Package org.apache.commons.collections4.iterators

Class ReverseListIterator<E>

java.lang.Object
org.apache.commons.collections4.iterators.ReverseListIterator<E>
Type Parameters:
E - the type of elements returned by this iterator.
All Implemented Interfaces:
Iterator<E>, ListIterator<E>, OrderedIterator<E>, ResettableIterator<E>, ResettableListIterator<E>
public class ReverseListIterator<E> extends Object implements ResettableListIterator<E>
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:
3.2

  • Constructor Summary

    Constructors
    Constructor
    Description
    ReverseListIterator(List<E> list)
    Constructor that wraps a list.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    add(E 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.
    E
    next()
    Gets the next element.
    int
    nextIndex()
    Gets the index of the next element.
    E
    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(E 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