com.google.common.collect
Interface PeekingIterator<E>

All Superinterfaces:

Iterator<E>

public interface PeekingIterator<E>
extends Iterator<E>

An iterator that supports a one-element lookahead while iterating.

Since:

2010.01.04 stable (imported from Google Collections Library)

Author:

Mick Killianey

Method Summary

E	next()
E	peek() Returns the next element in the iteration, without advancing the iteration.
void	remove()

Methods inherited from interface java.util.Iterator

hasNext

Method Detail

peek

E peek()

Returns the next element in the iteration, without advancing the iteration.

Calls to peek() should not change the state of the iteration, except that it may prevent removal of the most recent element via remove().

Throws:

NoSuchElementException - if the iteration has no more elements according to Iterator.hasNext()

next

E next()

The objects returned by consecutive calls to peek() then next() are guaranteed to be equal to each other.

Specified by:

next in interface Iterator<E>

remove

void remove()

Implementations may or may not support removal when a call to peek() has occurred since the most recent call to next().

Specified by:

remove in interface Iterator<E>

Throws:

IllegalStateException - if there has been a call to peek() since the most recent call to next() and this implementation does not support this sequence of calls (optional)