<p xmlns="http://www.w3.org/1999/xhtml"> SCB comprises the following architectural components as depicted in Fig. 1: </p> <ul xmlns="http://www.w3.org/1999/xhtml"> <li>Core</li> <li>Facades</li> <li>Utilities</li> <li>Storage Providers</li> <li>Parsing Providers</li> <li>Serializing Providers</li> <li>Ontologies Tool</li> </ul> <p xmlns="http://www.w3.org/1999/xhtml"> <img alt="SCB Architecture" src="images/scb_architecture.png"/> <br/><i>Figure 1: SCB Architecture</i> </p> <p xmlns="http://www.w3.org/1999/xhtml"> The Core contains interface definitions of the RDF graph data model and its implementation. The three main classes are <code>Graph</code>, <code>MGraph</code>, and <code>TripleCollection</code>. The class <code>Graph</code> represents an immutable RDF Graph, as such its identity criterion is defined in terms of graph-isomorphism. The class <code>MGraph</code> represents a mutable RDF Graph, which enables triples to be added to or removed from a graph. The class <code>TripleCollection</code> is the super class of both the class <code>Graph</code> and <code>M</code><code/><code/><code/><code/><code/><code/><code/><code>Graph</code>. SCB Core provides three services: <code>TcManager</code> [<a href="#ref4">4</a>] allows access to the various <code>TripleCollection</code>s, <code>Parser</code> [<a href="#ref5">5</a>] and <code>Serializer</code> [<a href="#ref6">6</a>] to allow reading and writing graphs from and to various formats. In an OSGi environment these services are accessed using the service registry or injected using OSGi Declarative Services. In a non OSGi environment static factory methods are used to return an instance. The <code>TcManager</code> delegates actual processing tasks to a specific Storage Provider chosen from a set of Storage Providers based on their priority number (weight). Storage Providers can be dynamically bound to or unbound from the Core. The functionality required by the Parser and Serializer is delegated to registered Parsing and Serializing Providers respectively, according to their capability (supported formats). Later registered providers shadow previous ones for the same format. </p> <p xmlns="http://www.w3.org/1999/xhtml"> The current implementation of SCB includes a Jena Façade. The Jena Façade allows an application to use Jena API to manipulate a TC. </p> <p xmlns="http://www.w3.org/1999/xhtml"> In order to ease operations on a resource in a TC, the Utilities component provides a class with a set of useful methods, e.g., to delete all triples (statements) with the resource as subject and a specified predicate. </p> <p xmlns="http://www.w3.org/1999/xhtml"> Finally, the Ontologies Tool contains a standalone application called SchemaGen to generate the Java source code with constants from an ontology description. </p> 1