/guava/android/guava/src/com/google/common/graph/Traverser.java
order.insertInto ( horizon, successors ) ;
protected N computeNext() { do { N next = visitNext(horizon); if (next != null) { Iterator<? extends N> successors = successorFunction.successors(next).iterator(); if (successors.hasNext()) { <extra_id_0> } return next; } } while (!horizon.isEmpty()); return endOfData(); }