Chapter 16, Problem 3PP

Program Plan Intro

Enhancement of the methods “get()” and “set()”

Program plan:

• In a file “ListIterator.java”, create an interface “ListIterator”,
  • Declare the method “next()” that moves the iterator past the next element.
  • Declare the method “hasNext()” that check if there is an element after the iterator position.
  • Declare the method “add()”  that adds an element before the position of the iterator and moves the iterator past the added element.
  • Declare the method “remove()” that removes the last traversed element.
  • Declare the method “set()” to set the last traversed element to a previous value.
• In a file “LinkedList.java”, import the package and create a class “LinkedList”,
  • Declare two object variables of type “Node”.
  • Declare the necessary variables.
  • Define the constructor to create an empty linked list.
  • Define the method “size()” that returns the size of linked list.
  • Define the method “getFirst()” that returns the first element in the linked list.
  • Define the method “removeFirst()” to remove the first element in the linked list.
  • Define the method “addFirst()” that adds an element to the linked list.
  • Define the method “get()” ,
    • Check if the last index is either “-1” or greater than or equal to the passed argument, assign the value returned from the method “getNode()” to the last value and assign the argument passed, to the last index.
    • Otherwise, assign the value returned from the method “getNode()” with different argument,  to the last value and assign the argument passed, to the last index.
      • Define the method “set()” ,
        • Get the value returned from the method “getNode()”.
        • Set the new element.
      • Define the method “getNode()”,
        • Check whether the distance is less than or equal to “0” or start contains null value,
        • • If it is true, returns start value.
            • Call the method “getNode()” recursively.
      • Define the method “listIterator” of type “ListIterator”, that returns an iterator for iterating through the list.
      • Create a class “Node”,
        • Declare the object variable for “Object”, and “Node”.
      • Create a class “LinkedListIterator”,
        • Declare the necessary object variables.
        • Define the constructor to create an iterator that points to the front of the linked list.
        • Define the method “next()”,
        • • If there is no next element then throws an exception.
          • Assign the position to the front of the linked list.
          • Check if position is null, set the first element to the position.
          • Otherwise, set the next position to the current position.
            • Define the method “hasNext()” that check whether there is next element.
            • Define the method “add()”,
              • If position is null, call the method “addFirst()”.
                • Set the first to the position.
              • Otherwise, create a new node.
                • Assign the element to the new node.
                • Set the next position to the next pointer of the new node.
                • Set the new node value to the next position.
                • Set the new node as the position.
                • Increment the size.
              • Set the position to the previous node.
            • Define the method “remove()”,
              • If position is same as the previous, throws an exception.
              • If the position is the first position, call the method “removeFirst()”.
              • Otherwise, set the position to the previous position.
                • Increment the size.
              • Set the previous position to the position.
            • Define the method “set()”,
              • If position is null, throw an exception.
              • Set the value to the position.
• In a file “ListTest.java”, create a class “ListTest”,
  • Define the “main()” method.
    • Create “LinkedList” object.
    • Add the element “Tony” to the linked list.
    • Add the element “Juliet” to the linked list.
    • Add the element “Harris” to the linked list.
    • Add the element “David” to the linked list.
    • Print the element returned from the method “get()”.
    • Print new line.
    • Print expected result.
    • Call the method “set()” to set the element “Jerry” to “2”.
    • Print the element returned from the method “get()”.
    • Print new line.
    • Print expected result.