Help with linked list code.

Question

Here's a basic linked list code that I need help on.
What I need assistance with:
1. How would I rewrite and delete words/phrases in the file IO section of my code?
2. How would I make the code recognize all the words on each line of the linked list? Only the words on the first line of the file go into the linked list.
import java.util.LinkedList;
import java.io.*;
import javax.swing.JOptionPane;
public class LinkedLists {
    public static void delete (LinkedList test)
        int a = Integer.parseInt(JOptionPane.showInputDialog(null,
        "Enter a position to delete"));
        test.remove(a - 1);
        System.out.print(test);
    public static void add (LinkedList test)
        String user = JOptionPane.showInputDialog(null, "What to input?");
        int b = Integer.parseInt(JOptionPane.showInputDialog(null,
                "What position to enter it in?"));
        test.add(b - 1, user);
        System.out.print(test);
    public static void fileRead(LinkedList test) throws IOException
        BufferedReader fileIn;
        String text;
        fileIn = new BufferedReader(new FileReader("z:/data.txt"));
        text = fileIn.readLine();
        fileIn.close();
        int b = Integer.parseInt(JOptionPane.showInputDialog(null,
                "What position to enter it in?"));
        test.add(b - 1, text);
        System.out.print(test);
    public static void fileWrite(LinkedList test) throws IOException
        PrintWriter fileOut;
        fileOut = new PrintWriter(new FileWriter("z:/data.txt",true));
        String user = JOptionPane.showInputDialog(null, "What to input?");
        fileOut.println(user);
        fileOut.close();
        fileRead(test);
    public static void main(String[] args)  {
        LinkedList test = new LinkedList();
        test.addLast("Fly");
        test.addLast("money");
        test.addLast("awesome");
        test.addLast("woot");
        test.addLast("yay");
        System.out.print(test);
        System.out.println();
        int x = Integer.parseInt(JOptionPane.showInputDialog(null,
                "Enter \n1 to Delete \n2 to Add \n3 to read data from file \n4 to write into the file and add to list"));
        if (x == 1) {
            delete(test);
        if (x == 2) {
            add(test);
        if (x == 3) {
            try {
                fileRead(test);
            } catch (IOException e) {
                e.printStackTrace();
        if(x==4)
            try {
                fileWrite(test);
            } catch (IOException e) {
                e.printStackTrace();
}Edited by: Johnston on Sep 16, 2007 1:13 AM

Answer 1

Hi,
Johnston wrote:
1. How would I rewrite and delete words/phrases in the file IO section of my code?You want to replace or remove in/from the file?
First you have to define a file format. This is not a Java technical term, but a thing what you have to keep in mind. Simplest format is:
- each ListItem is one line in the file closed with newline.
Now you can read the file line by line and store the lines in a memory structure (LinkedList for ex ;-)). Then replace or remove the designated elements an write the file new by iterate over the list and write each item as line in the file.
Johnston wrote:
2. How would I make the code recognize all the words on each line of the linked list? Only the words on the first line of the file go into the linked list.You have to read the file line by line and then add each line as item of the list.
Examples for reading/writing textfiles:
http://www.exampledepot.com/egs/java.io/pkg.html#Reading%20and%20Writing
Btw: Deal with Generics (see http://java.sun.com/docs/books/tutorial/extra/generics/index.html) an use this knowledge to declate your List better.
greetings
Axel