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Date: Tue, 13 Nov 2012 14:41:19 +0100
From: Minto van der Sluis <minto@xup.nl>
Organization: Xup BV
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To: clerezza-dev@incubator.apache.org
Subject: Questions related to using clerezza components
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Hi folks,

Being new to Clerezza I wonder if part of Clerezza can be used to
support my current situation. I need to create an RDF-store with some
logic around it. So far I came up with the following:

1) A processing engine/pipeline with basically 2 operations Put and Select.
2) The pipeline contains functional units like:  authorisation (A),
processing (P), validation (V), storage (S) and filtering (F)
3) Put-operation takes a RDF Graph as input and pushes it into the
processing pipeline (A -> P -> V -> S)
4) Every Put contains a fragment (but still a Graph) of a namespace/context.
5) These fragments need to be accumulated into a single Graph per
namespace/context.
5) Select-operation takes a (named) query (probably sparql) and pushes
it into the processing pipeline (A -> S -> F)
6) Select returns one or more of these accumulated graphs.
7) The functional units are pluggable with support for more than one
unit of the same type.

Now I had the following in mind for using Clerezza components:

- Clerezza Parser (rdf.core) for creating the RDF Graph in memory to
start the Put pipeline.
- Maybe using Apache Stanbol OntologyManager in the Validation unit to
validate Graph content against predefined ontologies.
- One of the Clerezza storage components (probably Jena Tdb) to do the
actual persistent storage and retrieval in the Storage unit.
- Clerezza SerializingProvider (rdf.core) for serializing the results
from the Select-operation.

Looking at Clerezza I greatly appreciate the abstractness from the
underlying storage implementation (Jena, Sesame). However I have the
impression that the Parser (rdf.core) immediately stores the Graph in
the persistent storage. Is that correct? If so, how can I use the parser
to first create a Graph in memory. And, later (when all criteria are
met) store this memory graph into a storage component like Tdb (I can't
find a suitable operation on TdbTcProvider).

My apologies for being abstract, but I am not allowed (NDA) to give to
many details.

Any advice is highly appreciated.

Regards,

Minto

-- 
ir. ing. Minto van der Sluis
Software innovator / renovator
Xup BV