org.apache.commons.collections4.iterators

Class ZippingIterator<E>

java.lang.Object

org.apache.commons.collections4.iterators.ZippingIterator<E>

All Implemented Interfaces:

Iterator<E>

public class ZippingIterator<E>
extends Object
implements Iterator<E>

Provides an interleaved iteration over the elements contained in a collection of Iterators.

Given two Iterator instances A and B, the next() method on this iterator will switch between A.next() and B.next() until both iterators are exhausted.

Since:

4.1

Constructor Summary

Constructors

Constructor and Description
ZippingIterator(Iterator<? extends E>... iterators) Constructs a new ZippingIterator that will provide interleaved iteration of the specified iterators.
ZippingIterator(Iterator<? extends E> a, Iterator<? extends E> b) Constructs a new ZippingIterator that will provide interleaved iteration over the two given iterators.
ZippingIterator(Iterator<? extends E> a, Iterator<? extends E> b, Iterator<? extends E> c) Constructs a new ZippingIterator that will provide interleaved iteration over the three given iterators.

Method Summary

Modifier and Type	Method and Description
boolean	hasNext() Returns true if any child iterator has remaining elements.
E	next() Returns the next element from a child iterator.
void	remove() Removes the last returned element from the child iterator that produced it.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Detail

ZippingIterator

public ZippingIterator(Iterator<? extends E> a,
                       Iterator<? extends E> b)

Constructs a new ZippingIterator that will provide interleaved iteration over the two given iterators.

Parameters:

a - the first child iterator

b - the second child iterator

Throws:

NullPointerException - if either iterator is null

ZippingIterator

public ZippingIterator(Iterator<? extends E> a,
                       Iterator<? extends E> b,
                       Iterator<? extends E> c)

Constructs a new ZippingIterator that will provide interleaved iteration over the three given iterators.

Parameters:

a - the first child iterator

b - the second child iterator

c - the third child iterator

Throws:

NullPointerException - if either iterator is null

ZippingIterator

public ZippingIterator(Iterator<? extends E>... iterators)

Constructs a new ZippingIterator that will provide interleaved iteration of the specified iterators.

Parameters:

iterators - the array of iterators

Throws:

NullPointerException - if any iterator is null

Method Detail

hasNext

public boolean hasNext()

Returns true if any child iterator has remaining elements.

Specified by:

hasNext in interface Iterator<E>

Returns:

true if this iterator has remaining elements

next

public E next()
       throws NoSuchElementException

Returns the next element from a child iterator.

Specified by:

next in interface Iterator<E>

Returns:

the next interleaved element

Throws:

NoSuchElementException - if no child iterator has any more elements

remove

public void remove()

Removes the last returned element from the child iterator that produced it.

Specified by:

remove in interface Iterator<E>

Throws:

IllegalStateException - if there is no last returned element, or if the last returned element has already been removed