How to get count of nodes matching xpath query

[Aleshko, Oleg]

Hi!
Is there a way to get number of nodes for xpath query without iterating through 
returned collection?
When I try to use count xpath function I'm getting an exception saying that 
it's not supported.
This code works, but I feel that there must be  a better solution.
        final QueryManager queryManager = 
getObjectContentManager().getQueryManager();

        final Iterator objectIterator = 
getObjectContentManager().getObjectIterator(queryManager.createQuery(
                
queryManager.createFilter(NewsComponentType.class).addJCRExpression(
                        
"topicSet/collection-element/topic/collection-element/property/collection-element/@value='"
                                + productType + "'")));

        // returns wrong size in some cases, see NodeIteratorImpl#getSize
        // return (int) ((RangeIterator) objectIterator).getSize();
        return Iterators.size(objectIterator);