For the following method of interface ListIterator, answer the questions: void s

Question

For the following method of interface ListIterator, answer the questions:

void set(E obj);

In what class(es) could this method be implemented?

In what class should this method be implemented?

Write a thorough test case for the method:

Write the method:

What is the efficiency of this method? Justify your answer.

For the following method of interface ListIterator, answer the questions:

void set(E obj);

In what class(es) could this method be implemented?

In what class should this method be implemented?

Write a thorough test case for the method:

Write the method:

What is the efficiency of this method? Justify your answer.

Explanation / Answer

1. Any class which implements the ListIterator Interface can implement set method. set method replace the element last returned by a call to next or previous with a given object.

2. set method or the ListIterator, in general, should be implemented for classes which has some sequential data structure attached to it like ArrayList, Set, Vector etc. A ListIterator basically iterate over this data structure and perform the action accordingly.

3. Test:

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

public class TestListIterator {
   public static void main(String args[]) {
       ArrayList<String> al = new ArrayList<String>();
       al.add("Apple");
       al.add("Mango");
       al.add("Banana");

       ListIterator<String> itr = al.listIterator();
       System.out.println("traversing elements ....");
       while (itr.hasNext()) {
           String val = itr.next();
           System.out.println(val);
           if(val.equals("Mango")){
               itr.set("Orange");
           }
       }
       System.out.println(al);
   }
}

4. The fundamental requirement of an Iterator is its .next() method. Each .next() takes O(1) (in case of a LinkedList) which combines to O(n). If we put this inside a loop to use a set() method, the total time complexiety comes out to be O(n^2). As compared to normal loop, it seems to be less efficient but mostly the efficiency depends on the type of data structure on which the Iterator is working.

Related Questions

Navigate

• Browse (All)
• Browse F
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.