ListIterator

ListIterator extends Iterator to allow bidirectional traversal of a list, and the modification of elements. ListIterator is generic interfaces:

interface ListIterator<E>

E specifies the type of objects being iterated.

The methods declared by ListIterator are

void add(E obj): Inserts obj into the list in front of the element that will be returned by the next call to next( ).
boolean hasNext( ): Returns true if there is a next element. Otherwise, returns false.
boolean hasPrevious( ): Returns true if there is a previous element. Otherwise, returns false.
E next( ): Returns the next element.
int nextIndex( ): Returns the index of the next element. If there is not a next element, returns the size of the list.
E previous( ): Returns the previous element.
int previousIndex( ): Returns the index of the previous element. If there is not a previous element, returns -1.
void remove( ): Removes the current element from the list.
void set(E obj): Assigns obj to the current element.

 
import java.util.ArrayList;
import java.util.ListIterator;

public class Main {
  public static void main(String args[]) {
    ArrayList<String> al = new ArrayList<String>();
    al.add("C");
    al.add("A");
    al.add("E");
    al.add("B");
    al.add("D");
    al.add("F");
    ListIterator<String> litr = al.listIterator();
    while (litr.hasNext()) {
      String element = litr.next();
      litr.set(element + "+");
    }
    while (litr.hasPrevious()) {
      String element = litr.previous();
      System.out.println(element + " ");
    }
  }
}

ListIterator can access the collection in either the forward or backward direction and can modify an element. Otherwise, ListIterator is used just like Iterator.

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