import java.io.File;
import java.util.Scanner;
import javax.swing.JOptionPane;
import javax.swing.JTextArea;
import javax.swing.JScrollPane;


public class SingleLinkedListExerciseSolution {
    
    static class Node<T> {
        T data;
        Node<T> next;
        Node() {}
        
        Node(T data) {
            this.data = data;
        } // end
        
        Node(T data, Node<T> next) {
            this.data = data;
            this.next = next;
        } // end
        
        public String toString() {
            return data + "";
        } // end toString
        
    } // end Node
    
    public SingleLinkedListExerciseSolution() {
        Node<String> header = new Node<String>();
        try {
            Scanner fileScanner = new Scanner(new File("src/SingleLinkedListExercise.java"));
            fileScanner.useDelimiter("[^a-zA-Z]+");
            // read and store in the list all unique words from the file
            while( fileScanner.hasNext() ) {
                String aWord = fileScanner.next();
                Node<String> p = header;
                // go through the list until the end or a match of aWord is found
                while( p.next != null ) {
                    if( p.next.data.equals(aWord) ) break;
                    p = p.next;
                }// end while
                // Now either p.next == null or aWord is already on the list 
                // if p.next == null then add it to the list
                if( p.next == null ) p.next = new Node<String>(aWord, p.next);
            } // end while
    } catch(Exception e) {
        e.printStackTrace();;
    } // end try/catch
    JTextArea outArea = new JTextArea(listToString(header),30,40);
    JOptionPane.showMessageDialog(null,new JScrollPane(outArea));
} // end constructor

String listToString(Node header) {
    String out = "";
    Node p = header;
    while( p.next != null ) {
        out += p.next + "\n";
        p = p.next;
    } // end while
    return out;
} // end listToString


public static void main(String[] args) {
    new SingleLinkedListExerciseSolution();
    System.exit(0);
} // end main

} // end SingleLinkedListExerciseSolution