Java Java Data Structures Efficiency! Changing Course

Sahil Chawla
Sahil Chawla
5,834 Points

Error: Are you sure you updated the video title ?

public void fixVideoTitle(Course course, String oldTitle, String newTitle) { Map<String,Video> videosTitle = new HashMap<>(); videosTitle = videosByTitle(course); Video temp = videosTitle.remove(oldTitle); videosTitle.put(newTitle,temp);
}

Please let me know whats wrong in this.

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

import java.util.List;

public class Course {
  private String mName;
  public 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.ArrayList;
import java.util.HashMap;
import java.util.List;
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.mVideos.add(1, video);

  }

  public void fixVideoTitle(Course course, String oldTitle, String newTitle) {
    Map<String,Video> videosTitle = new HashMap<>();
    videosTitle = videosByTitle(course);
    Video temp = videosTitle.remove(oldTitle);
    videosTitle.put(newTitle,temp);    
  }

  public Map<String, Video> videosByTitle(Course course) {
    Map<String, Video> videosByTitle = new HashMap<>();
    List<Video> courseVideos = new ArrayList(course.getVideos());
    for ( Video video : courseVideos ) {
       videosByTitle.put(video.getTitle(),video);
      }

    return videosByTitle;
  }

}

1 Answer

andren
andren
28,384 Points

You have changed the mVideos field from private to public which is not something you were meant to do. The Course class has a getter method called getVideos(), getters are methods that are used to let other classes access private fields.

If you change mVideos back to being private in the Course class and simply replace mVideos with getVideos() in your code like this:

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);
}

Then your code will pass the first task.

Sahil Chawla
Sahil Chawla
5,834 Points

Hi Andren,

Thanks for your response, I got it working now. I wasn't actually changing the title of Video Object by using its setter method and yes i will change the private field of Course class to its original state and will use getters.