Java Java Data Structures Efficiency! Changing Course

Eshaa Dhall
Eshaa Dhall
Full Stack JavaScript Techdegree Student 13,122 Points

Need help with the ToDo 2nd for the Task 1 of Changing courses.

How add the new video created to the course as a second video?

com/example/model/Course.java
package com.example.model;

import java.util.List;

public class Course {
  private String mName;
  private List<Video> mVideos; 

  public Course(String name, List<Video> videos) {
    mName = name;
    mVideos = videos;
  }

  public String getName() {
    return mName;
  }

  public List<Video> getVideos() {
    return mVideos;
  }

}
com/example/model/Video.java
package com.example.model;

public class Video {
  private String mTitle;

  public Video(String title) {
    mTitle = title;
  }

  public String getTitle() {
    return mTitle;
  }

  public void setTitle(String title) {
    mTitle = title;
  }

}
QuickFix.java
import com.example.model.Course;
import com.example.model.Video;

import java.util.Map;

public class QuickFix {

  public void addForgottenVideo(Course course) {
    // TODO(1):  Create a new video called "The Beginning Bits"

    // TODO(2):  Add the newly created video to the course videos as the second video.

  }

  public void fixVideoTitle(Course course, String oldTitle, String newTitle) {

  }

  public Map<String, Video> videosByTitle(Course course) {
    return null;
  }

}

3 Answers

calp
calp
10,314 Points

The first thing you should do is import the List from java.util. Then you'll want to create a new Video object under the first TODO comment. After that you will need to create a list by getting it from the Course object that is passed in and then add to it. This works because when the Course object returns the List it is returning the reference to the variable. Here's my code for you to take a look at,

import com.example.model.Course;
import com.example.model.Video;

import java.util.Map;
import java.util.List;

public class QuickFix {

  public void addForgottenVideo(Course course) {
    // TODO(1):  Create a new video called "The Beginning Bits"
    Video v = new Video("The Beginning Bits");
    // TODO(2):  Add the newly created video to the course videos as the second video.
    List<Video> vids = course.getVideos();
    vids.add(1, v);
  }

  public void fixVideoTitle(Course course, String oldTitle, String newTitle) {

  }

  public Map<String, Video> videosByTitle(Course course) {
    return null;
  }

}
Grant Murphy
Grant Murphy
7,616 Points

I was misreading the second instructions as invoke a instance of course called videos and add the newly created video to that existing instance. Not simply add the new video to just the existing list.