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java.util

Interface ListIterator

java.lang.Object
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+--java.util.Iterator
   |
   +--java.util.ListIterator

All Implemented Interfaces:

Iterator


public interface ListIterator

implements Iterator

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:Authors:See Also:

Method Summary

voidadd(java.lang.Object o)

Insert an element into the list at the current position of the iterator (optional operation).
booleanhasNext()

Tests whether there are elements remaining in the list in the forward direction.
booleanhasPrevious()

Tests whether there are elements remaining in the list in the reverse direction.
java.lang.Objectnext()

Obtain the next element in the list in the forward direction.
intnextIndex()

Find the index of the element that would be returned by a call to next.
java.lang.Objectprevious()

Obtain the next element in the list in the reverse direction.
intpreviousIndex()

Find the index of the element that would be returned by a call to previous.
voidremove()

Remove from the list the element last returned by a call to next or previous (optional operation).
voidset(java.lang.Object o)

Replace the element last returned by a call to next or previous with a given object (optional operation).

Method Details

add

public void add(java.lang.Object o)

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:

Throws:


hasNext

public boolean 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:


hasPrevious

public boolean 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:


next

public Object next()

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:

Throws:


nextIndex

public int 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:


previous

public Object previous()

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:

Throws:


previousIndex

public int previousIndex()

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

Returns:


remove

public void 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:


set

public void set(java.lang.Object o)

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:

Throws: