@Override
public Iterator<TitanRelation> execute(final VertexCentricQuery query) {
if (query.getVertex().isNew()) return Iterators.emptyIterator();
final EdgeSerializer edgeSerializer = graph.getEdgeSerializer();
FittedSliceQuery sq = edgeSerializer.getQuery(query);
final boolean fittedQuery = sq.isFitted();
final InternalVertex v = query.getVertex();
final boolean needsFiltering = !sq.isFitted() || !deletedRelations.isEmpty();
if (needsFiltering && sq.hasLimit())
sq = new FittedSliceQuery(sq, QueryUtil.updateLimit(sq.getLimit(), 1.1));
Iterable<TitanRelation> result = null;
double limitMultiplier = 1.0;
int previousDiskSize = 0;
boolean finished;
do {
finished = true;
Iterable<Entry> iter = null;
if (v instanceof CacheVertex) {
CacheVertex cv = (CacheVertex) v;
iter =
((CacheVertex) v)
.loadRelations(
sq,
new Retriever<SliceQuery, List<Entry>>() {
@Override
public List<Entry> get(SliceQuery query) {
return graph.edgeQuery(v.getID(), query, txHandle);
}
});
} else {
iter = graph.edgeQuery(v.getID(), sq, txHandle);
}
result =
Iterables.transform(
iter,
new Function<Entry, TitanRelation>() {
@Nullable
@Override
public TitanRelation apply(@Nullable Entry entry) {
return edgeSerializer.readRelation(v, entry);
}
});
if (needsFiltering) {
result =
Iterables.filter(
result,
new Predicate<TitanRelation>() {
@Override
public boolean apply(@Nullable TitanRelation relation) {
// Filter out updated and deleted relations
return (relation == ((InternalRelation) relation).it()
&& !deletedRelations.containsKey(Long.valueOf(relation.getID())))
&& (fittedQuery || query.matches(relation));
}
});
}
// Determine termination
if (needsFiltering && query.hasLimit()) {
if (!IterablesUtil.sizeLargerOrEqualThan(result, query.getLimit())) {
int currentDiskSize = IterablesUtil.size(iter);
if (currentDiskSize > previousDiskSize) {
finished = false;
previousDiskSize = currentDiskSize;
limitMultiplier *= 2;
sq =
new FittedSliceQuery(
sq, QueryUtil.updateLimit(sq.getLimit(), limitMultiplier));
}
}
}
} while (!finished);
return result.iterator();
}
private Entry serialize(StandardTitanGraph graph, TitanEdge e, int pos) {
EdgeSerializer edgeSerializer = graph.getEdgeSerializer();
InternalRelation r = (InternalRelation) e;
return edgeSerializer.writeRelation(r, pos, r.tx());
}