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

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

All Implemented Interfaces:
  Iterator, ResettableIterator

Direct Known Subclasses:
  ArrayListIterator

public class ArrayIterator
extends Object
implements ResettableIterator

Implements an `Iterator` over any array.

The array can be either an array of object or of primitives. If you know that you have an object array, the `ObjectArrayIterator` class is a better choice, as it will perform better.

The iterator implements a `reset()` method, allowing the reset of the iterator back to the start if required.

Since:
  Commons Collections 1.0
Version:
  $Revision: 1.11 $ $Date: 2004/02/18 00:59:50 $
Author:
  James Strachan, Mauricio S. Moura, Michael A. Smith, Neil O'Toole, Stephen Colebourne

Field Summary
`protected Object` `array` The array to iterate over
`protected int` `endIndex` The end index to loop to
`protected int` `index` The current iterator index
`protected int` `startIndex` The start index to loop from

Constructor Summary
`ArrayIterator()` Constructor for use with `setArray`.
`ArrayIterator(Object array)` Constructs an ArrayIterator that will iterate over the values in the specified array.
`ArrayIterator(Object array, int startIndex)` Constructs an ArrayIterator that will iterate over the values in the specified array from a specific start index.
`ArrayIterator(Object array, int startIndex, int endIndex)` Construct an ArrayIterator that will iterate over a range of values in the specified array.

Method Summary
`protected void` `checkBound(int bound, String type)` Checks whether the index is valid or not.
`Object` `getArray()` Gets the array that this iterator is iterating over.
`boolean` `hasNext()` Returns true if there are more elements to return from the array.
`Object` `next()` Returns the next element in the array.
`void` `remove()` Throws `UnsupportedOperationException`.
`void` `reset()` Resets the iterator back to the start index.
`void` `setArray(Object array)` Sets the array that the ArrayIterator should iterate over.

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

Field Detail

### array

    protected Object array

  The array to iterate over

### startIndex

    protected int startIndex

  The start index to loop from

### endIndex

    protected int endIndex

  The end index to loop to

### index

    protected int index

  The current iterator index

Constructor Detail

### ArrayIterator

    public ArrayIterator()

  Constructor for use with `setArray`.

  Using this constructor, the iterator is equivalent to an empty iterator until `setArray(Object)` is called to establish the array to iterate over.

### ArrayIterator

    public ArrayIterator(Object array)

  Constructs an ArrayIterator that will iterate over the values in the specified array.

Parameters:
  `array` - the array to iterate over.
Throws:
  `IllegalArgumentException` - if `array` is not an array.
  `NullPointerException` - if `array` is `null`

### ArrayIterator

    public ArrayIterator(Object array,
                         int startIndex)

  Constructs an ArrayIterator that will iterate over the values in the specified array from a specific start index.

Parameters:
  `array` - the array to iterate over.
  `startIndex` - the index to start iterating at.
Throws:
  `IllegalArgumentException` - if `array` is not an array.
  `NullPointerException` - if `array` is `null`
  `IndexOutOfBoundsException` - if the index is invalid

### ArrayIterator

    public ArrayIterator(Object array,
                         int startIndex,
                         int endIndex)

  Construct an ArrayIterator that will iterate over a range of values in the specified array.

Parameters:
  `array` - the array to iterate over.
  `startIndex` - the index to start iterating at.
  `endIndex` - the index to finish iterating at.
Throws:
  `IllegalArgumentException` - if `array` is not an array.
  `NullPointerException` - if `array` is `null`
  `IndexOutOfBoundsException` - if either index is invalid

Method Detail

### checkBound

    protected void checkBound(int bound,
                              String type)

  Checks whether the index is valid or not.

  Parameters:
    `bound` - the index to check
    `type` - the index type (for error messages)
  Throws:
    `IndexOutOfBoundsException` - if the index is invalid

### hasNext

    public boolean hasNext()

  Returns true if there are more elements to return from the array.

  Specified by:
    `hasNext` in interface `Iterator`
  Returns:
    true if there is a next element to return

### next

    public Object next()

  Returns the next element in the array.

  Specified by:
    `next` in interface `Iterator`
  Returns:
    the next element in the array
  Throws:
    `NoSuchElementException` - if all the elements in the array have already been returned

### remove

    public void remove()

  Throws `UnsupportedOperationException`.

  Specified by:
    `remove` in interface `Iterator`
  Throws:
    `UnsupportedOperationException` - always

### getArray

    public Object getArray()

  Gets the array that this iterator is iterating over.

  Returns:
    the array this iterator iterates over, or `null` if the no-arg constructor was used and `setArray(Object)` has never been called with a valid array.

### setArray

    public void setArray(Object array)

  Sets the array that the ArrayIterator should iterate over.

  If an array has previously been set (using the single-arg constructor or this method) then that array is discarded in favour of this one. Iteration is restarted at the start of the new array. Although this can be used to reset iteration, the `reset()` method is a more effective choice.

  Parameters:
    `array` - the array that the iterator should iterate over.
  Throws:
    `IllegalArgumentException` - if `array` is not an array.
    `NullPointerException` - if `array` is `null`

### reset

    public void reset()

  Resets the iterator back to the start index.

  Specified by:
    `reset` in interface `ResettableIterator`

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