Java library to query DAL services?

[Mark Taylor]

Thomas,

On Mon, 4 Apr 2016, Thomas Boch wrote:

> I am interested in Java libraries I could use out of the box to query DAL
> services (cone search, SIA, SSA or TAP).
> Any advice or suggestion would be of great help.
> Thank you.

most of the DAL client code in topcat/stilts is in the java namespace
uk.ac.starlink.vo.  These classes are deliberately intended for
use outside of stilts or topcat (though I'm not sure anybody else
has so used them to date), so they don't have dependencies
on application code.  Of course it's all open source (LGPL I think)
and comes with what I hope are fairly comprehensive javadocs.

However, I haven't gone to the trouble of actually packaging
these classes up into a separate jar file with dependencies,
so a little bit of deployment work would be required if you wanted
to use them.  For now, you can find them bundled up in the stilts
or topcat standalone jar files, or build them yourself from github.
There is a dependency on the (not too big) uk.ac.starlink.util package.
The other main dependency is on STIL, the table handling library.
This is partly for VOTable handling, and partly because some of
these classes (e.g. for TAP queries) generate
uk.ac.starlink.table.StarTable instances as their basic output.

You can find javadocs (for some undefined reasonably-recent version)
here:

   http://andromeda.star.bris.ac.uk/starjavadocs/

The VO package includes:

   UwsJob:
      UWS client and utilities
   TapQuery:
      TAP sync/async job submission/result retrieval and utilities
   RegistryProtocol:
      RegTAP (and RI1.0) registry queries
   ConeSearch:
      Prepares, submits and retrieves cone searches
   DalQuery (and DalResultXMLFilter):
      Submits S*AP queries and processes XML output looking for results
   TapTableLoadDialog:
      Full TAP GUI (as seen in TOPCAT's TAP load dialogue)
   S*apTAbleLoadDialog:
      Full GUI for single SIAP/SSAP searches

and, well, a load of other stuff that these and most of the rest of
the VO functionality in topcat and stilts are built on.

I'm very happy to to provide whatever detailed advice you (or anybody
else) need to make use of these classes or investigate further
whether they'd suit your requirements.  I can either do it by email
on- or off-list, or we can sit down together in Cape Town.

Mark

--
Mark Taylor   Astronomical Programmer   Physics, Bristol University, UK
m.b.taylor at bris.ac.uk +44-117-9288776  http://www.star.bris.ac.uk/~mbt/