@GwtCompatible public interface PeekingIterator<E> extends java.util.Iterator<E>
See the Guava User Guide article on
PeekingIterator.
E peek()
Calls to peek() should not change the state of the iteration,
except that it may prevent removal of the most recent element via
remove().
java.util.NoSuchElementException - if the iteration has no more elements
according to Iterator.hasNext()E next()
The objects returned by consecutive calls to peek() then next() are guaranteed to be equal to each other.
next in interface java.util.Iterator<E>void remove()