java.lang.Object
- org.apache.commons.collections.iterators.ReverseListIterator

All Implemented Interfaces:

Iterator, ListIterator, ResettableIterator, ResettableListIterator
```
public class ReverseListIterator
extends Object
implements ResettableListIterator
```
Iterates backwards through a List, starting with the last element and continuing to the first. This is useful for looping around a list in reverse order without needing to actually reverse the list.
The first call to next() will return the last element from the list, and so on. The hasNext() method works in concert with the next() method as expected. However, the nextIndex() method returns the correct index in the list, thus it starts high and reduces as the iteration continues. The previous methods work similarly.

Since:

Commons Collections 3.2

Version:

$Revision: $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $

Author:

Serge Knystautas, Stephen Colebourne

Constructor Summary

Constructors
Constructor Description

ReverseListIterator(List list)
Constructor that wraps a list.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`add(Object obj)`	Adds a new element to the list between the next and previous elements.
`boolean`	`hasNext()`	Checks whether there is another element.
`boolean`	`hasPrevious()`	Checks whether there is a previous element.
`Object`	`next()`	Gets the next element.
`int`	`nextIndex()`	Gets the index of the next element.
`Object`	`previous()`	Gets the previous element.
`int`	`previousIndex()`	Gets the index of the previous element.
`void`	`remove()`	Removes the last returned element.
`void`	`reset()`	Resets the iterator back to the start (which is the end of the list as this is a reversed iterator)
`void`	`set(Object obj)`	Replaces the last returned element.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Iterator
forEachRemaining

- Constructor Detail
  - ReverseListIterator
```
public ReverseListIterator(List list)
```
    Constructor that wraps a list.
    
    Parameters:
    
    list - the list to create a reversed iterator for
    
    Throws:
    
    NullPointerException - if the list is null
- Method Detail
  - hasNext
```
public boolean hasNext()
```
    Checks whether there is another element.
    
    Specified by:
    
    hasNext in interface Iterator
    
    Specified by:
    
    hasNext in interface ListIterator
    
    Returns:
    
    true if there is another element
  - next
```
public Object next()
```
    Gets the next element. The next element is the previous in the list.
    
    Specified by:
    
    next in interface Iterator
    
    Specified by:
    
    next in interface ListIterator
    
    Returns:
    
    the next element in the iterator
  - nextIndex
```
public int nextIndex()
```
    Gets the index of the next element.
    
    Specified by:
    
    nextIndex in interface ListIterator
    
    Returns:
    
    the index of the next element in the iterator
  - hasPrevious
```
public boolean hasPrevious()
```
    Checks whether there is a previous element.
    
    Specified by:
    
    hasPrevious in interface ListIterator
    
    Returns:
    
    true if there is a previous element
  - previous
```
public Object previous()
```
    Gets the previous element. The next element is the previous in the list.
    
    Specified by:
    
    previous in interface ListIterator
    
    Returns:
    
    the previous element in the iterator
  - previousIndex
```
public int previousIndex()
```
    Gets the index of the previous element.
    
    Specified by:
    
    previousIndex in interface ListIterator
    
    Returns:
    
    the index of the previous element in the iterator
  - remove
```
public void remove()
```
    Removes the last returned element.
    
    Specified by:
    
    remove in interface Iterator
    
    Specified by:
    
    remove in interface ListIterator
    
    Throws:
    
    UnsupportedOperationException - if the list is unmodifiable
    
    IllegalStateException - if there is no element to remove
  - set
```
public void set(Object obj)
```
    Replaces the last returned element.
    
    Specified by:
    
    set in interface ListIterator
    
    Parameters:
    
    obj - the object to set
    
    Throws:
    
    UnsupportedOperationException - if the list is unmodifiable
    
    IllegalStateException - if the iterator is not in a valid state for set
  - add
```
public void add(Object obj)
```
    Adds a new element to the list between the next and previous elements.
    
    Specified by:
    
    add in interface ListIterator
    
    Parameters:
    
    obj - the object to add
    
    Throws:
    
    UnsupportedOperationException - if the list is unmodifiable
    
    IllegalStateException - if the iterator is not in a valid state for set
  - reset
```
public void reset()
```
    Resets the iterator back to the start (which is the end of the list as this is a reversed iterator)
    
    Specified by:
    
    reset in interface ResettableIterator
    
    Specified by:
    
    reset in interface ResettableListIterator

Class ReverseListIterator

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Iterator

Constructor Detail

ReverseListIterator

Method Detail

hasNext

next

nextIndex

hasPrevious

previous

previousIndex

remove

set

add

reset