Note: this page is here for historical and sentimental reasons.
Find the updated documentation here.
Javadoc for the API may be found included in the release
Many requests have come in for the online javadoc to be updated - now at release 3.4.3
In order to use the API in your own applications, you should download the latest binary release and ensure that all of the jar files are in the application class path.
Note: the latest OWL API requires Java 6 or newer. It has been compiled and tested on Oracle JDK 7 - we have no reports on it not working on other versions of the JDK, so if you find it not working on any JRE 6 or newer, please let us know in the bug section.
If you want to check out the source code and build the binaries yourself, you can either use ANT (build file is in the antbuild folder) or Maven. Maven is the build system currently used for official builds, and it includes OSGI compatibility in the builds (experimental feature).
The central point of access is the OWLOntologyManager, which is used to load, create and access ontologies. The examples below show how to create an instance of this class and how to use it.
Code examples
- The Rough Guide to the OWL API, a tutorial presented at OWLED 2011, can be found here.
- Source code for The Rough Guide to the OWL API (includes most of the code available in the subsequent examples).
- DL Query Example presenting an example of how to query an ontology.
- Examples include:
- - How to load an ontology
- - How to save an ontology
- - How to obtain references to entities (classes, properties, individuals etc.)
- - How to work with data types and other data ranges
- - How to work with user defined data ranges (e.g. int > 10)
- - How to work with string, data values and language tags
- - How to create an empty ontology, add axioms and save
- - How to specify that an individual is an instance of a class
- - How to specify that two individuals are related to each other.
- - How to add an object property assertion (triple) to an ontology
- - How to delete entities (classes, properties and individuals) from an ontology
- - How to create restrictions and ''add them to classes'' as superclasses
- - How to create an ontology and add some rules
- - How to interact with a reasoner
- - How to collect the properties that are used in restrictions on a given class
- - How to work with annotations such as labels and comments
- - How to save inferred axioms into a new ontology, or back into an existing ontology
- - How two (or more) ontologies can be merged in a simple way
- - How to 'walk' over the asserted structure of an ontology.
- - How to use OWLOntologyIRIMappers to redirect loading and loading of imports.
- - How to extract a locality based module from an ontology.
Programming with the OWL API Tutorial
Note: most of the API has changed since this tutorial was written (2007). The theoretical basis is, however, the same. If you are new to OWL, start with this.
A set of tutorial slides are available below. Some simple examples that relate to the tutorial slides are provided. These illustrate parsing ontologies from concrete formats; rendering to concrete formats; manipulating ontologies and using inference services. If you check out the OWL API source code from the sourceforge website, the tutorial examples can be found in the tutorial directory.
Slides
Slides are available in PDF format:
Code examples
Simple Hierarchy
This example shows how we can calculate and display a basic ontology hierarchy. The example makes use of an OWLReasoner to calculate the class hierarchy, then navigates the structure obtained, printing out basic information for each of the classes.
The example either uses a StructuralReasoner, which returns information about the hierarchy based solely on the assertions that are made in the ontology.
Rendering example
This example shows the definition of a simple renderer. The renderer provided an HTML page describing the entities in the ontology.
Closure Axioms
This example illustrates manipulation of axioms in an ontology.
Debugging
This example illustrates the use of the debugger. The debugger identifies axioms causing inconsistencies in OWL ontologies.
Name Changes from OWL API 2 to OWL API 3
Version 3 of the OWL API is backward incompatible with version 2 of
the OWL API. The reason for this is that it was decided to align the
names of interfaces with the names used in the
OWL 2
Structural Specification. The main API interfaces and corresponding
name changes are shown in the table below. It should be noted that the
URI class has been replaces with the IRI class.
Additionally, package names have changed. In general, replace "owl" with
"owlapi" in client code to rename OWL API 2 package names to OWL API 3
package names. For example, org.semanticweb.owl.model has
become org.semanticweb.owlapi.model.
| OWL API 2 Interface | OWL API 3 Interface |
| AddAxiom | |
| AxiomType | |
| DataRangeType | DatarangeType |
| DefaultChangeBroadcastStrategy | |
| DescriptionType | ClassExpressionType |
| ImmutableOWLOntologyChangeException | |
| MissingImportEvent | |
| MissingImportListener | |
| NamespaceManager | PrefixManager |
| OWLAnnotation | |
| OWLAnnotationAxiom | |
| OWLAnnotationVisitor | |
| OWLAnnotationVisitorEx | |
| OWLAnonymousDescription | OWLAnonymousClassExpression |
| OWLAnonymousIndividual | |
| OWLAntiSymmetricObjectPropertyAxiom | OWLAsymmetricObjectPropertyAxiom |
| OWLAxiom | |
| OWLAxiomAnnotationAxiom | |
| OWLAxiomChange | |
| OWLAxiomVisitor | |
| OWLAxiomVisitorEx | |
| OWLBooleanDescription | OWLBooleanClassExpression |
| OWLCardinalityRestriction | |
| OWLClass | |
| OWLClassAssertionAxiom | |
| OWLClassAxiom | |
| OWLCommentAnnotation | Use an annotation with rdfs:comment as the property |
| OWLCompositeOntologyChange | |
| OWLConstant | OWLLiteral |
| OWLConstantAnnotation | |
| OWLDataAllRestriction | OWLDataAllValuesFrom |
| OWLDataCardinalityRestriction | |
| OWLDataComplementOf | |
| OWLDataExactCardinalityRestriction | OWLDataExactCardinality |
| OWLDataFactory | |
| OWLDataMaxCardinalityRestriction | OWLDataMaxCardinality |
| OWLDataMinCardinalityRestriction | OWLDataMinCardinality |
| OWLDataOneOf | |
| OWLDataProperty | |
| OWLDataPropertyAssertionAxiom | |
| OWLDataPropertyAxiom | |
| OWLDataPropertyCharacteristicAxiom | |
| OWLDataPropertyDomainAxiom | |
| OWLDataPropertyExpression | |
| OWLDataPropertyRangeAxiom | |
| OWLDataRange | |
| OWLDataRangeFacetRestriction | OWLFacetRestriction |
| OWLDataRangeRestriction | OWLDatatypeRestriction |
| OWLDataSomeRestriction | OWLDataSomeValiesFrom |
| OWLDataSubPropertyAxiom | OWLSubDataPropertyOfAxiom |
| OWLDataType | OWLDatatype |
| OWLDataValueRestriction | OWLDataHasValue |
| OWLDataVisitor | |
| OWLDataVisitorEx | |
| OWLDeclarationAxiom | |
| OWLDeprecatedClassAxiom | Deprecation on IRIs is done using a built in annotation |
| OWLDeprecatedDataPropertyAxiom | Deprecation on IRIs is done using a built in annotation |
| OWLDeprecatedObjectPropertyAxiom | Deprecation on IRIs is done using a built in annotation |
| OWLDescription | OWLClassExpression |
| OWLDescriptionVisitor | OWLClassExpressionVisitor |
| OWLDescriptionVisitorEx | OWLClassExpressionVisitorEx |
| OWLDifferentIndividualsAxiom | |
| OWLDisjointClassesAxiom | |
| OWLDisjointDataPropertiesAxiom | |
| OWLDisjointObjectPropertiesAxiom | |
| OWLDisjointUnionAxiom | |
| OWLEntity | |
| OWLEntityAnnotationAxiom | OWLAnnotationAssertionAxiom |
| OWLEntityVisitor | |
| OWLEntityVisitorEx | |
| OWLEquivalentClassesAxiom | |
| OWLEquivalentDataPropertiesAxiom | |
| OWLEquivalentObjectPropertiesAxiom | |
| OWLException | |
| OWLFunctionalDataPropertyAxiom | |
| OWLFunctionalObjectPropertyAxiom | |
| OWLImportsDeclaration | |
| OWLIndividual | OWLNamedIndividual |
| OWLIndividualAxiom | |
| OWLInverseFunctionalObjectPropertyAxiom | |
| OWLInverseObjectPropertiesAxiom | |
| OWLIrreflexiveObjectPropertyAxiom | |
| OWLLabelAnnotation | Use an annotation with rdfs:label as the property |
| OWLLogicalAxiom | |
| OWLMutableOntology | |
| OWLNamedObject | |
| OWLNamedObjectVisitor | |
| OWLNamedObjectVisitorEx | |
| OWLNaryBooleanDescription | OWLNaryBooleanClassExpression |
| OWLNaryClassAxiom | |
| OWLNaryIndividualAxiom | |
| OWLNaryPropertyAxiom | |
| OWLNegativeDataPropertyAssertionAxiom | |
| OWLNegativeObjectPropertyAssertionAxiom | |
| OWLObject | |
| OWLObjectAllRestriction | OWLObjectAllValuesFrom |
| OWLObjectAnnotation | |
| OWLObjectCardinalityRestriction | |
| OWLObjectComplementOf | |
| OWLObjectExactCardinalityRestriction | OWLObjectExactCardinality |
| OWLObjectIntersectionOf | |
| OWLObjectMaxCardinalityRestriction | OWLObjectMaxCardinality |
| OWLObjectMinCardinalityRestriction | OWLObjectMinCardinality |
| OWLObjectOneOf | |
| OWLObjectProperty | |
| OWLObjectPropertyAssertionAxiom | |
| OWLObjectPropertyAxiom | |
| OWLObjectPropertyChainSubPropertyAxiom | OWLSubPropertyChainOfAxiom |
| OWLObjectPropertyCharacteristicAxiom | |
| OWLObjectPropertyDomainAxiom | |
| OWLObjectPropertyExpression | |
| OWLObjectPropertyInverse | |
| OWLObjectPropertyRangeAxiom | |
| OWLObjectSelfRestriction | OWLObjectHasSelf |
| OWLObjectSomeRestriction | OWLObjectSomeValuesFrom |
| OWLObjectSubPropertyAxiom | OWLSubObjectPropertyOfAxiom |
| OWLObjectUnionOf | |
| OWLObjectValueRestriction | OWLObjectHasValue |
| OWLObjectVisitor | |
| OWLObjectVisitorEx | |
| OWLOntology | |
| OWLOntologyAnnotationAxiom | Ontology annotations are now stored directly in an ontology and not as axioms in an ontology |
| OWLOntologyChange | |
| OWLOntologyChangeBroadcastStrategy | |
| OWLOntologyChangeException | |
| OWLOntologyChangeListener | |
| OWLOntologyChangeVetoException | |
| OWLOntologyChangeVisitor | |
| OWLOntologyCreationException | |
| OWLOntologyFactory | |
| OWLOntologyFactoryNotFoundException | |
| OWLOntologyFormat | |
| OWLOntologyLoaderListener | |
| OWLOntologyManager | |
| OWLOntologyManagerProperties | |
| OWLOntologyResourceAccessException | |
| OWLOntologySetProvider | |
| OWLOntologyStorageException | |
| OWLOntologyStorer | |
| OWLOntologyStorerNotFoundException | |
| OWLOntologyURIMapper | OWLOntologyIRIMapper |
| OWLOntologyURIMappingNotFoundException | OWLOntologyIRIMappingNotFoundException |
| OWLProperty | |
| OWLPropertyAssertionAxiom | |
| OWLPropertyAxiom | |
| OWLPropertyDomainAxiom | |
| OWLPropertyExpression | |
| OWLPropertyExpressionVisitor | |
| OWLPropertyExpressionVisitorEx | |
| OWLPropertyRange | |
| OWLPropertyRangeAxiom | |
| OWLQuantifiedRestriction | |
| OWLReflexiveObjectPropertyAxiom | |
| OWLRestriction | |
| OWLRuntimeException | |
| OWLSameIndividualsAxiom | OWLSameIndividualAxiom |
| OWLSubClassAxiom | OWLSubClassOfAxiom |
| OWLSubPropertyAxiom | OWLSubPropertyOfAxiom |
| OWLSymmetricObjectPropertyAxiom | |
| OWLTransitiveObjectPropertyAxiom | |
| OWLTypedConstant | OWLTypedLiteral |
| OWLUnaryPropertyAxiom | |
| OWLUntypedConstant | OWLStringLiteral |
| OWLValueRestriction | OWLHasValueRestriction |
| RemoveAxiom | |
| SWRLAtom | |
| SWRLAtomConstantObject | SWRLLiteralArgument |
| SWRLAtomDObject | SWRLDArgument |
| SWRLAtomDVariable | SWRLVariable |
| SWRLAtomIObject | SWRLObjectArgument |
| SWRLAtomIVariable | SWRLVariable |
| SWRLAtomIndividualObject | SWRLIndividualArgument |
| SWRLAtomObject | SWRLArgument |
| SWRLAtomVariable | SWRLVariable |
| SWRLBinaryAtom | |
| SWRLBuiltInAtom | |
| SWRLClassAtom | |
| SWRLDataFactory | |
| SWRLDataRangeAtom | |
| SWRLDataValuedPropertyAtom | SWRLDataPropertyAtom |
| SWRLDifferentFromAtom | SWRLDifferentIndividualsAtom |
| SWRLObject | |
| SWRLObjectPropertyAtom | |
| SWRLObjectVisitor | |
| SWRLObjectVisitorEx | |
| SWRLRule | |
| SWRLSameAsAtom | SWRLSameIndividualAtom |
| SWRLUnaryAtom | |
| SetOntologyURI | SetOntologyID |
| SpecificOntologyChangeBroadcastStrategy | |
| MonitorableOWLReasoner | Set an OWLReasonerProgressMonitor in the reasoner configuration at reasoner creation time |
| MonitorableOWLReasonerAdapter | |
| NullReasoner | |
| NullReasonerFactory | |
| OWLClassReasoner | OWLReasoner |
| OWLConsistencyChecker | OWLReasoner |
| OWLInconsistentOntologyException | |
| OWLIndividualReasoner | OWLReasoner |
| OWLPropertyReasoner | OWLReasoner |
| OWLReasoner | |
| OWLReasonerAdapter | OWLReasoner |
| OWLReasonerBase | OWLReasoner |
| OWLReasonerException | |
| OWLReasonerFactory | |
| OWLReasonerManager | |
| OWLReasonerManagerEvent | |
| OWLReasonerManagerImpl | |
| OWLReasonerManagerListener | |
| OWLSatisfiabilityChecker | OWLReasoner |
| UndefinedEntityException | |
| UnsupportedReasonerOperationException |