Package org.apache.commons.collections4.iterators

# Class ZippingIterator<E>

java.lang.Object
org.apache.commons.collections4.iterators.ZippingIterator<E>

Type Parameters:
  `E` - the type of elements returned by this iterator.

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
  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
  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 Details

  - ### 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

  - ### 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

- ## Method Details

  - ### 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