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

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

All Implemented Interfaces:

Iterator<E>, ListIterator<E>, ResettableIterator<E>, ResettableListIterator<E>

public class ObjectArrayListIterator<E>
extends ObjectArrayIterator<E>
implements ListIterator<E>, ResettableListIterator<E>

Implements a ListIterator over an array of objects.

This iterator does not support add(E) or ObjectArrayIterator.remove(), as the object array cannot be structurally modified. The set(E) method is supported however.

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

Since:

Commons Collections 3.0

Version:

$Revision: 1.1.1.1 $ $Date: 2005/05/23 04:34:58 $

Author:

Neil O'Toole, Stephen Colebourne, Matt Hall, John Watkinson, Phil Steitz

See Also:

ObjectArrayIterator, Iterator, ListIterator

Field Summary

protected int

lastItemIndex Holds the index of the last item returned by a call to next() or previous().

Fields inherited from class org.apache.commons.collections.iterators.ObjectArrayIterator

array, endIndex, index, startIndex

Constructor Summary

ObjectArrayListIterator()
Constructor for use with setArray.

ObjectArrayListIterator(E[] array)
Constructs an ObjectArrayListIterator that will iterate over the values in the specified array.

ObjectArrayListIterator(E[] array, int start)
Constructs an ObjectArrayListIterator that will iterate over the values in the specified array from a specific start index.

ObjectArrayListIterator(E[] array, int start, int end)
Construct an ObjectArrayListIterator that will iterate over a range of values in the specified array.

Method Summary

void	add(E obj) This iterator does not support modification of its backing array's size, and so will always throw an UnsupportedOperationException when this method is invoked.
boolean	hasPrevious() Returns true if there are previous elements to return from the array.
E	next() Gets the next element from the array.
int	nextIndex() Gets the next index to be retrieved.
E	previous() Gets the previous element from the array.
int	previousIndex() Gets the index of the item to be retrieved if previous() is called.
void	reset() Resets the iterator back to the start index.
void	set(E obj) Sets the element under the cursor.

Methods inherited from class org.apache.commons.collections.iterators.ObjectArrayIterator

getArray, getEndIndex, getStartIndex, hasNext, remove, setArray

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

lastItemIndex

protected int lastItemIndex

Holds the index of the last item returned by a call to next() or previous(). This is set to -1 if neither method has yet been invoked. lastItemIndex is used to to implement the set(E) method.

Constructor Detail

ObjectArrayListIterator

public ObjectArrayListIterator()

Constructor for use with setArray.

Using this constructor, the iterator is equivalent to an empty iterator until ObjectArrayIterator.setArray(E[]) is called to establish the array to iterate over.

ObjectArrayListIterator

public ObjectArrayListIterator(E[] array)

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

Parameters:

array - the array to iterate over

Throws:

NullPointerException - if array is null

ObjectArrayListIterator

public ObjectArrayListIterator(E[] array,
                               int start)

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

Parameters:

array - the array to iterate over

start - the index to start iterating at

Throws:

NullPointerException - if array is null

IndexOutOfBoundsException - if the start index is out of bounds

ObjectArrayListIterator

public ObjectArrayListIterator(E[] array,
                               int start,
                               int end)

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

Parameters:

array - the array to iterate over

start - the index to start iterating at

end - the index (exclusive) to finish iterating at

Throws:

IndexOutOfBoundsException - if the start or end index is out of bounds

IllegalArgumentException - if end index is before the start

NullPointerException - if array is null

Method Detail

hasPrevious

public boolean hasPrevious()

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

Specified by:

hasPrevious in interface ListIterator<E>

Returns:

true if there is a previous element to return

previous

public E previous()

Gets the previous element from the array.

Specified by:

previous in interface ListIterator<E>

Returns:

the previous element

Throws:

NoSuchElementException - if there is no previous element

next

public E next()

Gets the next element from the array.

Specified by:

next in interface Iterator<E>

Specified by:

next in interface ListIterator<E>

Overrides:

next in class ObjectArrayIterator<E>

Returns:

the next element

Throws:

NoSuchElementException - if there is no next element

nextIndex

public int nextIndex()

Gets the next index to be retrieved.

Specified by:

nextIndex in interface ListIterator<E>

Returns:

the index of the item to be retrieved next

previousIndex

public int previousIndex()

Gets the index of the item to be retrieved if previous() is called.

Specified by:

previousIndex in interface ListIterator<E>

Returns:

the index of the item to be retrieved next

add

public void add(E obj)

This iterator does not support modification of its backing array's size, and so will always throw an UnsupportedOperationException when this method is invoked.

Specified by:

add in interface ListIterator<E>

Parameters:

obj - the object to add

Throws:

UnsupportedOperationException - always thrown.

set

public void set(E obj)

Sets the element under the cursor.

This method sets the element that was returned by the last call to next() of previous().

Note: ListIterator implementations that support add() and remove() only allow set() to be called once per call to next() or previous (see the ListIterator javadoc for more details). Since this implementation does not support add() or remove(), set() may be called as often as desired.

Specified by:

set in interface ListIterator<E>

Parameters:

obj - the object to set into the array

Throws:

IllegalStateException - if next() has not yet been called.

ClassCastException - if the object type is unsuitable for the array

reset

public void reset()

Resets the iterator back to the start index.

Specified by:

reset in interface ResettableIterator<E>

Specified by:

reset in interface ResettableListIterator<E>

Overrides:

reset in class ObjectArrayIterator<E>