Write a parameterized class definition for a doubly linked list that has a parameter for the type of data stored in a node. Make the node class an inner class. Choosing which methods to define is part of this project. Also, write a program to thoroughly test your class definition.

Question

This program is based on code from Listing 12.9. The solution given here includes support for iteration, both forward and reverse. Both forward and reverse iteration use the moreToIterate method, but backward iteration uses the resetIterationReverse rather than resetIteration. The ListNode class includes a previous instance variable which makes the previous variable in the outer class unnecessary. To make reverse iteration (especially resetIterationReverse) easier to write, there is a reference to the tail of the list as well as to the head of the list. An additional method, findInList, looks for an element in the list and sets current to point to that element if it is found. If it is not found, current is set to null. The method showListState is for testing and debugging purposes and prints the head of the list, the current element, the tail, and the number of elements in the list.

Answer 1

See the code in DoublyLinkedList.java, and DoublyLinkedListDemo.java.