org.apache.commons.collections.iterators
Class ArrayIterator<E>

java.lang.Object
  org.apache.commons.collections.iterators.ArrayIterator<E>

All Implemented Interfaces:

Iterator<E>, ResettableIterator<E>

Direct Known Subclasses:

ArrayListIterator

public class ArrayIterator<E>
extends Object
implements ResettableIterator<E>

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: 1.1.1.1 $ $Date: 2005/05/23 04:34:46 $

Author:

James Strachan, Mauricio S. Moura, Michael A. Smith, Neil O'Toole, Matt Hall, John Watkinson, 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.
E	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<E>

Returns:

true if there is a next element to return

next

public E next()

Returns the next element in the array.

Specified by:

next in interface Iterator<E>

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<E>

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<E>