org.apache.commons.collections.iterators
Class SingletonListIterator

java.lang.Object
  |
  +--org.apache.commons.collections.iterators.SingletonListIterator

public class SingletonListIterator
extends Object
implements ListIterator

SingletonIterator is an ListIterator over a single object instance.

Since:
2.1
Version:
$Id: SingletonListIterator.java,v 1.2 2002/08/19 21:56:18 pjack Exp $
Author:
Stephen Colebourne

Constructor Summary
SingletonListIterator(Object object)
          Constructs a new SingletonListIterator.
 
Method Summary
 void add(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.
 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.
 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 always throws UnsupportedOperationException.
 void set(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(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 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 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 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 ListIterator
Returns:
0 or -1 depending on current state.

next

public 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 ListIterator
Returns:
the single object
Throws:
NoSuchElementException - if the single object has already been returned

previous

public Object previous()
Get the previous object from the iterator.

This returns the single object if it has been returned.

Specified by:
previous in interface ListIterator
Returns:
the single object
Throws:
NoSuchElementException - if the single object has not already been returned

remove

public void remove()
Remove always throws UnsupportedOperationException.
Specified by:
remove in interface ListIterator
Throws:
UnsupportedOperationException - always

add

public void add(Object obj)
Add always throws UnsupportedOperationException.
Specified by:
add in interface ListIterator
Throws:
UnsupportedOperationException - always

set

public void set(Object obj)
Set sets the value of the singleton.
Specified by:
set in interface ListIterator
Parameters:
obj - the object to set
Throws:
IllegalStateException - if next has not been called


Copyright © 2001-2002 Apache Software Foundation. Documenation generated October 21 2002.