public class PeekingIterator<E> extends Object implements Iterator<E>
The decorator supports the removal operation, but an IllegalStateException
will be thrown if remove() is called directly after a call to
peek() or element().
| Constructor and Description |
|---|
PeekingIterator(Iterator<? extends E> iterator)
Constructor.
|
| Modifier and Type | Method and Description |
|---|---|
E |
element()
Returns the next element in iteration without advancing the underlying iterator.
|
boolean |
hasNext() |
E |
next() |
E |
peek()
Returns the next element in iteration without advancing the underlying iterator.
|
static <E> PeekingIterator<E> |
peekingIterator(Iterator<? extends E> iterator)
Decorates the specified iterator to support one-element lookahead.
|
void |
remove() |
public PeekingIterator(Iterator<? extends E> iterator)
iterator - the iterator to decoratepublic static <E> PeekingIterator<E> peekingIterator(Iterator<? extends E> iterator)
If the iterator is already a PeekingIterator it is returned directly.
E - the element typeiterator - the iterator to decorateIllegalArgumentException - if the iterator is nullpublic E peek()
Note: this method does not throw a NoSuchElementException if the iterator
is already exhausted. If you want such a behavior, use element() instead.
The rationale behind this is to follow the Queue interface
which uses the same terminology.
public E element()
NoSuchElementException - if the iterator is already exhausted according to hasNext()Copyright © 2001–2013 The Apache Software Foundation. All rights reserved.