Added in API level 1

ListIterator

interface ListIterator<E : Any!> : MutableIterator<E>

java.util.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(). 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(java.lang.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.

Summary

Public methods
abstract Unit	`add(e: E)` Inserts the specified element into the list (optional operation).
abstract Boolean	`hasNext()` Returns `true` if this list iterator has more elements when traversing the list in the forward direction.
abstract Boolean	`hasPrevious()` Returns `true` if this list iterator has more elements when traversing the list in the reverse direction.
abstract E	`next()` Returns the next element in the list and advances the cursor position.
abstract Int	`nextIndex()` Returns the index of the element that would be returned by a subsequent call to `next`.
abstract E	`previous()` Returns the previous element in the list and moves the cursor position backwards.
abstract Int	`previousIndex()` Returns the index of the element that would be returned by a subsequent call to `previous`.
abstract Unit	`remove()` Removes from the list the last element that was returned by `next` or `previous` (optional operation).
abstract Unit	`set(e: E)` Replaces the last element returned by `next` or `previous` with the specified element (optional operation).

Public methods

add

Added in API level 1

abstract fun add(e: E): Unit

Inserts the specified element into the list (optional operation). The element is inserted immediately before the element that would be returned by 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.)

Parameters
`e`	E: the element to insert

Exceptions
`java.lang.UnsupportedOperationException`	if the `add` method is not supported by this list iterator
`java.lang.ClassCastException`	if the class of the specified element prevents it from being added to this list
`java.lang.IllegalArgumentException`	if some aspect of this element prevents it from being added to this list

hasNext

Added in API level 1

abstract fun hasNext(): Boolean

Returns 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.)

Return
`Boolean`	`true` if the list iterator has more elements when traversing the list in the forward direction

hasPrevious

Added in API level 1

abstract fun hasPrevious(): Boolean

Returns 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.)

Return
`Boolean`	`true` if the list iterator has more elements when traversing the list in the reverse direction

Added in API level 1

abstract fun next(): E

Returns the next element in the list and advances the cursor position. This method may be called repeatedly to iterate through the list, or intermixed with calls to previous to go back and forth. (Note that alternating calls to next and previous will return the same element repeatedly.)

Return
`E`	the next element in the list

Exceptions
`java.util.NoSuchElementException`	if the iteration has no next element

nextIndex

Added in API level 1

abstract fun nextIndex(): Int

Returns the index of the element that would be returned by a subsequent call to next. (Returns list size if the list iterator is at the end of the list.)

Return
`Int`	the index of the element that would be returned by a subsequent call to `next`, or list size if the list iterator is at the end of the list

Added in API level 1

abstract fun previous(): E

Returns the previous element in the list and moves the cursor position backwards. This method may be called repeatedly to iterate through the list backwards, or intermixed with calls to next to go back and forth. (Note that alternating calls to next and previous will return the same element repeatedly.)

Return
`E`	the previous element in the list

Exceptions
`java.util.NoSuchElementException`	if the iteration has no previous element

previousIndex

Added in API level 1

abstract fun previousIndex(): Int

Returns the index of the element that would be returned by a subsequent call to previous. (Returns -1 if the list iterator is at the beginning of the list.)

Return
`Int`	the index of the element that would be returned by a subsequent call to `previous`, or -1 if the list iterator is at the beginning of the list

remove

Added in API level 1

abstract fun remove(): Unit

Removes from the list the last element that was returned by 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 has not been called after the last call to next or previous.

Exceptions
`java.lang.UnsupportedOperationException`	if the `remove` operation is not supported by this list iterator
`java.lang.IllegalStateException`	if neither `next` nor `previous` have been called, or `remove` or `add` have been called after the last call to `next` or `previous`

set

Added in API level 1

abstract fun set(e: E): Unit

Replaces the last element returned by next or previous with the specified element (optional operation). This call can be made only if neither remove nor add have been called after the last call to next or previous.

Parameters
`e`	E: the element with which to replace the last element returned by `next` or `previous`

Exceptions
`java.lang.UnsupportedOperationException`	if the `set` operation is not supported by this list iterator
`java.lang.ClassCastException`	if the class of the specified element prevents it from being added to this list
`java.lang.IllegalArgumentException`	if some aspect of the specified element prevents it from being added to this list
`java.lang.IllegalStateException`	if neither `next` nor `previous` have been called, or `remove` or `add` have been called after the last call to `next` or `previous`