## org.apache.commons.collections.iterators
Class LoopingIterator

    java.lang.Object
      org.apache.commons.collections.iterators.LoopingIterator

All Implemented Interfaces:
  Iterator, ResettableIterator

public class LoopingIterator
extends Object
implements ResettableIterator

An Iterator that restarts when it reaches the end.

The iterator will loop continuously around the provided elements, unless there are no elements in the collection to begin with, or all the elements have been `removed`.

Concurrent modifications are not directly supported, and for most collection implementations will throw a ConcurrentModificationException.

Since:
  Commons Collections 3.0
Version:
  $Revision: 1.9 $ $Date: 2004/02/18 00:59:50 $
Author:
  Jonathan Carlson, Stephen Colebourne

Constructor Summary
`LoopingIterator(Collection coll)` Constructor that wraps a collection.

Method Summary
`boolean` `hasNext()` Has the iterator any more elements.
`Object` `next()` Returns the next object in the collection.
`void` `remove()` Removes the previously retrieved item from the underlying collection.
`void` `reset()` Resets the iterator back to the start of the collection.
`int` `size()` Gets the size of the collection underlying the iterator.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### LoopingIterator

    public LoopingIterator(Collection coll)

  Constructor that wraps a collection.

  There is no way to reset an Iterator instance without recreating it from the original source, so the Collection must be passed in.

Parameters:
  `coll` - the collection to wrap
Throws:
  `NullPointerException` - if the collection is null

Method Detail

### hasNext

    public boolean hasNext()

  Has the iterator any more elements.

  Returns false only if the collection originally had zero elements, or all the elements have been `removed`.

  Specified by:
    `hasNext` in interface `Iterator`
  Returns:
    `true` if there are more elements

### next

    public Object next()

  Returns the next object in the collection.

  If at the end of the collection, return the first element.

  Specified by:
    `next` in interface `Iterator`
  Throws:
    `NoSuchElementException` - if there are no elements at all. Use `hasNext()` to avoid this error.

### remove

    public void remove()

  Removes the previously retrieved item from the underlying collection.

  This feature is only supported if the underlying collection's `iterator` method returns an implementation that supports it.

  This method can only be called after at least one `next()` method call. After a removal, the remove method may not be called again until another next has been performed. If the `reset()` is called, then remove may not be called until `next()` is called again.

  Specified by:
    `remove` in interface `Iterator`

### reset

    public void reset()

  Resets the iterator back to the start of the collection.

  Specified by:
    `reset` in interface `ResettableIterator`

### size

    public int size()

  Gets the size of the collection underlying the iterator.

  Returns:
    the current collection size

Copyright © 2001-2005 Apache Software Foundation. All Rights Reserved.