Doubly link list question

Question

I desparately need help with these topic. Currently, I am doing a project using doubly link list data structure and swing components. However, I just could not get the data items of the doubly link list to display on the JTextArea. Is this possible at all or does anybody out there know in anyway to solve this problem?

Answer 1

Thanks a lot for the timely reply amolk. Here is the sample code you request for:
//The following code is my Link class:
import java.io.Serializable;
public class Link implements Serializable
public String dTitle, dPublisher, dCategory, dUserlevel, dDescription, dISBN, dDay, dMonth, dYear;
public float dPrice;
public int dQuantity;
public Link next; // next link in list
public Link previous; // previous link in list
public Link(String tit, String pub, String cat, float price, int qty, String ISBN, String day, String month, String year, String level, String des) // constructor
dTitle = tit;
dPublisher = pub;
dCategory = cat;
dPrice = price;
dQuantity = qty;
dISBN = ISBN;
dDay = day;
dMonth = month;
dYear = year;
dUserlevel = level;
dDescription = des;
public void displayLink()
System.out.println(dTitle + "");
} // end class Link
//The following is the actual doubly link list code
import java.io.Serializable;
public class DoublyLinkedList implements Serializable
public String back;
public boolean notFound = false;
private Link first; // ref to first item
private Link last; // ref to last item
public DoublyLinkedList() // constructor
first = null; // no items on list yet
last = null;
public boolean isEmpty() // true if no links
return first==null;
public void insertFirst(String title, String publisher, String category, float price, int quantity, String ISBN, String day, String month, String year, String userlevel, String description) // insert at front of list
Link newLink = new Link(title, publisher, category,price, quantity, ISBN, day, month, year, userlevel, description); // make new link
if( isEmpty() ) // if empty list,
last = newLink; // newLink <-- last
else
first.previous = newLink; // newLink <-- old first
newLink.next = first; // newLink --> old first
first = newLink; // first --> newLink
public Link deleteFirst() // delete first link
{                              // (assumes non-empty list)
Link temp = first;
if(first.next == null) // if only one item
last = null; // null <-- last
else
first.next.previous = null; // null <-- old next
first = first.next; // first --> old next
return temp;
public void displayForward()
     System.out.println("first --> last): ");
Link current = first; // start at beginning
while(current != null) // until end of list,
current.displayLink(); //display data
current = current.next; // move to next link
System.out.println("");
//Hoping to hear from you soon.