RDFPRO: an extensible tool for building stream-oriented RDF processing pipelines.

We present RDF PRO (RDF Processor), an open source Java command line tool and embeddable library that offers a suite of stream-oriented, highly optimized processors for common tasks such as data filtering, RDFS inference, smushing and statistics extraction. RDF PRO processors are extensible by users and can be freely composed to form complex pipelines to efficiently process RDF data in one or more passes. We show how RDF PRO model and multi-threaded design allow processing billions of triples in few hours in a typical Linked Open Data integration scenario, and discuss relevant implementation aspects and lessons learnt.