org.apache.commons.collections.iterators
Class SingletonListIterator

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

All Implemented Interfaces:

java.util.Iterator, java.util.ListIterator, ResettableIterator, ResettableListIterator

public class SingletonListIterator
extends java.lang.Object
implements java.util.ListIterator, ResettableListIterator

SingletonIterator is an ListIterator over a single object instance.

Since:

Commons Collections 2.1

Version:

$Revision: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $

Author:

Stephen Colebourne, Rodney Waldhoff

Constructor Summary

SingletonListIterator(java.lang.Object object)
Constructs a new SingletonListIterator.

Method Summary

void	add(java.lang.Object obj) Add always throws UnsupportedOperationException.
boolean	hasNext() Is another object available from the iterator?
boolean	hasPrevious() Is a previous object available from the iterator?
java.lang.Object	next() Get the next object from the iterator.
int	nextIndex() Returns the index of the element that would be returned by a subsequent call to next.
java.lang.Object	previous() Get the previous object from the iterator.
int	previousIndex() Returns the index of the element that would be returned by a subsequent call to previous.
void	remove() Remove the object from this iterator.
void	reset() Reset the iterator back to the start.
void	set(java.lang.Object obj) Set sets the value of the singleton.

Methods inherited from class java.lang.Object

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

Constructor Detail

SingletonListIterator

public SingletonListIterator(java.lang.Object object)

Constructs a new SingletonListIterator.

Parameters:

object - the single object to return from the iterator

Method Detail

hasNext

public boolean hasNext()

Is another object available from the iterator?

This returns true if the single object hasn't been returned yet.

Specified by:

hasNext in interface java.util.Iterator

Specified by:

hasNext in interface java.util.ListIterator

Returns:

true if the single object hasn't been returned yet

hasPrevious

public boolean hasPrevious()

Is a previous object available from the iterator?

This returns true if the single object has been returned.

Specified by:

hasPrevious in interface java.util.ListIterator

Returns:

true if the single object has been returned

nextIndex

public int nextIndex()

Returns the index of the element that would be returned by a subsequent call to next.

Specified by:

nextIndex in interface java.util.ListIterator

Returns:

0 or 1 depending on current state.

previousIndex

public int previousIndex()

Returns the index of the element that would be returned by a subsequent call to previous. A return value of -1 indicates that the iterator is currently at the start.

Specified by:

previousIndex in interface java.util.ListIterator

Returns:

0 or -1 depending on current state.

next

public java.lang.Object next()

Get the next object from the iterator.

This returns the single object if it hasn't been returned yet.

Specified by:

next in interface java.util.Iterator

Specified by:

next in interface java.util.ListIterator

Returns:

the single object

Throws:

java.util.NoSuchElementException - if the single object has already been returned

previous

public java.lang.Object previous()

Get the previous object from the iterator.

This returns the single object if it has been returned.

Specified by:

previous in interface java.util.ListIterator

Returns:

the single object

Throws:

java.util.NoSuchElementException - if the single object has not already been returned

remove

public void remove()

Remove the object from this iterator.

Specified by:

remove in interface java.util.Iterator

Specified by:

remove in interface java.util.ListIterator

Throws:

java.lang.IllegalStateException - if the next or previous method has not yet been called, or the remove method has already been called after the last call to next or previous.

add

public void add(java.lang.Object obj)

Add always throws UnsupportedOperationException.

Specified by:

add in interface java.util.ListIterator

Throws:

java.lang.UnsupportedOperationException - always

set

public void set(java.lang.Object obj)

Set sets the value of the singleton.

Specified by:

set in interface java.util.ListIterator

Parameters:

obj - the object to set

Throws:

java.lang.IllegalStateException - if next has not been called or the object has been removed

reset

public void reset()

Reset the iterator back to the start.

Specified by:

reset in interface ResettableIterator

Specified by:

reset in interface ResettableListIterator