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C.1 Version History

Version 1.0 (30 Jan 2004)
Initial public release.
Version 1.0-2 (11 Feb 2004)
Version 1.0-3 (12 Feb 2004)
Version 1.0-4 (17 Mar 2004)
Version 1.1 (29 Mar 2004)
Version 1.1-1 (11 May 2004)
Version 2.0 (October 2004)
Version 2.0 is a major revision incorporating some non-backwardly-compatible changes to the public API. The main differences are as follows.
RowSequence interface modified
The RowSequence interface has been modified; a new close method has been introduced, and the old advance() and getRowIndex() methods have been withdrawn (these latter were not very useful and in some cases problematic to implement).
Setter methods added to StarTable interface
The methods setName() and setURL() have been added to the StarTable interface.
Pluggable storage policies
The StoragePolicy class was introduced, which allows you to influence whether cached table data are stored in memory or on disk. This has led to backwardly-incompatible changes to public interfaces and classes: makeStarTable now takes a new StoragePolicy argument, and VOElementFactory's methods are now instance methods rather than static ones.
Input table format now either specified explicitly or detected automatically
The StarTableFactory class's makeStarTable methods now come in two flavours - with and without a format name. This corresponds to two table reading modes: named format mode and automatic format detection mode. In named format mode you specify the format of the table you are trying to read and in automatic format detection mode you rely on the factory to work it out using magic numbers. Although automatic detection works well for VOTable and FITS, it's poor for text-based formats like ASCII and CSV. This has resulted in addition of some new two-argument makeStarTable methods and the withdrawal of the getBuilders method in favour of two new methods getDefaultBuilders and getKnownBuilders (similarly for setter methods) which deal with the handlers used in automatic detection mode and the ones available for named format mode respectively. Note that the ASCII table format is not automatically detected, so to use ASCII tables you now have to specify the format explicitly.
VOTable parsing overhauled
The VOElement class has been rewritten and now implements the DOM Element interface. This means that the hierarchical structure which you can navigate to obtain information about the VOTable document and extract table data actually is a DOM rather than just being sat on top of one. You can therefore now use it just as a normal DOM tree (making use of the methods defined in the org.w3c.dom interface, interoperating with third-party components which require a DOM). This has had a number of additional benefits and consequences:
  • VOTable handling now fully meets version 1.1 of the VOTable standard. This includes full ID/ref crossreferencing (e.g. a TABLE element obtaining its structure by reference to a previously defined one) which was absent in previous versions.
  • VOTable processing is now independent of Java version; in previous versions it failed on J2SE1.5/5.0 due to absence of some Crimson parser classes.
  • The VOElementFactory class now has instance methods rather than static methods.
  • By installing a StoragePolicy.DISCARD into a VOElementFactory it is now possible to obtain a data-less (structure only, hence minimal resource) VOTable DOM.
TableSink interface modified
Some TableSink methods now throw exceptions.
Comma-Separated Value format supported
There are now CSV input and output handlers. The input handler is not by default installed in the StarTableFactory's list for automatic format detection, but CSV-format tables can be loaded using named format mode. The format is intended to match the (widely-used) variety used by Microsoft Excel amongst others (with optional column names).
New 'FITS-plus' format introduced
Handlers are introduced for a variant of FITS called 'FITS-plus' (see Section 3.5.2). This is a FITS file with a BINTABLE extension in HDU#1 as usual, but with the VOTable text containing its metadata stored in a byte array in the primary HDU. This means that the rich VOTable metadata are available when reading it with a matching input handler, but it looks like a perfectly normal FITS table without the metadata when read by a normal FITS-aware application. This is now the format in which FITS tables are written by default (unless you choose the format name "basic-fits").
ASCII-format input handler improvements
  • Now runs in limited memory, but requires two passes of stream (data caching as per current StoragePolicy).
  • Now uses Short/Float types in preference to Integer/Double if the input data make this appropriate.
  • Now preserves negative zero values (often important for sexagesimal representations).
  • Now understands d or D as an exponent letter as well as e or E.
  • A '!' character in column 1 is now understood to introduce a comment line.
Table matching
There have been several changes including performance enhancements and improved functionality in the table matching classes in the package uk.ac.starlink.table.join. These work and have full javadocs, but they are still experimental, subject to substantial change in future releases, and not documented properly in this document.
Null handling improvements
There is now a mechanism for flagging the magic value you would like to use when encoding nulls in an integer output column (NULL_VALUE_INFO) Nulls in FITS and VOTable/FITS tables are now preserved correctly on output.
Miscellaneous
There have been a number of miscellaneous improvements and bugfixes in various parts of the library, including the following:
  • FITS files now store column descriptions in TCOMMx headers.
  • A type-translation bug in the JDBC handler has been fixed, so that it now works with PostgreSQL (and possibly other JDBC implementations).
  • New class EmptyStarTable added.


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STIL - Starlink Tables Infrastructure Library
Starlink User Note 252
STIL web page: http://www.starlink.ac.uk/stil/
Author email: m.b.taylor@bristol.ac.uk
Starlink: http://www.starlink.ac.uk/