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IdentifierGenerator.java
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IdentifierGenerator.java
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package cz.cvut.kbss.ontodriver.jena.util;
import cz.cvut.kbss.ontodriver.exception.IdentifierGenerationException;
import cz.cvut.kbss.ontodriver.jena.connector.StorageConnector;
import cz.cvut.kbss.ontodriver.util.IdentifierUtils;
import cz.cvut.kbss.ontodriver.util.Vocabulary;
import org.apache.jena.rdf.model.Property;
import org.apache.jena.rdf.model.RDFNode;
import org.apache.jena.rdf.model.ResourceFactory;
import java.net.URI;
public class IdentifierGenerator {
private static final int GENERATOR_THRESHOLD = 64;
private final StorageConnector storageConnector;
public IdentifierGenerator(StorageConnector storageConnector) {
this.storageConnector = storageConnector;
}
/**
* Generates a unique identifier based on the specified class URI.
*
* @param classUri Type URI, used as the identifier base
* @return Generated identifier
*/
public URI generateIdentifier(URI classUri) {
int i = 0;
boolean exists;
final Property property = ResourceFactory.createProperty(Vocabulary.RDF_TYPE);
final RDFNode type = ResourceFactory.createResource(classUri.toString());
URI result;
do {
result = IdentifierUtils.generateIdentifier(classUri);
exists = storageConnector.contains(ResourceFactory.createResource(result.toString()), property, type);
i++;
} while (exists && i < GENERATOR_THRESHOLD);
if (i >= GENERATOR_THRESHOLD) {
throw new IdentifierGenerationException(
"Failed to generate a unique identifier in " + GENERATOR_THRESHOLD + " attempts.");
}
return result;
}
}