∇ Switch Schema Display To Condensed ∇ Switch Schema Display To N3 ∇ Print Current Display


table of contents

table of contents
introduction
overview
specifications common to all models
content
RDB models and Connections
file models
inference models and reasoners
ReasonerFactory
rulesets
ontology models
document managers
union models
prefix mappings
other Assembler directives
assembler
imports
limited RDFS inference

introduction

This document describes the vocabulary and effect of the built-in Jena assembler descriptions for constructing models (and other things). A companion document describes the built-in assembler classes and how to write and integrate your own assemblers. If you just need a quick guide to the common model specifications, see the assembler quickstart.

This document describes how to use the Assembler classes to construct models -- and other things -- from RDF descriptions that use the Jena Assembler vocabulary. That vocabulary is available in ja-vocabulary.n3 as an RDFS schema with conventional prefix ja for the URI http://jena.hpl.hp.com/2005/11/Assembler#; the class JA is its Jena Java rendition.

The examples used in this document are extracted from the examples file examples.n3. The pieces of RDF/OWL schema are extracted from the ja-vocabulary file and can be viewed as N3 or in a condensed notation of the form:

class ClassName [subClassOf SuperClasses]
  domainOf PropertyName [withRange RangeClasses] [Cardinality] ...

The property names selected are those which are the "declared properties" (as per Jena's listDeclaredProperties method) of the class. Only the most specialised superclasses and rangeclasses are shown, so (for example) rdf:Resource typically won't appear.

overview

An Assembler specification is a Resource in some RDF Model. The properties of that Resource describe what kind of object is to be assembled and what its components are: for example, an InfModel is constructed by specifying a base model and a reasoner. The specifications for the components are themselves Assembler specifications given by other Resources in the same Model.For example, to specify a memory model with data loaded from a file:

eg:opening-example a ja:MemoryModel 
    ; ja:content [ja:externalContent <file:////home/kers/projects/jena2/doc/assembler/Data/example.n3>] 
    . 

The rdf:type of eg:model specifies that the constructed Model is to be a Jena memory-based model. The ja:content property specifies that the model is to be loaded with the content of the resource file:Data/example.n3. The content handler guesses from the ".n3" suffix that this file is to be read using the Jena N3 reader.

Unless otherwise specified by an application, Assembler specifications are interpreted after completion by

  1. including the JA schema,
  2. including (recursively) the objects of any owl:imports and ja:imports statements, and
  3. doing (limited) RDFS inference.
(The supplied model is not modified.) In the example above, eg:model has to be given an explicit type, but the externalContent bnode is implicitly typed by the domain of ja:externalContent. In this document, we will usually leave out inferrable types.

We can construct our example model from the specification like this (you may need to tweak the filename to make this work in your environment):

Model spec = FileManager.get().loadModel( "examples.n3" );
Resource root = spec.createResource( spec.expandPrefix( "eg:opening-example" ) );
Model m = Assembler.general.openModel( root );

The model is constructed from the "root resource", eg:opening-example in our example. general knows how to create all the kinds of objects -- not just Models -- that we describe in the next sections.

specifications common to all models

Assembler specifications can describe many kinds of models: memory, inference, database, ontology, and file-backed. All of these model specifications share a set of base properties for attaching content, prefix mappings, and reification modes.

∇ show as N3
class ja:Loadable subClassOf ja:Object
domainOf ja:initialContent withRange ja:Content
domainOf ja:content withRange ja:Content
∇ show as condensed
ja:Loadable a rdfs:Class
; rdfs:subClassOf ja:Object
.
ja:initialContent a rdf:Property
; rdfs:domain ja:Loadable
; rdfs:range ja:Content
.
ja:content a rdf:Property
; rdfs:domain ja:Loadable
; rdfs:range ja:Content
.
∇ show as N3
class ja:Model subClassOf ja:ContentItem ja:Loadable
domainOf ja:prefixMapping withRange ja:PrefixMapping
domainOf ja:reificationMode withRange ja:ReificationMode
∇ show as condensed
ja:Model a rdfs:Class
; rdfs:subClassOf ja:ContentItem
; rdfs:subClassOf ja:Loadable
.
ja:prefixMapping a rdf:Property
; rdfs:domain ja:Model
; rdfs:range ja:PrefixMapping
.
ja:reificationMode a rdf:Property
; rdfs:domain ja:Model
; rdfs:range ja:ReificationMode
.

All of a model's ja:content property values are interpreted as specifying Content objects and a single composite Content object is constructed and used to initialise the model. See Content for the description of Content specifications. For example:

eg:sharedContent
    ja:externalContent <http://somewhere/RDF/ont.owl> 
    . 
eg:common-example a ja:MemoryModel 
    ; ja:content eg:sharedContent 
    ; ja:content [ja:externalContent <file:////home/kers/projects/jena2/doc/assembler/Data/B.rdf>] 
    ; ja:content [ja:externalContent <file:////home/kers/projects/jena2/doc/assembler/Data/A.rdf>] 
    . 

The model constructed for eg:A will be loaded with the contents of Data/A.n3, Data/B.rdf, and http://somewhere/RDF/ont.owl. If the model supports transactions, then the content is loaded inside a transaction; if the load fails, the transaction is aborted, and a TransactionAbortedException thrown. If the content has any prefix mappings, then they are also added to the model.

All of a model's ja:prefixMapping, ja:prefix, and ja:namespace properties are interpreted as specifying a PrefixMapping object and a single composite PrefixMapping is constructed and used to set the prefixes of the model. See PrefixMapping for the description of Content specifications.

A model may have a single ja:reificationMode property whose value must be one of the constants ja:standard, ja:convenient, or ja:minimal. The model's reification mode is set accordingly, if possible.

content

A Content specification describes content that can be used to fill models. Content can be external (files and URLs) or literal (strings in the specification) or quotations (referring to RDF which is part of the specification).
∇ show as N3
class ja:Content subClassOf ja:HasFileManager
∇ show as condensed
ja:Content a rdfs:Class
; rdfs:subClassOf ja:HasFileManager
.
∇ show as N3
class ja:HasFileManager subClassOf ja:Object
domainOf ja:fileManager withRange ja:FileManager
∇ show as condensed
ja:HasFileManager a rdfs:Class
; rdfs:subClassOf ja:Object
.
ja:fileManager a rdf:Property
; rdfs:domain ja:HasFileManager
; rdfs:range ja:FileManager
.

A ja:Content specification may have zero or more ja:externalContent property values. These are URI resources naming an external (file or http etc) RDF object. The constructed Content object contains the union of the values of all such resources. For example:

eg:external-content-example
    ja:externalContent <file:////home/kers/projects/jena2/doc/assembler/Data/C.owl>,
        <http://jena.hpl.hp.com/some-jena-data.rdf> 
    . 

The external content is located using a FileManager. If the Content resource has a ja:fileManager property, then the FileManager described by that resource is used. Otherwise, if the ContentAssembler assembling this specification was constructed with a FileManager argument, that FileManager is used. Otherwise, the default FileManager, FileManager.get(), is used.

The string literal value of the any ja:literalContent properties is interpreted as RDF in an appropriate language. The constructed Content object contains that RDF. The language is either specified by an explicit ja:contentEncoding property value, or guessed from the content of the string. The only encodings permitted are "N3" and "RDF/XML". For example:

eg:literal-content-example
    ja:literalContent "_:it dc:title 'Interesting Times'" 
    . 

The literal content is wrapped so that prefix declarations for rdf, rdfs, owl, dc, and xsd apply before interpretation.

The property values of any ja:quotedContent properties should be resources. The subgraphs rooted at those resources (using the algorithm from ResourceUtils.reachableClosure()) are added to the content.

RDB models and Connections

The description of an RDB model requires its name and a description of the JDBC connection for the database the model is in. For example:

eg:database-example
    ja:connection eg:connection 
    ; ja:modelName "Thunderbird3" 
    . 
eg:connection
    ja:dbType "MySQL" 
    ; ja:dbURL <jdbc:mysql://localhost/test> 
    ; ja:dbUser "cjd" 
    . 
∇ show as N3
class ja:RDBModel subClassOf ja:Connectable ja:NamedModel
∇ show as condensed
ja:RDBModel a rdfs:Class
; rdfs:subClassOf ja:Connectable
; rdfs:subClassOf [owl:onProperty ja:connection; owl:cardinality 1]
; rdfs:subClassOf ja:NamedModel
.
∇ show as N3
class ja:Connectable subClassOf ja:Object
domainOf ja:connection withRange ja:Connection
∇ show as condensed
ja:Connectable a rdfs:Class
; rdfs:subClassOf ja:Object
.
ja:connection a rdf:Property
; rdfs:domain ja:Connectable
; rdfs:range ja:Connection
.
∇ show as N3
class ja:NamedModel subClassOf ja:Model
domainOf ja:modelName cardinality 1
∇ show as condensed
ja:NamedModel a rdfs:Class
; rdfs:subClassOf [owl:onProperty ja:modelName; owl:cardinality 1]
; rdfs:subClassOf ja:Model
.
ja:modelName a rdf:Property
; rdfs:domain ja:NamedModel
.

ja:RDBModel is a subclass of ja:NamedModel and shares the ja:ModelName property value naming the model within the database.

The mandatory unique property value of ja:connection specifies the connection to the database to be used.

The description of a connection requires the database name and type and the user name and password. If the username and password are not specified, Assembler.general will default them, normally to the values of the system properties jena.dbUser and jena.dbPassword.

∇ show as N3
class ja:Connection subClassOf ja:Object
domainOf ja:dbTypeProperty maxCardinality 1
domainOf ja:dbPasswordProperty maxCardinality 1
domainOf ja:dbType maxCardinality 1
domainOf ja:dbURL maxCardinality 1
domainOf ja:dbPassword maxCardinality 1
domainOf ja:dbURLProperty maxCardinality 1
domainOf ja:dbUserProperty maxCardinality 1
domainOf ja:dbClass maxCardinality 1
domainOf ja:dbClassProperty maxCardinality 1
domainOf ja:dbUser maxCardinality 1
∇ show as condensed
ja:Connection a rdfs:Class
; rdfs:subClassOf [owl:onProperty ja:dbURLProperty; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:dbPassword; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:dbType; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:dbURL; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:dbTypeProperty; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:dbUser; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:dbPasswordProperty; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:dbUserProperty; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:dbClassProperty; owl:maxCardinality 1]
; rdfs:subClassOf ja:Object
; rdfs:subClassOf [owl:onProperty ja:dbClass; owl:maxCardinality 1]
.
ja:dbTypeProperty a rdf:Property
; rdfs:domain ja:Connection
.
ja:dbPasswordProperty a rdf:Property
; rdfs:domain ja:Connection
.
ja:dbType a rdf:Property
; rdfs:domain ja:Connection
.
ja:dbURL a rdf:Property
; rdfs:domain ja:Connection
.
ja:dbPassword a rdf:Property
; rdfs:domain ja:Connection
.
ja:dbURLProperty a rdf:Property
; rdfs:domain ja:Connection
.
ja:dbUserProperty a rdf:Property
; rdfs:domain ja:Connection
.
ja:dbClass a rdf:Property
; rdfs:domain ja:Connection
.
ja:dbClassProperty a rdf:Property
; rdfs:domain ja:Connection
.
ja:dbUser a rdf:Property
; rdfs:domain ja:Connection
.

The ja:dbURL property value specifies the URL of the database to be connected to. If it is ommitted, the ja:dbURLProperty value is the name of a Java system property whose value is the URL of the database.

The ja:dbType property value specifies the type of the database as a string. If it is omitted, the ja:dbTypeProperty value is the name of a Java system property whose value is the database type.

The unique ja:dbUser property value is a string literal whose value is the name of the user connecting to the database. If it is omitted, the value of the ja:dbUserProperty is the name of a Java system property containing the user name.

The unique ja:dbPassword property value is the password of the user connecting to the database. If it is omitted, the value of the ja:dbPasswordProperty is the name of a Java system property whose value is the password.

file models

A FileModel specification builds a memory model that is backed by a file. By "backed", we mean that the model is loaded from that file and written back to the file when (if) it is closed. Furthermore, the model (weakly) supports transactions.

eg:fileModel-example-1
    ja:directory <file:///tmp> 
    ; ja:modelName "simple" 
    . 

Here, the model is read from (and written to) the file /tmp/simple. Directory names are given as resources (not literals) and of course file names are system dependant -- this is what one might see on a Unix system. If the directory name is to be shared by several different FileModels, it can be useful to give it a namespace prefix so that it can be changed in one place as necessary.

eg:fileModel-example-2
    ja:directory <file:////home/kers/projects/jena2/doc/assembler/FileModels> 
    ; ja:mapName ja:true 
    ; ja:modelName "http://somewhere.org/stuff.n3" 
    . 

Model names can be mapped to allow them to be URIs without the /s in URIs being taken as directory separators. Here, the base file name will be FileModels/http_C_S_Ssomewhere.org_Sstuff.n3. The encoding is not pretty, but is sufficient for simple URIs.

∇ show as N3
class ja:FileModel subClassOf ja:NamedModel
domainOf ja:fileEncoding maxCardinality 1
domainOf ja:directory maxCardinality 1
domainOf ja:mapName maxCardinality 1
∇ show as condensed
ja:FileModel a rdfs:Class
; rdfs:subClassOf [owl:onProperty ja:mapName; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:directory; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:fileEncoding; owl:maxCardinality 1]
; rdfs:subClassOf ja:NamedModel
.
ja:fileEncoding a rdf:Property
; rdfs:domain ja:FileModel
.
ja:directory a rdf:Property
; rdfs:domain ja:FileModel
.
ja:mapName a rdf:Property
; rdfs:domain ja:FileModel
.

The ja:directory property specifies the directory in which the model file is located. The ja:modelName property specifies the name of the file within that directory.

The optional unique property ja:fileEncoding has as its value a string which is the name of the encoding language of the model (ie one of RDF/XML or N3, etc). If it is omitted, the language is guessed from the suffix of the filename (as per FileUtils.guessLang()).

If the optional unique property ja:mapName has the value ja:true, then the name of the model is mapped by replacing any _, /, or : characters by the escape sequences __, _S, or _C. This translation (which is the same one done by FileGraphMaker for FileModelMaker) allows URIs to be used as model names without conflicting with the filesystems use of / characters.

inference models and reasoners

Inference models are specified by supplying a description of the reasoner that is used by the model and (optionally) a base model to reason over. For example:

eg:inference-example
    ja:baseModel [a ja:MemoryModel] 
    ; ja:reasoner [ja:reasonerURL <http://jena.hpl.hp.com/2003/RDFSExptRuleReasoner>] 
    . 

describes an inference model that uses RDFS reasoning. The reasonerURL property value is the URI used to identify the reasoner (it is the value of the Jena constant RDFSRuleReasonerFactory.URI). The base model is specified as a memory model; if it is left out, an empty memory model is used. Of course, you can specify a database model as a base model:

eg:database-example
    ja:connection eg:connection 
    ; ja:modelName "Thunderbird3" 
    . 
eg:connection
    ja:dbType "MySQL" 
    ; ja:dbURL <jdbc:mysql://localhost/test> 
    ; ja:dbUser "cjd" 
    . 
eg:db-inference-example
    ja:baseModel eg:database-example 
    ; ja:reasoner [ja:reasonerURL <http://jena.hpl.hp.com/2003/RDFSExptRuleReasoner>] 
    . 

The same reasoner as used as in the previous example, but now the base model is a database specified in the same way as our earlier example.

Because Jena's access to external reasoners goes through the same API as for its internal reasoners, you can access a DIG reasoner (such as Pellet running as a server) using an Assembler specification:

eg:external-inference-example
    ja:reasoner [<http://jena.hpl.hp.com/2003/JenaReasoner#extReasonerURL>
    <http://localhost:2004/> 
    ; ja:reasonerURL <http://jena.hpl.hp.com/2003/DIGReasoner>] 
    . 
If there's a DIG server running locally on port 2004, this specification will create a DIG inference model that uses it.

The internal rule reasoner can be supplied with rules written inside the specification, or outside from some resource (file or http: URL):

eg:rule-inference-example
    ja:reasoner [ja:rule "[r1: (?x my:P ?y) -> (?x rdf:type my:T)]"] 
    . 
This reasoner will infer a type declaration from a use of a property. (The prefix my will have to be known to the rule parser, of course.)

∇ show as N3
class ja:InfModel subClassOf ja:Model
domainOf ja:reasoner withRange ja:ReasonerFactory maxCardinality 1
domainOf ja:baseModel withRange ja:Model maxCardinality 1
∇ show as condensed
ja:InfModel a rdfs:Class
; rdfs:subClassOf [owl:onProperty ja:reasoner; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:baseModel; owl:maxCardinality 1]
; rdfs:subClassOf ja:Model
.
ja:reasoner a rdf:Property
; rdfs:domain ja:InfModel
; rdfs:range ja:ReasonerFactory
.
ja:baseModel a rdf:Property
; rdfs:domain ja:InfModel
; rdfs:range ja:Model
.
∇ show as N3
class ja:HasRules subClassOf ja:Object
domainOf ja:rule
domainOf ja:rulesFrom
domainOf ja:rules withRange ja:RuleSet
∇ show as condensed
ja:HasRules a rdfs:Class
; rdfs:subClassOf ja:Object
.
ja:rule a rdf:Property
; rdfs:domain ja:HasRules
.
ja:rulesFrom a rdf:Property
; rdfs:domain ja:HasRules
.
ja:rules a rdf:Property
; rdfs:domain ja:HasRules
; rdfs:range ja:RuleSet
.

An InfModel's ja:baseModel property value specifies the base model for the inference model; if omitted, an empty memory model is used.

An InfModel's ja:ReasonerFactory property value specifies the Reasoner for this inference model; if omitted, a GenericRuleReasoner is used.

A Reasoner's optional ja:schema property specifies a Model which contains the schema for the reasoner to be bound to. If omitted, no schema is used.

If the Reasoner is a GenericRuleReasoner, it may have any of the RuleSet properties ja:rules, ja:rulesFrom, or ja:rule. The rules of the implied RuleSet are added to the Reasoner.

ReasonerFactory

A ReasonerFactory can be specified by URL or by class name (but not both).

∇ show as N3
class ja:ReasonerFactory subClassOf ja:HasRules
domainOf ja:reasonerClass
domainOf ja:reasonerURL
domainOf ja:schema withRange ja:Model
∇ show as condensed
ja:ReasonerFactory a rdfs:Class
; rdfs:subClassOf [owl:onProperty ja:ReasonerURL; owl:maxCardinality 1]
; rdfs:subClassOf ja:HasRules
.
ja:reasonerClass a rdf:Property
; rdfs:domain ja:ReasonerFactory
.
ja:reasonerURL a rdf:Property
; rdfs:domain ja:ReasonerFactory
.
ja:schema a rdf:Property
; rdfs:domain ja:ReasonerFactory
; rdfs:range ja:Model
.

If the optional unique property ja:reasonerURL is specified, then its resource value is the URI of a reasoner in the Jena reasoner registry; the reasoner is the one with the given URI.

If the optional property ja:schema is specified, then the models specified by all the schema properties are unioned and any reasoner produced by the factory will have that union bound in as its schema (using the Reasoner::bindSchema() method).

If the optional unique property ja:reasonerClass is specified, its value names a class which implements ReasonerFactory. That class is loaded and an instance of it used as the factory.

The class may be named by the lexical form of a literal, or by a URI with the (fake) "java:" scheme.

If the class has a method theInstance, that method is called to supply the ReasonerFactory instance to use. Otherwise, a new instance of that class is constructed. Jena's reasoner factories come equipped with this method; for other factories, see the documentation.

rulesets

A RuleSet specification allows rules (for ReasonerFactories) to be specified inline, elsewhere in the specification model, or in an external resource.

∇ show as N3
class ja:RuleSet subClassOf ja:HasRules
∇ show as condensed
ja:RuleSet a rdfs:Class
; rdfs:subClassOf ja:HasRules
.

The optional repeatable property ja:rule has as its value a literal string which is the text of a Jena rule or rules. All those rules are added to the RuleSet.

The optional repeatable property ja:rulesFrom has as its value a resource whose URI identifies a file or other external entity that can be loaded as Jena rules. All those rules are added to the RuleSet.

The optional repeatable property ja:rules has as its value a resource which identifies another RuleSet in the specification model. All those rules from that RuleSet are added to this RuleSet.

ontology models

Ontology models can be specified in several ways. The simplest is to use the name of an OntModelSpec from the Java OntModelSpec class:

eg:simple-ont-example
    ja:ontModelSpec ja:OWL_DL_MEM_RULE_INF 
    . 

This constructs an OntModel with an empty base model and using the OWL_DL language and the full rule reasoner. All of the OntModelSpec constants in the Jena implementation are available in this way. A base model can be specified:

eg:base-ont-example
    ja:baseModel [a ja:MemoryModel 
    ; ja:content [ja:externalContent <http://jena.hpl.hp.com/some-jena-data.rdf>]] 
    . 

The OntModel has a base which is a memory model loaded with the contents of http://jena.hpl.hp.com/some-jena-data.rdf. Since the ontModelSpec was omitted, it defaults to OWL_MEM_RDFS_INF - the same default as ModelFactory.createOntologyModel().

∇ show as N3
class ja:OntModel subClassOf ja:UnionModel ja:InfModel
domainOf ja:ontModelSpec withRange ja:OntModelSpec
∇ show as condensed
ja:OntModel a rdfs:Class
; rdfs:subClassOf ja:UnionModel
; rdfs:subClassOf ja:InfModel
.
ja:ontModelSpec a rdf:Property
; rdfs:domain ja:OntModel
; rdfs:range ja:OntModelSpec
.
∇ show as N3
class ja:OntModelSpec subClassOf ja:Object
domainOf ja:importSource maxCardinality 1
domainOf ja:reasonerFactory withRange ja:ReasonerFactory maxCardinality 1
domainOf ja:documentManager maxCardinality 1
domainOf ja:ontLanguage maxCardinality 1
domainOf ja:likeBuiltinSpec
∇ show as condensed
ja:OntModelSpec a rdfs:Class
; rdfs:subClassOf [owl:onProperty ja:like; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:reasonerFactory; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:importSource; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:documentManager; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:ontLanguage; owl:maxCardinality 1]
; rdfs:subClassOf ja:Object
.
ja:importSource a rdf:Property
; rdfs:domain ja:OntModelSpec
.
ja:reasonerFactory a rdf:Property
; rdfs:domain ja:OntModelSpec
; rdfs:range ja:ReasonerFactory
.
ja:documentManager a rdf:Property
; rdfs:domain ja:OntModelSpec
.
ja:ontLanguage a rdf:Property
; rdfs:domain ja:OntModelSpec
.
ja:likeBuiltinSpec a rdf:Property
; rdfs:domain ja:OntModelSpec
.

OntModel is a subclass of InfModel, and the ja:baseModel property means the same thing.

The OntModelSpec property value is a resource, interpreted as an OntModelSpec description based on its name and the value of the appropriate properties:

Any unspecified properties have default values, normally taken from those of OntModelSpec.OWL_MEM_RDFS_INF. However, if the OntModelSpec resource is in the JA namespace, and its local name is the same as that of an OntModelSpec constant, then that constant is used as the default value.

document managers

An OntDocumentManager can be specified by a ja:DocumentManager specification which describes the OntDocumentManager's file manager and policy settings.

eg:mapper
    lm:mapping [lm:altName "file:etc/foo.n3" 
    ; lm:name "file:foo.n3"] 
    . 
eg:document-manager-example
    ja:fileManager [ja:locationMapper eg:mapper] 
    ; ja:meta [ dm:altURL <http://localhost/RDF/my-alt.rdf>] 
    . 

In this example, eg:document-manager-example is a ja:DocumentManager specification. It has its own FileManager specification, the object of the ja:fileManager property; that FileManager has a location mapper, eg:mapper, that maps a single filename.

The document manager also has an additional property to link it to document manager meta-data: the sub-model of the assembler specification reachable from eg:document-manager-example is passed to the document manager when it is created. For the meanings of the dm: properties, see the Jena ontology documentation and the ontology.rdf ontology.

∇ show as N3
class ja:DocumentManager subClassOf ja:HasFileManager
domainOf ja:policyPath maxCardinality 1
∇ show as condensed
ja:DocumentManager a rdfs:Class
; rdfs:subClassOf [owl:onProperty ja:policyPath; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:fileManager; owl:maxCardinality 1]
; rdfs:subClassOf [owl:onProperty ja:fileManager; owl:maxCardinality 1]
; rdfs:subClassOf ja:HasFileManager
.
ja:policyPath a rdf:Property
; rdfs:domain ja:DocumentManager
.

The ja:fileManager property value, if present, has as its object a ja:FileManager specification; the constructed document manager is given a new file manager constructed from that specification. If there is no ja:fileManager property, then the default FileManager is used.

The ja:policyPath property value, if present, should be a string which is a path to policy files as described in the Jena ontology documentation. If absent, the usual default path is applied.

If the sub-model of the assembler specification reachable from the DocumentManager resource contains any OntDocumentManager DOC_MGR_POLICY or ONTOLOGY_SPEC objects, they will be interpreted by the constructed document manager object.

∇ show as N3
class ja:FileManager subClassOf ja:Object
domainOf ja:locationMapper withRange ja:LocationMapper maxCardinality 1
∇ show as condensed
ja:FileManager a rdfs:Class
; rdfs:subClassOf [owl:onProperty ja:locationMapper; owl:maxCardinality 1]
; rdfs:subClassOf ja:Object
.
ja:locationMapper a rdf:Property
; rdfs:domain ja:FileManager
; rdfs:range ja:LocationMapper
.

A ja:FileManager object may have a ja:locationMapper property value which identifies the specification of a LocationMapper object initialising that file manager.

∇ show as N3
class ja:LocationMapper subClassOf ja:Object
domainOf lm:mapping maxCardinality 1
∇ show as condensed
ja:LocationMapper a rdfs:Class
; rdfs:subClassOf [owl:onProperty lm:mapping; owl:maxCardinality 1]
; rdfs:subClassOf ja:Object
.
lm:mapping a rdf:Property
; rdfs:domain ja:LocationMapper
.

A ja:LocationMapper object may have lm:mapping property values, describing the location mapping, as described in the FileManager documentation. (Note that the vocabulary for those items is in a different namespace than the JA properties and classes.)

union models

Union models can be constructed from any number of submodels and a single root model. The root model is the one written to when the union model is updated; the submodels are untouched.

∇ show as N3
class ja:UnionModel subClassOf ja:Model
domainOf ja:rootModel withRange ja:Model maxCardinality 1
domainOf ja:subModel withRange ja:Model
∇ show as condensed
ja:UnionModel a rdfs:Class
; rdfs:subClassOf [owl:onProperty ja:rootModel; owl:maxCardinality 1]
; rdfs:subClassOf ja:Model
.
ja:rootModel a rdf:Property
; rdfs:domain ja:UnionModel
; rdfs:range ja:Model
.
ja:subModel a rdf:Property
; rdfs:domain ja:UnionModel
; rdfs:range ja:Model
.

If the single ja:rootModel property is present, its value describes a model to use as the root model of the union. All updates to the union are directed to this root model. If no root model is supplied, the union is given an immutable, empty model as its root.

Any ja:subModel property values have objects describing the remaining sub-models of the union. The order of the sub-models in the union is undefined (which is why there's a special rootModel property).

prefix mappings

The PrefixMappings of a model may be set from PrefixMapping specifications.

∇ show as N3
class ja:PrefixMapping subClassOf ja:Object
domainOf ja:includes withRange ja:PrefixMapping
∇ show as condensed
ja:PrefixMapping a rdfs:Class
; rdfs:subClassOf ja:Object
.
ja:includes a rdf:Property
; rdfs:domain ja:PrefixMapping
; rdfs:range ja:PrefixMapping
.
∇ show as N3
class ja:SinglePrefixMapping subClassOf ja:PrefixMapping
domainOf ja:namespace cardinality 1
domainOf ja:prefix cardinality 1
∇ show as condensed
ja:SinglePrefixMapping a rdfs:Class
; rdfs:subClassOf [owl:onProperty ja:namespace; owl:cardinality 1]
; rdfs:subClassOf [owl:onProperty ja:prefix; owl:cardinality 1]
; rdfs:subClassOf ja:PrefixMapping
.
ja:namespace a rdf:Property
; rdfs:domain ja:SinglePrefixMapping
.
ja:prefix a rdf:Property
; rdfs:domain ja:SinglePrefixMapping
.

The ja:includes property allows a PrefixMapping to include the content of other specified PrefixMappings.

The ja:prefix and ja:namespace properties allow the construction of a single element of a prefix mapping by specifying the prefix and namespace of the mapping.

other Assembler directives

There are two more Assembler directives that can be used in an Assembler specification: the assembler and imports directives.

assembler

A specification may contain statements of the form:

someResource ja:assembler "some.Assembler.class.name"

When someResource is used as the type of a root object, the AssemblerGroup that processes the description will use an instance of the Java class named by the object of the statement. That class must implement the Assembler interface. See loading assembler classes for more details.

Similarly, statements of the form:

someResource ja:loadClass "some.class.name"
will cause the named class to be loaded (but not treated as assemblers).

imports

If a specification contains statements of the form:

anyResource owl:imports someURL
or, equivalently,
anyResource ja:imports someURL
then the specification is regarded as also containing the contents of the RDF at someURL. That RDF may in turn contain imports referring to other RDF.

limited RDFS inference

The Assembler engine uses limited RDFS inference to complete the model it is given, so that the spec-writer does not need to write excessive and redundant RDF. (It does not use the usual Jena reasoners because this limited once-off reasoning has been faster.) The inference steps are:

This is sufficient for closed-world assembling. Other parts of the JA schema -- eg, cardinality constraints -- are hard-coded into the individual assemblers.