Sesame 2 Desktop Client

I recently needed a programming excercise in creating a Windows graphical user interface, and decided to create a simple Sesame 2 client. This has turned out to become quite a useful little tool so I've decided to make it available open source.

The Sesame 2 desktop client is a windows (.Net) application that can communicate with a (remote) Sesame 2 server, perform queries, add/remove data, and so on. It is somewhat similar to the Sesame Workbench application, but it has a couple of nice user-friendly options (such as implicit adding of namespace declarations to your queries, dynamic sorting of the query result, etc).

You can download it from sourceforge. Give it a spin, tell me what you think, suggestions most welcome!

Of and of course my thanks to the dotSesame people, whose work I've gratefully reused in this tool.

Sesame 2.0 final released (while you weren't looking...)

While everybody was busy stocking food and drink, the Sesame developers apparently have been at it in overdrive, managing to release the final release of Sesame 2.0 just in time for Christmas. From the openRDF.org announcement:

"Thanks to an overwhelming number of people that have tested the previous release candidates and reported any issues that surfaced, we can now proudly present Sesame, version 2.0!

After the second release candidate, only one serious issue was reported and fixed. We found and fixed some minor, non-critical issues ourselves and made some small improvements here and there, mostly related to HTTP communication and OpenRDF Workbench. All in all, we think the code is now sufficiently tested to call it 2.0-final.

The development focus will now shift to performance and scalability improvements. An RDBMS-based Sail implementation is currently under development and the first results look very promising. The performance of the native- and memory stores will also be improved. As there hasn't been put a lot of effort into this so far, we expect to achieve good results here."

I just want to take the opportunity to congratulate the people at Aduna with this important milestone! Great job, and thanks!

.Net is truly like a foreign country...

...they do things exactly the same there.

I have recently been involved in a project where an RDF ontology + instance set needs to be exposed through a web UI. Being a Java man myself I was immediately set to start fiddling about with JSP/JSF, Spring MVC and (obviously) a Sesame 2 store.

However, in this project my coworkers are .Net developers, so we were left with either me doing all the work myself or somehow figuring out a way of using a Sesame store in a .Net environment. Given that I only have one brain and two arms, and the project has a deadline that falls within the first half of this century, we decided to go for the second option. The web frontent will be in ASP/.Net, the server backend will run Sesame in Java. So, how to get them to talk?

Our first attempt involved using Spring-WS to write a Web Services wrapper (SOAP messaging, WSDL description, the works) around the Sesame store. However, this wrapper was application-specific (talking in terms of business objects from the application domain rather than being a generic sesame wrapper), and really rather large, clumsy and difficult to maintain, so we decided to try something else.

Enter IKVM.net. This is a Java implementation for Mono and .Net that can also be used to do a static porting of Java classes to .Net bytecode (or CIL as they call it in .Net-land). Using a handy little tool called ikvmc I managed (in about half an hour time, mostly spent on trying to figure out which of Sesame 2's impressive collection of jar files to in- and exclude from the process) to create a DLL and he presto! A Sesame 2-compatible HTTP Repository proxy API for .Net Is Born!

Using this DLL we can now access, in C#, a remote Sesame server in exactly the same fashion as we would from a Java environment: by simply using Sesame's own Repository API.

Perhaps not the most elegant and robust solution - and not nearly as much fun as spending several man-months on painstakingly building a .Net client library from scratch, including the creation of parsers and writers for N3, Turtle, RDFXML, Trig, TriX, SPARQL XML result format, SPARQL, SeRQL, and Sesame 2's transaction serialization format - but in a pinch and on a tight budget quite a satisfactory little workaround.