Chapter 16, Problem 7PE

Program Plan Intro

Reimplementation of “LinkedList” class

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 “Node.java”, create a class “Node”,
  • Create necessary object variables.
  • Define the constructor to create initial node.
  • Define the method “getData()”,
    • Return the node value.
      • Define the method “getNext()”,
        • Return the next reference.
      • Define the method “setData()”,
        • Set the node value.
• In a file “LinkedList.java”, import the package and create a class “LinkedList”,
  • Declare the object variable.
  • Define the constructor to create an empty 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 front of the linked list,
    • Create a new node.
    • Assign the value to the first reference.
      • Define the method “listIterator()” of type “ListIterator”, that returns an iterator to iterate through the list.
      • Define the method “getFirstNode()” to get the first reference.
• In a file “LinkedListIterator.java”, import the package and create a class “LinkedListIterator”,
  • Declare the necessary object variables.
  • Define the constructor that creates 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.
    • Returns the value.
      • Define the method “hasNext()” that check whether there is next element,
        • Check if position is null,
        • • Returns true if first reference is not null.
            • Otherwise,
              • Returns true, if the next reference of the position is not null.
      • Define the method “add()”,
        • If position is null, call the method “addFirst()”.
        • • Set the first to the position.
            • Otherwise, create a new node.
              • Create a new node.
              • Call the method “setNext()”.
              • Set the new node as the position.
            • Assign the position to previous.
      • Define the method “remove()”,
        • Check if the position is same as previous, throws an exception.
        • If position is same as the first, calls the method “removeFirst()”.
        • Otherwise,
        • • Set the next position to the previous position.
            • Set the previous to the positions.
      • Define the method “set()”,
        • If the position is null, throws an exception.
        • Call the method “setData()”.
• In a file “ListTest.java”, create a class “ListTest”,
  • Define the “main()” method.
    • Create the “LinkedList” object.
    • Call the method “addFirst()” to add “Tommy” to the front of the linked list.
    • Call the method “addFirst()” to add “Roma” to the font of the linked list.
    • Call the method “addFirst()” to add “Harris” to the font of the linked list.
    • Call the method “addFirst()” to add “David” to the font of the linked list.
    • Assign the value returned from the method “listIterator()” calling by  “LinkedList” object.
    • Call the method “next()”.
    • Call the method “next()”.
    • Call the method “add()” to add the element “John”.
    • Call the method “add()” to add the element “Nick”.
    • Call the method “next()”.
    • Call the method “remove()” to remove the last traversed element.
    • Get the iterator.
    • Execute a loop,
      • Print the actual output.
        • • • Print the new line.
            • Print the expected output.
            • Get the iterator.
            • Create a node.