Table of The Methods Defined by ListIterator
| Method | Description |
| 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. A NoSuchElementException is thrown |
| if there is not a 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. A NoSuchElementException is thrown |
| if there is not a 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. An IllegalStateException |
| is thrown if remove( ) is called before next( ) or previous( ) is invoked. | |
| void set(E obj) | Assigns obj to the current element. This is the element last returned |
| by a call to either next( ) or previous( ). |
Demonstrate iterators
import java.util.*;
class IteratorDemo {
public static void main(String args[]) { // Create an array list.
ArrayList<String> al = new ArrayList<String>();
//Add elements to the array list. al.add("C");
al.add("A");
al.add("E");
al.add("B");
al.add("D");
al.add("F");
//Use iterator to display contents of al. System.out.print("Original contents of al: "); Iterator<String> itr = al.iterator(); while(itr.hasNext()) {
String element = itr.next(); System.out.print(element + " ");
}
System.out.println();
//Modify objects being iterated. ListIterator<String> litr = al.listIterator(); while(litr.hasNext()) {
String element = litr.next(); litr.set(element + "+");
}
System.out.print("Modified contents of al: "); itr = al.iterator(); while(itr.hasNext()) {
String element = itr.next(); System.out.print(element + " ");
}
System.out.println();
//Now, display the list backwards. System.out.print("Modified list backwards: "); while(litr.hasPrevious()) {
String element = litr.previous(); System.out.print(element + " ");
}
System.out.println();
}
}
Original contents of al: C A E B D F
Modified contents of al: C+ A+ E+ B+ D+ F+
Modified list backwards: F+ D+ B+ E+ A+ C+