how to create a linked list data structure from given code

[Hati Mutasa]

I am fairly new to Java and am stuck on trying to understand how to create a dynamic list to accept an Author name, Paper title, Author email address, and rate a paper using the following classes below


/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

package DataStructuresAssignment;

/**
 *
 * @author Jane
 */
import java.io.IOException;

public class DocumentList {

    public static void main(String[] args) throws IOException {
        DocumentListApplication DLA = new DocumentListApplication();
    }
}

package DataStructuresAssignment;

/**
* Defines the action codes for DocumentList
* @author Jane
*/

public class ActionCodes {

    static final int ADD_PAPER = 1;
    static final int DISPLAY_PAPER = 2;
    static final int DELETE_PAPER = 3;
    static final int ADD_AUTHOR = 4;
    static final int REMOVE_AUTHOR = 5;
    static final int LIST_PAPERS = 6;
    static final int LIST_AUTHORS = 7;
    static final int QUIT = 8;
    static final int LOAD_DATA =99;  //For testing only


}

/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/

package DataStructuresAssignment;

/**
 *
 * @author cjberry
 * This class is responsible for storing and displaying the attributes
 * of a Paper
 */
public class Paper implements Comparable {
    // Complete this

    private String title;

    public void setTitle(String atitle){
        this.title = atitle;
    }
    
    public int compareTo(Object o) {
        String newTitle = (String)o;
        return compareTo(newTitle);
    }

}

package DataStructuresAssignment;

/**
 * This class provides the framework for the DocumentListApplication. You need
 * to complete the methods to add, display, remove etc. papers and authors.
 * @author Jane
 */
import java.io.IOException;

public class DocumentListApplication {
    
    

    public DocumentListApplication() throws IOException {
        DocumentListUserInterface myDLA = new DocumentListUserInterface();
        while (myDLA.getAction() != ActionCodes.QUIT) {
            myDLA.displayTextInterface();
            switch (myDLA.getAction()) {

                case ActionCodes.ADD_PAPER: {   //Add a paper
                    
                    // complete
                    break;
                }
                case ActionCodes.DISPLAY_PAPER: {  // Display a paper
                    //complete
                    break;
                }
                case ActionCodes.DELETE_PAPER: {
                    //complete
                    break;
                }
                case ActionCodes.ADD_AUTHOR: {
                    //complete
                    break;
                }
                case ActionCodes.REMOVE_AUTHOR: {
                    //complete
                    break;
                }
                case ActionCodes.LIST_PAPERS: {
                    //complete
                    break;
                }
                case ActionCodes.LIST_AUTHORS: {
                    //complete
                    new Author().compareTo(this);
                    break;
                }
                case ActionCodes.LOAD_DATA: {
                    new LoadTestData().loadData(this);

                }
            }
        }
    }

    /**
     * Adds a paper to the list
     * @param aPaper paper to be added
     * @param anAuthor author to be added
     * @return true = added, false = not added
     */
    public boolean addAPaper(Paper aPaper, Author anAuthor) {
        // complete this
        return true; // change this
    }

    /**
     * Displays paper(s) that match title
     * @param title of the paper(s) to be displayed
     * @return true = paper found, false = paper not found
     */
    public boolean displayPapers(String title) {
        // complete this
        return true; // change this
    }

    /**
     * Deletes paper(s) that match title
     * @param title of the paper(s) to be displayed
     * @return the number of papers deleted
     */
    public int deleteAPaper(String title) {
        // complete this
        return 0; // change this
    }

    /**
     * Adds an author
     * @param aPaper  paper that the author is to be added to
     * @param anAuthor author to be added
     * @return true if author added, otherwise false
     */
    public boolean addAnAuthor(Paper aPaper, Author anAuthor) {
        // complete this
        
        
        return true; // change this
    }

    /**
     * Removes an author
     * @param aPaper  paper that the author is to be removed from
     * @param anAuthor author to be removed
     * @return true if author removed, otherwise false
     */
    public boolean removeAnAuthor(Paper aPaper, Author anAuthor) {
        // complete this
        return true; // change this
    }

    public void listPapers() {
        // complete this
    }

    public void listAuthors() {
        // complete this
    }
}

package DataStructuresAssignment;

/**
 * This class is responsible for generating the menu display for the
 * documentList Application. It also gets the keyboard input.
 * Keyboard input is saved in the member variables.
 * You need to change the getAllPaperDetails() and getAuthorDetails() methods
 * to match your implementation of Author and Paper. You may also need to change
 * other methods in this class, depending upon your particular approach to the
 * work.
 * @author cjberry
 */
import java.util.Scanner;
import java.io.*;

public class DocumentListUserInterface {

    /**
     * Stores keyboard input related to the paper to be added/displayed etc.
     */
    private Paper paperDetails;
    /**
     * Stores keyboard input related to the author to be added/displayed etc.
     */
    private Author authorDetails;
    /**
     * Stores code that indicates the action to be carried out.
     */
    private int action = 0;
    Scanner scan = new Scanner(System.in);

    public DocumentListUserInterface() {
        this.action = 0;
        authorDetails = new Author();
        paperDetails = new Paper();
    }

    /**
     * Calls displayMenu(), gets keyboard input, saves input in member variables
     * @throws IOException
     */
    public void displayTextInterface() throws IOException {
        this.action = displayMenu();
        switch (this.action) {
            case ActionCodes.ADD_PAPER: {    //Add a paper
                this.paperDetails = getAllPaperDetails();
                this.authorDetails = getAuthorDetails();
                break;
            }
            case ActionCodes.DISPLAY_PAPER: // Display a paper
            case ActionCodes.DELETE_PAPER: { //delete a Paper
                String title = getADetail("Enter title: ");
                paperDetails.setTitle(title);
                break;
            }
            case ActionCodes.ADD_AUTHOR:
            case ActionCodes.REMOVE_AUTHOR: { //Remove Author
                this.authorDetails = getAuthorDetails();
                break;
            }
            case ActionCodes.LIST_PAPERS: {
                break;
            }
            case ActionCodes.LIST_AUTHORS: {
                break;
            }
            case ActionCodes.LOAD_DATA:{ // For testing only
                break;
            }
        }
    }

    /**
     * Displays the main menu and returns action code.
     * @return a code that represents the action to be taken
     * @throws IOException
     */
    private int displayMenu() throws IOException {
        String input = null;
        int menuInput = -1;
        System.out.print(ActionCodes.ADD_PAPER + ". Add a Paper\n"
                + ActionCodes.DISPLAY_PAPER + ". Display Paper details\n"
                + ActionCodes.DELETE_PAPER + ". Delete a Paper\n"
                + ActionCodes.ADD_AUTHOR + ". Add Author\n"
                + ActionCodes.REMOVE_AUTHOR + ". Remove Author\n"
                + ActionCodes.LIST_PAPERS + ". List Papers\n"
                + ActionCodes.LIST_AUTHORS + ". List Authors\n"
                + ActionCodes.QUIT + ". Quit\n"
                + "Enter choice: ");
        try {
            input = scan.nextLine().toUpperCase();
            menuInput = Integer.parseInt(input);
        } catch (NumberFormatException e) {
            System.out.println("Please enter a number in the range 1 -4");
        }
        return menuInput;
    }

    /**
     * Gets title and rating and creates a new Paper
     * You need to change this to match your implementation of Paper
     * @return a Paper object containing the input details
     * @throws IOException
     */
    private Paper getAllPaperDetails() throws IOException {
        Paper newPaper = new Paper();
        String name = getADetail("Enter - title");
        int rating = getANum("Enter rating");// You need to change this is match your
        // version of Paper
        return newPaper;
    }

    /**
     * Creates a new author, gets name and email address.
     * You need to change this to match your implementation of Author
     * @return a Paper object containing the input details
     * @throws IOException
     */
    private Author getAuthorDetails() throws IOException {
        String name = getADetail("Enter author name");
        String emailAddress = getADetail("Enter email address");
        Author newAuthor = new Author(); // You need to change this is match your
        // version of Author
        return newAuthor;
    }

    /**
     * Displays a prompt for some keyboard input, gets the input  and returns it.
     * @param prompt String to be displayed
     * @return Keyboard input
     * @throws IOException
     */
    private String getADetail(String prompt) throws IOException {
        String paperName;
        System.out.println(prompt + " : ");
        paperName = scan.nextLine();
        return paperName;
    }

    /**
     * Displays a prompt for some keyboard input, gets the input  and returns it
     * as an integer. Catches non integer input and prompts again.
     * @param prompt String to be displayed
     * @return Keyboard input as an integer
     * @throws IOException
     */
    private int getANum(String prompt) throws IOException {

        String sNumber = "";
        int number = 0;

        while (sNumber.length() == 0) {
            System.out.print(prompt + " ");
            try {
                sNumber = scan.nextLine();
                number = Integer.parseInt(sNumber);
            } catch (NumberFormatException e) {
                System.out.println("Please enter digits only");
                sNumber = "";
            }
        }
        return number;
    }

    public int getAction() {
        return action;
    }

    public Paper getPaperDetails() {
        return paperDetails;
    }
}

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package DataStructuresAssignment;

/**
 *
 * @author cjberry
 */
public class Author implements Comparable{
    String authorName;

    public int compareTo(Object o) {
        String name = (String)o;
        return compareTo(authorName);
    }


}

package DataStructuresAssignment;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * @author Jane
 */
import java.util.Scanner;
import java.io.*;

public class LoadTestData {

    /**
     * Loads data for testing
     * @param myDLA Current DLA into which data is loaded.
     * @throws IOException
     */
    public void loadData(DocumentListApplication myDLA) throws IOException {

        Scanner pFile, lineScan;
        String entry, title = null, name = null, email = null;
        String sRating = null;
        int rating = 0;
        Paper newPaper = new Paper();
        Author newAuthor = new Author();

        System.out.println("Loading data");
        // read file person.txt and create new instance of person for each one
        final String resourcesPath = "resources/papers.txt";
        InputStream in = this.getClass().getResourceAsStream(resourcesPath);
        pFile = new Scanner(in);
        //     pFile = new Scanner(new File("papers.txt"));
        while (pFile.hasNext()) {
            entry = pFile.nextLine();
            lineScan = new Scanner(entry);
            while (lineScan.hasNext()) {
                title = lineScan.next();
                sRating = lineScan.next();
                rating = Integer.parseInt(sRating);
                name = lineScan.next();
                email = lineScan.next();
            }
            //   newPaper = (); Amend this to match your implementation
            //   newAuthor = (); Amend this to match your implementation
            myDLA.addAPaper(newPaper, newAuthor);
            System.out.println(title + " Added");
        }
    }
}