public interface ListIterator<E> extends Iterator<E>
ListIterator
has no current element; its cursor position always
lies between the element that would be returned by a call
to previous()
and the element that would be
returned by a call to next()
.
An iterator for a list of length n
has n+1
possible
cursor positions, as illustrated by the carets (^
) below:
Element(0) Element(1) Element(2) ... Element(n-1) cursor positions: ^ ^ ^ ^ ^Note that the
remove()
and set(Object)
methods are
not defined in terms of the cursor position; they are defined to
operate on the last element returned by a call to next()
or
previous()
.
This interface is a member of the Java Collections Framework.
Collection
,
List
,
Iterator
,
Enumeration
,
List.listIterator()
Modifier and Type | Method and Description |
---|---|
void |
add(E e)
Inserts the specified element into the list (optional operation).
|
boolean |
hasNext()
Returns
true if this list iterator has more elements when
traversing the list in the forward direction. |
boolean |
hasPrevious()
Returns
true if this list iterator has more elements when
traversing the list in the reverse direction. |
E |
next()
Returns the next element in the list and advances the cursor position.
|
int |
nextIndex()
Returns the index of the element that would be returned by a
subsequent call to
next() . |
E |
previous()
Returns the previous element in the list and moves the cursor
position backwards.
|
int |
previousIndex()
Returns the index of the element that would be returned by a
subsequent call to
previous() . |
void |
remove()
Removes from the list the last element that was returned by
next() or previous() (optional operation). |
void |
set(E e)
Replaces the last element returned by
next() or
previous() with the specified element (optional operation). |
void add(E e)
next()
, if any, and after the element
that would be returned by previous()
, if any. (If the
list contains no elements, the new element becomes the sole element
on the list.) The new element is inserted before the implicit
cursor: a subsequent call to next
would be unaffected, and a
subsequent call to previous
would return the new element.
(This call increases by one the value that would be returned by a
call to nextIndex
or previousIndex
.)e
- the element to insertUnsupportedOperationException
- if the add
method is
not supported by this list iteratorClassCastException
- if the class of the specified element
prevents it from being added to this listIllegalArgumentException
- if some aspect of this element
prevents it from being added to this listboolean hasNext()
true
if this list iterator has more elements when
traversing the list in the forward direction. (In other words,
returns true
if next()
would return an element rather
than throwing an exception.)boolean hasPrevious()
true
if this list iterator has more elements when
traversing the list in the reverse direction. (In other words,
returns true
if previous()
would return an element
rather than throwing an exception.)true
if the list iterator has more elements when
traversing the list in the reverse directionE next()
previous()
to go back and forth.
(Note that alternating calls to next
and previous
will return the same element repeatedly.)next
in interface Iterator<E>
NoSuchElementException
- if the iteration has no next elementint nextIndex()
next()
. (Returns list size if the list
iterator is at the end of the list.)next
, or list size if the list
iterator is at the end of the listE previous()
next()
to go back and forth. (Note that alternating calls
to next
and previous
will return the same
element repeatedly.)NoSuchElementException
- if the iteration has no previous
elementint previousIndex()
previous()
. (Returns -1 if the list
iterator is at the beginning of the list.)previous
, or -1 if the list
iterator is at the beginning of the listvoid remove()
next()
or previous()
(optional operation). This call can
only be made once per call to next
or previous
.
It can be made only if add(E)
has not been
called after the last call to next
or previous
.remove
in interface Iterator<E>
UnsupportedOperationException
- if the remove
operation is not supported by this list iteratorIllegalStateException
- if neither next
nor
previous
have been called, or remove
or
add
have been called after the last call to
next
or previous
void set(E e)
next()
or
previous()
with the specified element (optional operation).
This call can be made only if neither remove()
nor add(E)
have been called after the last call to next
or
previous
.e
- the element with which to replace the last element returned by
next
or previous
UnsupportedOperationException
- if the set
operation
is not supported by this list iteratorClassCastException
- if the class of the specified element
prevents it from being added to this listIllegalArgumentException
- if some aspect of the specified
element prevents it from being added to this listIllegalStateException
- if neither next
nor
previous
have been called, or remove
or
add
have been called after the last call to
next
or previous
Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. Use of this specification is subject to license terms.