stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

Header

public Header()

Create a Header with no card images.

Header

public Header(BufferedDataInputStream is)
       throws TruncatedFileException,
              IOException

Create a header and populate it from the input stream

Parameters:

is - The input stream where header information is expected.

Header

public Header(String[] newCards)

Create a header and initialize it with a vector of strings.

Parameters:

newCards - Card images to be placed in the header.

Method Detail

size

public int size()

trueDataSize

public int trueDataSize()

Calculate the unpadded size of the data segment from the header information. Note that this algorithm is not correct for Random Groups format data.

Returns:

the unpadded data segment size.

paddedDataSize

public int paddedDataSize()

Return the size of the data including any needed padding.

Returns:

the data segment size including any needed padding.

headerSize

public int headerSize()

Return the size of the header data including padding.

Returns:

the header size including any needed padding.

isValidHeader

public boolean isValidHeader()

Is this a valid header. This routine provides only minimal checking currently.

Returns:

true for a valid header, false otherwise.

getCard

public String getCard(int n)

Get the n'th card image in the header

Returns:

the card image; return null if the n'th card does not exist.

getKey

public String getKey(int n)

Get the n'th key in the header.

Returns:

the card image; return null if the n'th key does not exist.

getLongValue

public long getLongValue(String key,
                         long dft)

Get the long value associated with the given key.

Parameters:

key - The header key.

dft - The default value to be returned if the key cannot be found.

Returns:

the associated value.

getDoubleValue

public double getDoubleValue(String key,
                             double dft)

Get the double value associated with the given key.

Parameters:

key - The header key.

dft - The default value to return if the key cannot be found.

Returns:

the associated value.

getBooleanValue

public boolean getBooleanValue(String key,
                               boolean dft)

Get the boolean value associated with the given key.

Parameters:

key - The header key.

dft - The value to be returned if the key cannot be found or if the parameter does not seem to be a boolean.

Returns:

the associated value.

getLongValue

public long getLongValue(String key)

Get the long value associated with the given key.

Parameters:

key - The header key.

Returns:

The associated value or 0 if not found.

getDoubleValue

public double getDoubleValue(String key)

Get the double value associated with the given key.

Parameters:

key - The header key.

Returns:

The associated value or 0.0 if not found.

getBooleanValue

public boolean getBooleanValue(String key)

Get the boolean value associated with the given key.

Returns:

The value found, or false if not found or if the keyword is not a logical keyword.

getIntValue

public int getIntValue(String key,
                       int dft)

Get the value associated with the key as an int.

Parameters:

key - The header key.

dft - The value to be returned if the key is not found.

getIntValue

public int getIntValue(String key)

Get the int value associated with the given key.

Parameters:

key - The header key.

Returns:

The associated value or 0 if not found.

getFloatValue

public float getFloatValue(String key,
                           float dft)

Get the float value associated with the given key.

Parameters:

key - The header key.

dft - The value to be returned if the key is not found.

getFloatValue

public float getFloatValue(String key)

Get the float value associated with the given key.

Parameters:

key - The header key.

Returns:

The associated value or 0.0 if not found.

getStringValue

public String getStringValue(String key)

Get the String value associated with the given key.

Parameters:

key - The header key.

Returns:

The associated value or null if not found or if the value is not a string.

addLine

protected void addLine(HeaderCard fcard)

Add a card image to the header after the mark if set.

Parameters:

fcard - The card to be added.

addLine

protected void addLine(String card)
                throws HeaderCardException

Add a card image to the header after the mark if set.

Parameters:

card - The card to be added.

Throws:

HeaderCardException - If the card is not valid.

readHeader

public static Header readHeader(BufferedDataInputStream dis)
                         throws TruncatedFileException,
                                IOException

Create a header by reading the information from the input stream.

Parameters:

dis - The input stream to read the data from.

Returns:

null if there was a problem with the header; otherwise return the header read from the input stream.

Throws:

TruncatedFileException

IOException

read

public void read(BufferedDataInputStream dis)
          throws TruncatedFileException,
                 IOException

Read a stream for header data.

Parameters:

dis - The input stream to read the data from.

Returns:

null if there was a problem with the header; otherwise return the header read from the input stream.

Throws:

TruncatedFileException

IOException

findCard

protected HeaderCard findCard(String key)

Find the card associated with a given key. If found this sets the mark to the card, otherwise it unsets the mark.

Parameters:

key - The header key.

Returns:

null if the keyword could not be found; return the HeaderCard object otherwise.

findKey

public String findKey(String key)

Find the card associated with a given key. If found this sets the mark to the card, otherwise it unsets the mark.

Parameters:

key - The header key.

Returns:

null if the keyword could not be found; return the card image otherwise.

replaceKey

boolean replaceKey(String oldKey,
                   String newKey)
             throws HeaderCardException

Replace the key with a new key. Typically this is used when deleting or inserting columns so that TFORMx -> TFORMx-1

Parameters:

oldKey - The old header keyword.

newKey - the new header keyword.

Returns:

true if the card was replaced.

Throws:

HeaderCardException - If newKey is not a valid FITS keyword.

write

public void write(BufferedDataOutputStream dos)
           throws FitsException

Write the current header (including any needed padding) to the output stream.

Parameters:

dos - The output stream to which the data is to be written.

Throws:

FitsException - if the header could not be written.

addBooleanValue

public void addBooleanValue(String key,
                            boolean val,
                            String comment)
                     throws HeaderCardException

Add or replace a key with the given boolean value and comment.

Parameters:

key - The header key.

val - The boolean value.

comment - A comment to append to the card.

Throws:

HeaderCardException - If the parameters cannot build a valid FITS card.

addFloatValue

public void addFloatValue(String key,
                          float val,
                          String comment)
                   throws HeaderCardException

Add or replace a key with the given float value and comment.

Parameters:

key - The header key.

val - The float value.

comment - A comment to append to the card.

Throws:

HeaderCardException - If the parameters cannot build a valid FITS card.

addDoubleValue

public void addDoubleValue(String key,
                           double val,
                           String comment)
                    throws HeaderCardException

Add or replace a key with the given double value and comment.

Parameters:

key - The header key.

val - The double value.

comment - A comment to append to the card.

Throws:

HeaderCardException - If the parameters cannot build a valid FITS card.

addStringValue

public void addStringValue(String key,
                           String val,
                           String comment)
                    throws HeaderCardException

Add or replace a key with the given string value and comment.

Parameters:

key - The header key.

val - The string value.

comment - A comment to append to the card.

Throws:

HeaderCardException - If the parameters cannot build a valid FITS card.

replaceCard

public void replaceCard(String key,
                        String val,
                        String comment)
                 throws HeaderCardException

Add or replace a key using the preformatted value. If the key is not found, then add the card after the current mark or at the end if the mark is not set.

Parameters:

key - The header key.

val - The string which will follow the "= " on the card. This routine is called by the various addXXXValue routines after they have formatted the value as a string.

comment - A comment to append to the card.

Throws:

HeaderCardException - If the parameters cannot build a valid FITS card.

addIntValue

public void addIntValue(String key,
                        int val,
                        String comment)
                 throws HeaderCardException

Add or replace a key with the given int value and comment.

Parameters:

key - The header key.

val - The int value.

comment - A comment to append to the card.

Throws:

HeaderCardException - If the parameters cannot build a valid FITS card.

addLongValue

public void addLongValue(String key,
                         long val,
                         String comment)
                  throws HeaderCardException

Add or replace a key with the given long value and comment.

Parameters:

key - The header key.

val - The long value.

comment - A comment to append to the card.

Throws:

HeaderCardException - If the parameters cannot build a valid FITS card.

formatFields

public static String formatFields(String key,
                                  String val,
                                  String comment)
                           throws HeaderCardException

Format the key, value and comment fields for the FITS data.

Parameters:

key - The header keyword.

val - The value associated with the key expressed as a string.

comment - A comment to put on the field.

Throws:

HeaderCardException - If the parameters cannot build a valid FITS card.

insertCard

public void insertCard(String card)

Insert or add a card to the header. Insert after the mark if set, or at the end of the header if not set.

Parameters:

card - The card to be inserted.

insertCommentStyle

public void insertCommentStyle(String header,
                               String value)
                        throws HeaderCardException

Add a line to the header using the COMMENT style, i.e., no '=' in column 9.

Parameters:

header - The comment style header.

value - A string to follow the header.

Throws:

HeaderCardException - If the parameters cannot build a valid FITS card.

insertComment

public void insertComment(String value)
                   throws HeaderCardException

Add a COMMENT line.

Parameters:

value - The comment.

Throws:

HeaderCardException - If the parameter is not a valid FITS comment.

insertHistory

public void insertHistory(String value)
                   throws HeaderCardException

Add a HISTORY line.

Parameters:

value - The history record.

Throws:

HeaderCardException - If the parameter is not a valid FITS comment.

markSet

public boolean markSet()

Is the mark set?

Returns:

true if the mark is set.

getMark

public int getMark()

Get the current mark. A value of -2 indicates that the mark is not set and new cards are appended to the end of the header. A value of -1 indicates that the mark is set such that the next card should be inserted at the beginning of the header. Otherwise cards should be inserted after the mark. The mark is typically set to a card whenever an operation (i.e., insert or modify) is made on the card. Thus a series of inserts will result in cards a sequential series of cards in the same order.

Returns:

the current mark.

setMark

public void setMark(int newMark)

Set the mark to the given value.

unsetMark

public void unsetMark()

Unset the mark. Inserts should now be done as appends to the end of the header.

deleteKey

public void deleteKey(String key)

Delete the card associated with the given key. Nothing occurs if the key is not found, though this will unset the mark. The mark is left pointing at the following card if successful (or unset if this was the last card).

Parameters:

key - The header key.

removeCardAt

public void removeCardAt(int i)

Remove the card at the given index. The mark is left pointing at the next card or unset if this was the last card.

Parameters:

i - The index of the card to be removed.

containsKey

public final boolean containsKey(String key)

Tests if the specified keyword is present in this table.

Parameters:

key - the keyword to be found.

Returns:

true if the specified keyword is present in this table; false otherwise.

pointToData

public void pointToData(Data o)
                 throws FitsException

Create keywords such that this Header describes the given data.

Parameters:

o - The data object to be described.

Throws:

FitsException - if the data was not valid for this header.

pointToImage

protected void pointToImage(Object o)
                     throws FitsException

Create keywords such that this header describes the given image data.

Parameters:

o - The image to be described.

Throws:

FitsException - if the object does not contain valid image data.

nullImage

void nullImage()

Create a header for a null image.

setSimple

void setSimple(boolean val)

Set the SIMPLE keyword to the given value.

Parameters:

val - The boolean value -- Should be true for FITS data.

setXtension

void setXtension(String val)

Set the XTENSION keyword to the given value.

Parameters:

val - The name of the extension. "IMAGE" and "BINTABLE" are supported.

setBitpix

void setBitpix(int val)

Set the BITPIX value for the header.

setNaxes

void setNaxes(int val)

Set the value of the NAXIS keyword

Parameters:

val - The dimensionality of the data.

checkEnd

void checkEnd()

Ensure that the header has exactly one END keyword in the appropriate location.

setNaxis

void setNaxis(int dim,
              int val)

Set the NAXISn keywords.

Parameters:

dim - The dimension being set.

val - The length along that dimension.

setGcount

void setGcount(int val)

Set the group count (GCOUNT) keyword. This should be 1 except for the unsupported random-groups data.

Parameters:

val - the number of groups in the data.

setPcount

void setPcount(int val)

Set the Parameter count (PCOUNT) keyword. This is normally 0 except when random-groups data is used or when the variable length columns convention is used with binary tables.

Parameters:

val - The number of parameters.

setExtend

void setExtend(boolean val)

Set the EXTEND keyword. This is only placed in the primary header and should always be true. Just in case we do provide for setting it to false.

Parameters:

val - the value assigned to the EXTEND keyword.

primaryToImage

protected boolean primaryToImage()

See if the current header is an array and if so turn it into an IMAGE extension.

Returns:

whether the transformation could be done.

imageToPrimary

protected boolean imageToPrimary()

See if the current header is for an an array and if so turn it into a primary array.

Returns:

whether the transformation could be done.

dumpHeader

protected void dumpHeader(PrintStream ps)

Dump the header to a given stream.

Parameters:

ps - the stream to which the card images are dumped.