jpl:jpl_set_element/2

Set must be a JPL reference to an object which implements the java.util.Set interface.

On backtracking, Element is bound to a JPL representation of each element of Set. This is a utility predicate, defined thus:

jpl_set_element(S, E) :-
    jpl_call(S, iterator, [], I),
    jpl_iterator_element(I, E).