Clerezza - Representation

This bundle provides for functionality to parse and serialize RDF Graphs

License

License

GroupId

GroupId

org.apache.clerezza
ArtifactId

ArtifactId

representation
Last Version

Last Version

2.0.0
Release Date

Release Date

Type

Type

bundle
Description

Description

Clerezza - Representation
This bundle provides for functionality to parse and serialize RDF Graphs
Project URL

Project URL

https://mvnrepository.com/artifact/org.apache.clerezza/representation
Project Organization

Project Organization

The Apache Software Foundation

Download representation

Dependencies

compile (7)

Group / Artifact Type Version
org.apache.clerezza : api jar 2.0.0
org.apache.clerezza : api-implementation jar 2.0.0
org.osgi : org.osgi.core jar 6.0.0
org.osgi : org.osgi.compendium jar 5.0.0
org.apache.felix : org.apache.felix.scr.annotations jar 1.12.0
org.apache.felix : org.apache.felix.scr.ds-annotations jar 1.2.10
org.slf4j : slf4j-simple jar 1.7.28

test (1)

Group / Artifact Type Version
junit : junit jar 4.12

Project Modules

There are no modules declared in this project.

Building

Build using Apache Maven with

mvn install

FAQ

Some more advanced questions focused on showing the differences to other proposed APIs.

Can I add RdfTerms from one implementation to another?

Yes, any compliant implementation of BlankNode, Iri or Literal as well as Triple can be added to any implemenation of Graph, as long the Graph supports adding triples. Implementation may not require the nodes to be of a particular implementation of having been created with a specific factory.

How does it work?

Implementation might need to map instances of BlankNode to their internal implementation. This should be done in a way that when there is no more reference to the BlankNode object (i.e. when the object can be garbage collected) the mapping to the internal implementation is removed from memory to. This can be achieved by using a java.util.WeakHashMap

Do I get back the same object that I added?

For instances of Iri or Literals you get back an object that result equal to the originally added object, i.e. an object with the same HashCode and of which the equals method return true when compared with the originally added object. Ther is no guarantee that the same instance will be returned. For instances of BlankNode the above in only guaranteed as long as the original object is referenced. When the original object becomes eligible for garbage collection the implementation may start returning a different (an not equal) object. In practice this means BlankNode objects cannot safely be serialized (using Java serialization) or passed around via RMI.

Can an implementation remove redundant information from a Graph?

Yes, as long as this doesn't affect any BlankNode instance that is currently reachable (i.e. the Java object is in memory and is not eligible for garbage collection).

For example given the non-lean graph:

ex:a ex:p _:x .
_:y ex:p _:x .

As long as there is no BlankNode instance referencing _:y the implementation can reduce the graph to:

ex:a ex:p _:x .

removing the redundancy. If however there is a reachable BlankNode instance for _:y the implementation must not remove the redundancy as the code which has access to the object can go on adding a triple:

_:y ex:p2 ex:b .

Thus creating a graph that doesn't contain any internal redundancy, namely:

ex:a ex:p _:x .
_:y ex:p _:x .
_:y ex:p2 ex:b .
org.apache.clerezza

The Apache Software Foundation

Versions

Version
2.0.0