private static List<LinkedHashMap<String, Object>> getFeaturesForClass(
GraphDatabaseService db, Node classNode) {
List<LinkedHashMap<String, Object>> patternIds = new ArrayList<>();
for (Path p :
db.traversalDescription()
.depthFirst()
.relationships(withName("HAS_CLASS"), Direction.INCOMING)
.evaluator(Evaluators.fromDepth(1))
.evaluator(Evaluators.toDepth(1))
.traverse(classNode)) {
LinkedHashMap<String, Object> featureMap = new LinkedHashMap<>();
if (p.relationships().iterator().hasNext()) {
featureMap.put("frequency", p.relationships().iterator().next().getProperty("matches"));
} else {
featureMap.put("frequency", 0);
}
featureMap.put("feature", ((Long) p.endNode().getId()).intValue());
patternIds.add(featureMap);
}
return patternIds;
}
public static Map<Long, Integer> getTermFrequencyMapForDocument(
GraphDatabaseService db, Long classId) {
Map<Long, Integer> termDocumentMatrix;
String cacheKey = "TERM_DOCUMENT_FREQUENCY_" + classId;
if (vectorSpaceModelCache.getIfPresent(cacheKey) == null) {
Node classNode = db.getNodeById(classId);
termDocumentMatrix = new HashMap<>();
IteratorUtil.asCollection(
db.traversalDescription()
.depthFirst()
.relationships(withName("HAS_CLASS"), Direction.INCOMING)
.evaluator(Evaluators.fromDepth(1))
.evaluator(Evaluators.toDepth(1))
.traverse(classNode))
.stream()
.forEach(
p ->
termDocumentMatrix.put(
p.endNode().getId(), (Integer) p.lastRelationship().getProperty("matches")));
vectorSpaceModelCache.put(cacheKey, termDocumentMatrix);
} else {
termDocumentMatrix = (Map<Long, Integer>) vectorSpaceModelCache.getIfPresent(cacheKey);
}
return termDocumentMatrix;
}
public static int getDocumentSizeForFeature(GraphDatabaseService db, Long id) {
int documentSize;
String cacheKey = "DOCUMENT_SIZE_FEATURE_" + id;
if (vectorSpaceModelCache.getIfPresent(cacheKey) == null) {
Node startNode = db.getNodeById(id);
Iterator<Node> classes =
db.traversalDescription()
.depthFirst()
.relationships(withName("HAS_CLASS"), Direction.OUTGOING)
.evaluator(Evaluators.fromDepth(1))
.evaluator(Evaluators.toDepth(1))
.traverse(startNode)
.nodes()
.iterator();
documentSize = IteratorUtil.count(classes);
vectorSpaceModelCache.put(cacheKey, documentSize);
} else {
documentSize = (Integer) vectorSpaceModelCache.getIfPresent(cacheKey);
}
return documentSize;
}
private TraversalDescription traversalDescription(GraphDatabaseService db) {
return db.traversalDescription()
.breadthFirst()
.uniqueness(NODE_GLOBAL)
.relationships(withName("FRIEND"))
.evaluator(
new Evaluator() {
@Override
public Evaluation evaluate(Path path) {
if (path.length() == 4) {
return Evaluation.INCLUDE_AND_PRUNE;
}
return Evaluation.EXCLUDE_AND_CONTINUE;
}
});
}