org.apache.commons.collections.iterators

Class ArrayListIterator

Implemented Interfaces:
Iterator, ListIterator, ResettableIterator, ResettableListIterator

public class ArrayListIterator
extends ArrayIterator
implements ListIterator, ResettableListIterator

Implements a ListIterator over an array.

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

This iterator does not support add(Object) or remove(), as the array cannot be changed in size. The set(Object) method is supported however.

Version:
$Revision: 1.12 $ $Date: 2004/02/18 00:59:50 $
Authors:
Neil O'Toole
Stephen Colebourne
Phil Steitz
Since:
Commons Collections 3.0
See Also:
ArrayIterator, java.util.Iterator, java.util.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.ArrayIterator

array, endIndex, index, startIndex

Constructor Summary

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

Method Summary

void
add(Object o)
This iterator does not support modification of its backing collection, 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.
Object
next()
Gets the next element from the array.
int
nextIndex()
Gets the next index to be retrieved.
Object
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(Object o)
Sets the element under the cursor.

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

checkBound, getArray, hasNext, next, remove, reset, setArray

Field Details

lastItemIndex

protected int lastItemIndex

Constructor Details

ArrayListIterator

public ArrayListIterator()

ArrayListIterator

public ArrayListIterator(Object array)
Constructs an ArrayListIterator that will iterate over the values in the specified array.
Parameters:
array - the array to iterate over

ArrayListIterator

public ArrayListIterator(Object array,
                         int startIndex)
Constructs an ArrayListIterator 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

ArrayListIterator

public ArrayListIterator(Object array,
                         int startIndex,
                         int endIndex)
Construct an ArrayListIterator 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 (exclusive) to finish iterating at

Method Details

add

public void add(Object o)
This iterator does not support modification of its backing collection, and so will always throw an UnsupportedOperationException when this method is invoked.
See Also:
java.util.ListIterator.set

hasPrevious

public boolean hasPrevious()
Returns true if there are previous elements to return from the array.
Returns:
true if there is a previous element to return

next

public Object next()
Gets the next element from the array.
Overrides:
next in interface ArrayIterator
Returns:
the next element

nextIndex

public int nextIndex()
Gets the next index to be retrieved.
Returns:
the index of the item to be retrieved next

previous

public Object previous()
Gets the previous element from the array.
Returns:
the previous element

previousIndex

public int previousIndex()
Returns:
the index of the item to be retrieved next

reset

public void reset()
Resets the iterator back to the start index.
Specified by:
reset in interface ResettableListIterator
reset in interface ResettableIterator
Overrides:
reset in interface ArrayIterator

set

public void set(Object o)
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.

See Also:
java.util.ListIterator.set

Copyright © 2001-2006 Apache Software Foundation. All Rights Reserved.