Package uk.ac.starlink.fits

Class 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
    Author:
    Mark Taylor

    • Field Summary

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

    • Constructor Summary

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

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method 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.
      uk.ac.starlink.table.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.
      uk.ac.starlink.table.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 uk.ac.starlink.table.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

      • getUnusedParams

        public uk.ac.starlink.table.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