Sesame 4.0 was officially released today. This first new major release of the Sesame RDF framework in over 7 years focuses on major usability improvements in the core APIs. In particular, its goals are to reduce boilerplate code in Sesame-based projects, and to facilitate easier, more flexible, and streaming access to RDF data and query results. To this end, release 4 uses several new features of the Java 8 platform, such as lambda expressions, the Stream API, and the AutoCloseable interface.

The Sesame Programmers Manual gives an overview of what these changes entail. However, to illustrate how much of a difference these changes can make for even very simple code, I will show off some of the features in more detail here.

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The Sesame Native Store is reported to scale up to about 100-150 million triples (depending on hardware and dataset characteristics). However, getting that number of triples into the store is not always a trivial task, so I wanted to go over several possible strategies you can employ to get best performance when trying to upload large datasets into the Sesame Native Store.

In this recipe, we will look at simple uploading and its limitations, splitting your input data into several files (and how to deal with blank node identity), as well programmatically chunked uploads and several tweaks you can emply to improve performance.

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The SPARQL query language is extensible by nature: it allows implementors to define their own custom operators if the standard set of operators is not sufficient for the needs of some application.

Sesame’s SPARQL engine has been designed with this extensibility in mind: it allows you to define your own custom functions and use them as part of your SPARQL queries, like any other function. In this new recipe, I’ll show how to create a simple custom function. Specifically, we are going to implement a boolean function that detects if some string literal is a palindrome. read more…

I have finally found the time to set up my new weblog and website for Rivuli Development. Rivuli Development is all about the use of semantic technologies: RDF, SPARQL, Linked Data, and so on. In other words, it is about what I do as a freelance technical consultant and software developer.

Currently, the content is still a bit sparse, but you can expect regular blog postings here on topics such as software design and implementation for SPARQL 1.1, usage tips and tricks for the Sesame framework, and more general musings on Semantic Web and Linked Data. I will also further extend the site with additional static content, including more general information about what linked data and semantic web are all about, and what advantages these technologies can provide to business.