private <X extends Element> Iterator<X> iteratorList(final Iterator<X> iterator) {
final List<X> list = new ArrayList<>();
while (iterator.hasNext()) {
final X e = iterator.next();
if (HasContainer.testAll(e, this.hasContainers)) list.add(e);
}
return list.iterator();
}
/**
* Gets an iterator over those vertices/edges that have the specific IDs wanted, or those that
* have indexed properties with the wanted values, or failing that by just getting all of the
* vertices or edges.
*
* @param getElementsByIds Function that will return an iterator over all the vertices/edges in
* the graph that have the specific IDs
* @param getElementsByIndex Function that returns a stream of all the vertices/edges in the graph
* that have an indexed property with a specific value
* @param getAllElements Function that returns an iterator of all the vertices or all the edges
* (i.e. full scan)
* @return An iterator for all the vertices/edges for this step
*/
private <ElementType extends Element> Iterator<? extends ElementType> elements(
BiFunction<OrientGraph, Object[], Iterator<ElementType>> getElementsByIds,
TriFunction<OrientGraph, OIndex<Object>, Iterator<Object>, Stream<? extends ElementType>>
getElementsByIndex,
Function<OrientGraph, Iterator<ElementType>> getAllElements) {
final OrientGraph graph = getGraph();
if (this.ids != null && this.ids.length > 0) {
/** Got some element IDs, so just get the elements using those */
return this.iteratorList(getElementsByIds.apply(graph, this.ids));
} else {
/** Have no element IDs. See if there's an indexed property to use */
Set<OrientIndexQuery> indexQueryOptions = findIndex();
if (!indexQueryOptions.isEmpty()) {
List<ElementType> elements = new ArrayList<>();
indexQueryOptions.forEach(
indexQuery -> {
OLogManager.instance().debug(this, "using " + indexQuery);
Stream<? extends ElementType> indexedElements =
getElementsByIndex.apply(graph, indexQuery.index, indexQuery.values);
elements.addAll(
indexedElements
.filter(element -> HasContainer.testAll(element, this.hasContainers))
.collect(Collectors.<ElementType>toList()));
});
return elements.iterator();
} else {
OLogManager.instance()
.warn(
this,
"scanning through all elements without using an index for Traversal "
+ getTraversal());
return this.iteratorList(getAllElements.apply(graph));
}
}
}