iP: Week 7

Refactor the code to extract out closely related code as classes.

• Minimal: Extract the following classes:
  • Ui: deals with interactions with the user
  • Storage: deals with loading tasks from the file and saving tasks in the file
  • Parser: deals with making sense of the user command
  • TaskList: contains the task list e.g., it has operations to add/delete tasks in the list

public class Duke {

    private Storage storage;
    private TaskList tasks;
    private Ui ui;

    public Duke(String filePath) {
        ui = new Ui();
        storage = new Storage(filePath);
        try {
            tasks = new TaskList(storage.load());
        } catch (DukeException e) {
            ui.showLoadingError();
            tasks = new TaskList();
        }
    }

    public void run() {
        //...
    }

    public static void main(String[] args) {
        new Duke("data/tasks.txt").run();
    }
}

• Stretch Goal: Consider extracting more classes. e.g., *Command classes (i.e., AddCommand, DeleteCommand, ExitCommand etc.) that inherits from an abstract Command class, so that you can write the main logic of the App as follows:

  public void run() {
      ui.showWelcome();
      boolean isExit = false;
      while (!isExit) {
          try {
              String fullCommand = ui.readCommand();
              ui.showLine(); // show the divider line ("_______")
              Command c = Parser.parse(fullCommand);
              c.execute(tasks, ui, storage);
              isExit = c.isExit();
          } catch (DukeException e) {
              ui.showError(e.getMessage());
          } finally {
              ui.showLine();
          }
      }
  }
  

  You can get some inspiration from how the code of the addressbook-level2 is organized.

Level 8. Dates and Times

Teach Duke to understand dates and times. For example, if the command is deadline return book /by 2/12/2019 1800, Duke understands 2/12/2019 1800 as 2nd of December 2019, 6pm, instead of storing it simply as a String.

• Minimal: Store deadline dates as a java.time.LocalDate in your task objects. Accept dates in a format such as yyyy-mm-dd format (e.g., 2019-10-15) and print in a different format such as MMM dd yyyy e.g., (Oct 15 2019).
• Stretch goal: Use dates and times in more meaningful ways. e.g., add a command to print deadlines/events occurring on a specific date.

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoUnit;

public class Main {
    public static void main(String[] args) {
        //create dates from strings
        LocalDate d1 = LocalDate.parse("2019-12-01");
        LocalDate d2 = LocalDate.parse("2019-12-02");
        LocalDate d3 = LocalDate.parse("2019-12-02");
        
        //compare dates
        System.out.println(d1.isBefore(d2)); // -> true
        System.out.println(d1.isAfter(d2)); // -> false
        System.out.println(d2.equals(d3)); // -> true
        
        //work with dates
        System.out.println(d1.getDayOfWeek()); // -> SUNDAY
        System.out.println(d1.getMonth()); // -> DECEMBER
        System.out.println(d1.plus(1, ChronoUnit.YEARS));  // -> 2020-12-01
        
        // get today's date and print it in a specific format
        LocalDate d4 = LocalDate.now();
        System.out.println(d4); // -> 2019-10-15
        System.out.println(d4.format(DateTimeFormatter.ofPattern("MMM d yyyy"))); // -> Oct 15 2019
    }
}

Level 9. Find

Give users a way to find a task by searching for a keyword.

Example:

find book
    ____________________________________________________________
     Here are the matching tasks in your list:
     1.[T][✓] read book
     2.[D][✓] return book (by: June 6th)
    ____________________________________________________________

Add JavaDoc comments to the code.

• Minimal: Add header comments to at least half of the non-private classes/methods.
• Stretch goal: Add header comments to all non-private classes/methods, and non-trivial private methods.