Java Java Data Structures Efficiency! Changing Course

Anna Poff
Anna Poff
1,560 Points

I'm stuck in step 2 of this exercise!

Now I'd like to be able to get to the videos by their names, can you use the videosByTitle method to generate the proper map of title to video. We'll use it in the next step.

Where am I going wrong here? And what would be the proper way to correct it?

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"
Video video = new Video("The Beginning Bits"); 
    // TODO(2):  Add the newly created video to the course videos as the second video.
course.getVideos().add(1, video); 
  }

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

  }

  public Map<String, Video> videosByTitle(Course course) {
     for (Video video: course)  {

    return videosByTitle;
     }
  }

1 Answer

Manish Giri
Manish Giri
14,726 Points

Okay, so if you look in the Course class, you'll see that it has a List of Video objects. What the challenge wants you to do in that method is to loop through the list of videos using the course object passed to the videosByTitle method, and for each video in this list, you add to the Map - the title of the video, and the video object itself.

After the for loop, you return the Map itself.

The Course class has a getter method that you can use to retrieve the list of video objects from the course object, and the Video class has a getter method to return the title of the video object.

Give it a shot!