Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Java Java Data Structures - Retired Efficiency! Changing Course

Juan Santiago
Juan Santiago
3,766 Points
Posted by Juan Santiago
Juan Santiago
3,766 Points

I'm lost in the final challenge :( I don't know how to import the video's title to the Map. Help!

In this step I'm asked to:

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.

Please, help D:

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;
import java.util.List;
import java.util.*;

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.
List<Video> videoList = course.getVideos();
    videoList.add(1, video);
  }

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

  }

  public Map<String, Video> videosByTitle(Course course) {
     Map<String, Video> sortedVideos = new TreeMap<String,Video>();
    for(Map.Entry<String,Video> entry :sortedVideos.entrySet()){
    String key = entry.getKey();
    Video value = entry.getValue();    
    }
    return sortedVideos;
  }

}

1 Answer

Dan Johnson
Dan Johnson
40,533 Points
Dan Johnson
Dan Johnson
40,533 Points

Since sortedVideos was just created with the no parameter constructor, it won't have any entries. In order to assemble it you'll want to use the video list from course.

Here's an outline:

public Map<String, Video> videosByTitle(Course course) {
  Map<String, Video> sortedVideos = new TreeMap<String,Video>();

  // For each video in the course:
    // Set the key to the video title, and the value as the video reference

  return sortedVideos;
}

You can use the put method for assigning key-value pairs.

Juan Santiago
Juan Santiago
3,766 Points
Juan Santiago
Juan Santiago
3,766 Points

Thank you for pointing me in the right direction, it took me like 4 hours but I complete the 2nd step xD

This was the final answer: 

public Map<String, Video> videosByTitle(Course course) {
     Map<String, Video> sortedVideos = new TreeMap<String,Video>();
    // For each video in the course:
    // Set the key to the video title, and the value as the video reference
    for(Video video: course.getVideos()) {
      sortedVideos.put(video.getTitle(),video);
    }
      return sortedVideos;
  }