ListIterator<E> (GNU Classpath 0.94-pre Documentation)

An extended version of Iterator to support the extra features of Lists. The elements may be accessed in forward or reverse order, elements may be replaced as well as removed, and new elements may be inserted, during the traversal of the list.

A list with n elements provides n+1 iterator positions (the front, the end, or between two elements). Note that remove and set operate on the last element returned, whether it was by next or previous.

Since: 1.2

UNKNOWN: updated to 1.4

Method Summary
void	add(E o) Insert an element into the list at the current position of the iterator (optional operation).
boolean	hasNext() Tests whether there are elements remaining in the list in the forward direction.
boolean	hasPrevious() Tests whether there are elements remaining in the list in the reverse direction.
E	next() Obtain the next element in the list in the forward direction.
int	nextIndex() Find the index of the element that would be returned by a call to next.
E	previous() Obtain the next element in the list in the reverse direction.
int	previousIndex() Find the index of the element that would be returned by a call to previous.
void	remove() Remove from the list the element last returned by a call to next or previous (optional operation).
void	set(E o) Replace the element last returned by a call to next or previous with a given object (optional operation).

Method Detail

add

Insert an element into the list at the current position of the iterator (optional operation). The element is inserted in between the element that would be returned by previous and the element that would be returned by next. After the insertion, a subsequent call to next is unaffected, but a call to previous returns the item that was added. The values returned by nextIndex() and previousIndex() are incremented.

Parameters: o the object to insert into the list

Throws: ClassCastException if the object is of a type which cannot be added to this list. IllegalArgumentException if some other aspect of the object stops it being added to this list. UnsupportedOperationException if this ListIterator does not support the add operation.

hasNext

Tests whether there are elements remaining in the list in the forward direction. In other words, next() will not fail with a NoSuchElementException.

Returns: true if the list continues in the forward direction

hasPrevious

Tests whether there are elements remaining in the list in the reverse direction. In other words, previous() will not fail with a NoSuchElementException.

Returns: true if the list continues in the reverse direction

Obtain the next element in the list in the forward direction. Repeated calls to next may be used to iterate over the entire list, or calls to next and previous may be used together to go forwards and backwards. Alternating calls to next and previous will return the same element.

Returns: the next element in the list in the forward direction

Throws: NoSuchElementException if there are no more elements

nextIndex

Find the index of the element that would be returned by a call to next. If hasNext() returns false, this returns the list size.

Returns: the index of the element that would be returned by next()

Obtain the next element in the list in the reverse direction. Repeated calls to previous may be used to iterate backwards over the entire list, or calls to next and previous may be used together to go forwards and backwards. Alternating calls to next and previous will return the same element.

Returns: the next element in the list in the reverse direction

Throws: NoSuchElementException if there are no more elements

previousIndex

Find the index of the element that would be returned by a call to previous. If hasPrevious() returns false, this returns -1.

Returns: the index of the element that would be returned by previous()

remove

Remove from the list the element last returned by a call to next or previous (optional operation). This method may only be called if neither add nor remove have been called since the last call to next or previous.

Throws: IllegalStateException if neither next or previous have been called, or if add or remove has been called since the last call to next or previous UnsupportedOperationException if this ListIterator does not support the remove operation

set

Replace the element last returned by a call to next or previous with a given object (optional operation). This method may only be called if neither add nor remove have been called since the last call to next or previous.

Parameters: o the object to replace the element with

Throws: ClassCastException the object is of a type which cannot be added to this list IllegalArgumentException some other aspect of the object stops it being added to this list IllegalStateException if neither next or previous have been called, or if add or remove has been called since the last call to next or previous UnsupportedOperationException if this ListIterator does not support the set operation

Interface ListIterator<E>