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
  Version:
    $Id: ZippingIterator.java 1682196 2015-05-28 09:58:09Z tn $

- - ### 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

    Methods
    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`

- - ### 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

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