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public interface ListIterator
An iterator for lists that allows the programmer to traverse the list in either direction, modify the list during iteration, and obtain the iterator's current position in the list. A 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(). In a list of length n, there are n+1 valid index values, from 0 to n, inclusive.
Element(0) Element(1) Element(2) ... Element(n) ^ ^ ^ ^ ^ Index: 0 1 2 3 n+1
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
Method Summary | |
---|---|
void |
add(Object o)
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. |
Object |
next()
Returns the next element in the list. |
int |
nextIndex()
Returns the index of the element that would be returned by a subsequent call to next. |
Object |
previous()
Returns the previous element in the list. |
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(Object o)
Replaces the last element returned by next or previous with the specified element (optional operation). |
Method Detail |
---|
boolean hasNext()
hasNext
in interface Iterator
Object next()
next
in interface Iterator
NoSuchElementException
- if the iteration has no next element.boolean hasPrevious()
Object previous()
NoSuchElementException
- if the iteration has no previous
element.int nextIndex()
int previousIndex()
void remove()
remove
in interface Iterator
UnsupportedOperationException
- if the remove
operation is not supported by this list iterator.
IllegalStateException
- neither next nor
previous have been called, or remove or
add have been called after the last call to *
next or previous.void set(Object o)
o
- 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 iterator.
ClassCastException
- if the class of the specified element
prevents it from being added to this list.
IllegalArgumentException
- if some aspect of the specified
element prevents it from being added to this list.
IllegalStateException
- if neither next nor
previous have been called, or remove or
add have been called after the last call to
next or previous.void add(Object o)
o
- the element to insert.
UnsupportedOperationException
- if the add method is
not supported by this list iterator.
ClassCastException
- if the class of the specified element
prevents it from being added to this list.
IllegalArgumentException
- if some aspect of this element
prevents it from being added to this list.
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