* There is no chance that (2) could be null, as it was previously controlled by the JobManager
* through the canEnhance() method and the computeEnhancement is always called iff the former
* returns true.
*/
session.addOntology(new GraphSource(signaturesGraph));
session.addOntology(new GraphSource(metadataGraph));
} catch (UnmodifiableOntologyCollectorException e1) {
throw new EngineException("Cannot add enhancement graph to OntoNet session for refactoring", e1);
}
try {