Class AbstractFitsTableWriter

java.lang.Object
uk.ac.starlink.table.StreamStarTableWriter
uk.ac.starlink.fits.AbstractFitsTableWriter
All Implemented Interfaces:
uk.ac.starlink.table.MultiStarTableWriter, uk.ac.starlink.table.StarTableWriter
Direct Known Subclasses:
ColFitsTableWriter, FitsTableWriter, HduFitsTableWriter, HealpixFitsTableWriter, VariableFitsTableWriter

public abstract class AbstractFitsTableWriter extends uk.ac.starlink.table.StreamStarTableWriter implements uk.ac.starlink.table.MultiStarTableWriter
Abstract table writer superclass designed for writing FITS tables.

A couple of Auxiliary metadata items of the ColumnInfo metadata from written tables are respected:

  • Tables.NULL_VALUE_INFO: sets the value of TNULLn "magic" blank value for integer columns
  • Tables.UBYTE_FLAG_INFO: if set to Boolean.TRUE and if the column has content class Short or short[], the data will be written as unsigned bytes (TFORMn='B') not 16-bit signed integers (TFORMn='I').
  • BintableStarTable.LONGOFF_INFO: if this is set to a string representation of an integer value, and the column has content class String or String[], then the data will be written as long integers (TFORMn='K') with the given offset (TZEROn=...). This option supports round-tripping of offset long values (typically representing unsigned longs) which are converted to strings on read.
Since:
27 Jun 2006
Author:
Mark Taylor
  • Constructor Details

    • AbstractFitsTableWriter

      protected AbstractFitsTableWriter(String formatName)
      Constructor.
      Parameters:
      formatName - format name
  • Method Details

    • getFormatName

      public String getFormatName()
      Specified by:
      getFormatName in interface uk.ac.starlink.table.StarTableWriter
    • setFormatName

      public void setFormatName(String formatName)
      Sets the declared format name.
      Parameters:
      formatName - format name
    • getMimeType

      public String getMimeType()
      Returns "application/fits".
      Specified by:
      getMimeType in interface uk.ac.starlink.table.StarTableWriter
      Returns:
      MIME type
    • writeStarTable

      public void writeStarTable(uk.ac.starlink.table.StarTable table, OutputStream out) throws IOException
      Specified by:
      writeStarTable in interface uk.ac.starlink.table.StarTableWriter
      Throws:
      IOException
    • writeStarTables

      public void writeStarTables(uk.ac.starlink.table.TableSequence tableSeq, OutputStream out) throws IOException
      Writes tables. Calls writePrimaryHDU(java.io.OutputStream) to write the primary HDU. Subclasses which want to put something related to the input tables into the primary HDU will need to override this method (writeStarTables).
      Specified by:
      writeStarTables in interface uk.ac.starlink.table.MultiStarTableWriter
      Throws:
      IOException
    • writeStarTables

      public void writeStarTables(uk.ac.starlink.table.TableSequence tableSeq, String location, uk.ac.starlink.table.StarTableOutput sto) throws IOException
      Specified by:
      writeStarTables in interface uk.ac.starlink.table.MultiStarTableWriter
      Throws:
      IOException
    • writePrimaryHDU

      public void writePrimaryHDU(OutputStream out) throws IOException
      Writes the primary HDU. This cannot contain a table since BINTABLE HDUs can only be extensions. The AbstractFitsTableWriter implementation writes a minimal, data-less HDU.
      Parameters:
      out - destination stream
      Throws:
      IOException
    • writeTableHDU

      public void writeTableHDU(uk.ac.starlink.table.StarTable table, FitsTableSerializer fitser, OutputStream out) throws IOException
      Writes a data HDU.
      Parameters:
      table - the table to be written into the HDU
      fitser - fits serializer initalised from table
      out - destination stream
      Throws:
      IOException
    • getConfig

      public FitsTableSerializerConfig getConfig()
      Returns the configuration details for writing FITS files. Its content can be controlled using single-config-item mutator methods (which may also be labelled as ConfigMethods) on this class. This covers things that are generally orthogonal to the type of serialization, so may be set for any kind of FITS output, which is why it makes sense to manage them in the AbstractFitsTableWriter abstract superclass.
      Returns:
      object representing the FITS serialization options currently configured for this writer
    • createSerializer

      protected abstract FitsTableSerializer createSerializer(uk.ac.starlink.table.StarTable table) throws IOException
      Provides a suitable serializer for a given table. Note this should throw an IOException if it can be determined that the submitted table cannot be written by this writer, for instance if it has too many columns.
      Parameters:
      table - table to serialize
      Returns:
      FITS serializer
      Throws:
      IOException - if the table can't be written
    • getMetadataCards

      protected List<CardImage> getMetadataCards()
      Adds some standard metadata header cards to a FITS table header. This includes date stamp, STIL version, etc.
      Returns:
      list of cards giving write-specific metadata
    • setWriteDate

      @ConfigMethod(property="date", doc="<p>If true, the DATE-HDU header is filled in with the current date; otherwise it is not included.</p>") public void setWriteDate(boolean writeDate)
      Configures whether a datestamp is written to output FITS files.
      Parameters:
      writeDate - true to include DATE-HDU, false to omit it
    • getWriteDate

      public boolean getWriteDate()
      Indicates whether a datestamp is written to output FITS files.
      Returns:
      true to include DATE-HDU, false to omit it
    • setAllowSignedByte

      public void setAllowSignedByte(boolean allowSignedByte)
      Configures how Byte-valued columns are written. This is a bit fiddly, since java bytes are signed, but FITS 8-bit integers are unsigned. If true, they are written as FITS unsigned 8-bit integers with an offset, as discussed in the FITS standard (TFORMn='B', TZERO=-128). If false, they are written as FITS signed 16-bit integers.
      Parameters:
      allowSignedByte - true to write offset bytes, false to write shorts
    • getAllowSignedByte

      public boolean getAllowSignedByte()
      Returns a flag indicating how Byte-valued columns are written.
      Returns:
      true to write offset bytes, false to write shorts
    • setAllowZeroLengthString

      public void setAllowZeroLengthString(boolean allowZeroLengthString)
      Sets whether zero-length string columns may be written. Such columns (TFORMn='0A') are explicitly permitted by the FITS standard, but they can cause crashes because of divide-by-zero errors when encountered by some versions of CFITSIO (v3.50 and earlier), so FITS writing code may wish to avoid them. If this is set false, then A repeat values will always be >=1.
      Parameters:
      allowZeroLengthString - false to prevent zero-length string columns
    • getAllowZeroLengthString

      public boolean getAllowZeroLengthString()
      Indicates whether zero-length string columns may be output.
      Returns:
      false if zero-length string columns are avoided
    • setWide

      public void setWide(WideFits wide)
      Sets the convention for representing over-wide (>999 column) tables.
      Parameters:
      wide - wide-table representation policy, null to avoid wide tables
    • getWide

      public WideFits getWide()
      Indicates the convention in use for representing over-wide tables.
      Returns:
      wide-table representation policy, null for no wide tables
    • setPadCharacter

      public void setPadCharacter(byte padChar)
      Sets the byte value with which under-length string (character array) values should be padded. This should normally be one of 0x00 (ASCII NUL) or 0x20 (space). The function of an ASCII NUL is to terminate the string early, as described in Section 7.3.3.1 of the FITS 4.0 standard; space characters pad it to its declared length with whitespace. Other values in the range 0x21-0x7E are permitted but probably not sensible.
      Parameters:
      padChar - character data padding byte
    • getPadCharacter

      public byte getPadCharacter()
      Returns the byte value with which under-length string (character array) values will be padded. This will normally be one of 0x00 (ASCII NUL) or 0x20 (space).
      Returns:
      character data padding byte
    • getCurrentDate

      public static String getCurrentDate()
      Returns an ISO-8601 data string representing the time at which this method is called.
      Returns:
      date string