Jena assembler quickstart

Jena’s assembler provides a means of constructing Jena models according to a recipe, where that recipe is itself stated in RDF. This is the Assembler quickstart page. For more detailed information, see the Assembler howto or Inside assemblers.

What is an Assembler specification?

An Assembler specification is an RDF description of how to construct a model and its associated resources, such as reasoners, prefix mappings, and initial content. The Assembler vocabulary is given in the Assembler schema, and we’ll use the prefix ja for its identifiers.

What is an Assembler?

An Assembler is an object that implements the Assembler interface and can construct objects (typically models) from Assembler specifications. The constant Assembler.general is an Assembler that knows how to construct some general patterns of model specification.

How can I make a model according to a specification?

Suppose the Model M contains an Assembler specification whose root - the Resource describing the whole Model to construct is R (so R.getModel() == M). Invoke:


The result is the desired Model. Further details about the Assembler interface, the special Assembler general, and the details of specific Assemblers, are deferred to the Assembler howto.

How can I specify …

In the remaining sections, the object we want to describe is given the root resource my:root.

… a memory model?

my:root a ja:MemoryModel.

… an inference model?

    ja:reasoner [ja:reasonerURL theReasonerURL] ;
    ja:baseModel theBaseModelResource

theReasonerURL is one of the reasoner (factory) URLs given in the inference documentation and code; theBaseModelResource is another resource in the same document describing the base model.

… some initialising content?

    ja:content [ja:externalContent <someContentURL>]
    ... rest of model specification ...

The model will be pre-loaded with the contents of someContentURL.

… an ontology model?

    ja:ontModelSpec ja:OntModelSpecName ;
    ja:baseModel somebaseModel

The OntModelSpecName can be any of the predefined Jena OntModelSpec names, eg OWL_DL_MEM_RULE_INF. The baseModel is another model description - it can be left out, in which case you get an empty memory model. See Assembler howto for construction of non-predefined OntModelSpecs.