Interface ListIterator<E>

Type Parameters:
E - the type of elements returned by this list iterator
All Superinterfaces:
Iterator<E>
public interfaceListIterator<E>extendsIterator<E>
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. AListIterator has no current element; itscursor position always lies between the element that would be returned by a call toprevious() and the element that would be returned by a call tonext(). An iterator for a list of lengthn hasn+1 possible cursor positions, as illustrated by the carets (^) below:
                      Element(0)   Element(1)   Element(2)   ... Element(n-1) cursor positions:  ^            ^            ^            ^                  ^
Note that theremove() andset(Object) methods arenot defined in terms of the cursor position; they are defined to operate on the last element returned by a call tonext() orprevious().

This interface is a member of the Java Collections Framework.

Since:
1.2
See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    add(E e)
    Inserts the specified element into the list (optional operation).
    boolean
    Returnstrue if this list iterator has more elements when traversing the list in the forward direction.
    boolean
    Returnstrue if this list iterator has more elements when traversing the list in the reverse direction.
    Returns the next element in the list and advances the cursor position.
    int
    Returns the index of the element that would be returned by a subsequent call tonext().
    Returns the previous element in the list and moves the cursor position backwards.
    int
    Returns the index of the element that would be returned by a subsequent call toprevious().
    void
    Removes from the list the last element that was returned bynext() orprevious() (optional operation).
    void
    set(E e)
    Replaces the last element returned bynext() orprevious() with the specified element (optional operation).

    Methods declared in interface java.util.Iterator

    forEachRemaining

  • Method Details

    • hasNext

      boolean hasNext()
      Returnstrue if this list iterator has more elements when traversing the list in the forward direction. (In other words, returnstrue ifnext() would return an element rather than throwing an exception.)
      Specified by:
      hasNext in interface Iterator<E>
      Returns:
      true if the list iterator has more elements when traversing the list in the forward direction

    • next

      E next()
      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 toprevious() to go back and forth. (Note that alternating calls tonext andprevious will return the same element repeatedly.)
      Specified by:
      next in interface Iterator<E>
      Returns:
      the next element in the list
      Throws:
      NoSuchElementException - if the iteration has no next element

    • hasPrevious

      boolean hasPrevious()
      Returnstrue if this list iterator has more elements when traversing the list in the reverse direction. (In other words, returnstrue ifprevious() would return an element rather than throwing an exception.)
      Returns:
      true if the list iterator has more elements when traversing the list in the reverse direction

    • previous

      E previous()
      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 tonext() to go back and forth. (Note that alternating calls tonext andprevious will return the same element repeatedly.)
      Returns:
      the previous element in the list
      Throws:
      NoSuchElementException - if the iteration has no previous element

    • nextIndex

      int nextIndex()
      Returns the index of the element that would be returned by a subsequent call tonext(). (Returns list size if the list iterator is at the end of the list.)
      Returns:
      the index of the element that would be returned by a subsequent call tonext, or list size if the list iterator is at the end of the list

    • previousIndex

      int previousIndex()
      Returns the index of the element that would be returned by a subsequent call toprevious(). (Returns -1 if the list iterator is at the beginning of the list.)
      Returns:
      the index of the element that would be returned by a subsequent call toprevious, or -1 if the list iterator is at the beginning of the list

    • remove

      void remove()
      Removes from the list the last element that was returned bynext() orprevious() (optional operation). This call can only be made once per call tonext orprevious. It can be made only ifadd(E) has not been called after the last call tonext orprevious.
      Specified by:
      remove in interface Iterator<E>
      Throws:
      UnsupportedOperationException - if theremove operation is not supported by this list iterator
      IllegalStateException - if neithernext norprevious have been called, orremove oradd have been called after the last call tonext orprevious

    • set

      void set(E e)
      Replaces the last element returned bynext() orprevious() with the specified element (optional operation). This call can be made only if neitherremove() noradd(E) have been called after the last call tonext orprevious.
      Parameters:
      e - the element with which to replace the last element returned bynext orprevious
      Throws:
      UnsupportedOperationException - if theset 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 neithernext norprevious have been called, orremove oradd have been called after the last call tonext orprevious

    • add

      void add(E e)
      Inserts the specified element into the list (optional operation). The element is inserted immediately before the element that would be returned bynext(), if any, and after the element that would be returned byprevious(), 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 tonext would be unaffected, and a subsequent call toprevious would return the new element. (This call increases by one the value that would be returned by a call tonextIndex orpreviousIndex.)
      Parameters:
      e - the element to insert
      Throws:
      UnsupportedOperationException - if theadd 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