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JOPA 0.13.0 brings support for advanced literal-related features - access to lexical form of literal values and support for RDF simple literals (strings without langauge tag). Another change concerns updated treatment of named graphs. See the GitHub release for details.

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This is a maintenance release. Jena, OWLAPI and RDF4J have been upgraded to their latest versions (3.10.0, 5.1.10 and 2.5.0 respectively) and a minor bug related to getReference results treatment has been fixed.

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The new version of JOPA has jumped to another major - 0.12.0. The main reason is a change in the EntityManager API - the getReference method was added to the API and its support has been implemented. There is one minor difference between the implementation of JOPA and the standard JPA implementation - JOPA does not throw EntityNotFoundException when the corresponding instance is not found. Instead, it returns null to stay consistent with the entity retrieval find method.

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JOPA 0.11.0 has just been released. We are updating version minor since there are some changes in the API. The Query API now supports processing results using Java 8 streams. Some bugs/issues have been fixed. In addition, some deprecated constants and classes were finally removed.

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JOPA 0.10.8 has just been released. The main added feature of this release is support for plural annotation properties. Besides that, several minor fixes have been fixed.

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JOPA 0.10.7 has just been released. We have added support for the Java 8 Date/Time API, so now entities can use, for example, LocalDate, LocalDateTime, or Instant as mapped entity attribute types.

Besides that, a bug which caused issues with caching instances of classes overriding equals/hashCode has been fixed.

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This is a maintenance release, which fixes several bugs. Also, VariableResult used by SparqlResultMapping now supports unbound variables, so that it can be used with OPTIONAL patterns.

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The new release of JOPA brings, besides code improvements and fixes also modified exception structure, so that all JOPA exceptions are now subclasses of OWLPersistenceException.

In addition, thanks to the newly defined aop.xml file, load time weaving can be used on projects using JOPA, allowing finally to switch to Java 9/10. More on this on the project wiki.

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This release fixes a critical NPX bug caused by inherited indirect collections not being removed when an entity was detached from the persistence context.

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The latest release of JOPA fixes an issue in SPARQL query parser, which problems with property paths used together with variables.

In addition, it brings support of setting the in-memory store used by the Jena and RDF4J OntoDriver at runtime. This means that the application is able to set a different in-memory store than the one it was initially connected to. This may be useful when the application sets up a memory store and populates it with some predefined data and then wants to access it from JOPA.

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The latest release of JOPA contains several bug fixes and improvements in the Jena driver. The most notable change is the support for reloading file-based storage in OntoDriver. This allows the application to reload data which might have been changed externally.

The reload is supported by the ReloadableDataSource, which can be unwrapped from an EntityManagerFactory. The following example shows this:

final EntityManagerFactory emf = // initialization of the Persistence
// Do some stuff
emf.unwrap(ReloadableDataSource.class).reload();

Note that the reloading happens outside any running transactions.

Asset Publisher

A new release of JOPA is out and it contains a long awaited feature - implementation of the Jena OntoDriver. It allows to access Jena-based storage (e.g. TDB) from JOPA, further extending capabilities of JOPA.

An example project using the Jena driver will be published in https://github.com/kbss-cvut/jopa-examples soon.

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This is a maintenance release. It fixes a bug in the clone building process, which caused errors when entities with circular references were encountered.

The next release will introduce a beta version of the Jena OntoDriver, which is currently under development.

Research Topics

  • Ontology-Based Data Integration
    • Unified Foundational Ontology
    • Ontology Engineering 
    • Spatial and Temporal Ontologies
  • Semantic Web
    • Semantic Web Stack RDF(S), OWL (2), SPARQL,
    • Expressive Queries to Semantic Web Ontologies, SPARQL-DL,
    • Annotated Information Search
  • Semantic Information Systems
    • Enterprise Java,
    • OO programming,
    • UML,
    • Web & mobile technologies, 
  • Linked Data & Open Data
    • Data Quality
    • Semantic Data Description

Blogs Aggregator

JOPA 0.13.0

JOPA 0.13.0 brings support for advanced literal-related features - access to lexical form of literal values and support for RDF simple literals (strings without langauge tag). Another change...

JOPA 0.12.1

This is a maintenance release. Jena, OWLAPI and RDF4J have been upgraded to their latest versions (3.10.0, 5.1.10 and 2.5.0 respectively) and a minor bug related to getReference results...

JOPA 0.12.0

The new version of JOPA has jumped to another major - 0.12.0. The main reason is a change in the EntityManager API - the getReference method was added to the API and its support has been...

JOPA 0.11.0

JOPA 0.11.0 has just been released. We are updating version minor since there are some changes in the API. The Query API now supports processing results using Java 8 streams. Some...

Semantic Government Vocabulary Paper Accepted

Our vision of a semantic vocabulary for sharing and discovery of government data assets has been accepted to JWS, see https://ssrn.com/abstract=3303148

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