Java Java Data Structures Efficiency! Changing Course

Damjan Vlaic
Damjan Vlaic
19,241 Points

---JAVA---

Can someone help me with this videosByTitle method? The task says:

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.

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.HashMap;
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) {

}

1 Answer

Yanuar Prakoso
Yanuar Prakoso
14,815 Points

Hi Damjan..

Great work on the first task. You even already imported the java.uti.HashMap package as preparation for the second task. Here the code you should use:

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

import java.util.HashMap;
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) {
//First you need to initialize new Map interface wrapped to HashMap class object:
   Map<String, Video>videosByTitle = new HashMap<>();

//Then since the Course object course is already passed as parameters, you can use it to get the List of Videos:
//Then you can iterate all available videos there:
  for(Video video : course.getVideos()) {//<--please note: in Course class getVideos method returns List<Video>
     //Then you can get the Title of each video using .getTitle() method in Video class
    //After that you can combine all into the videosByTitle map as Key (String), and Value (Video):
      videosByTitle.put(video.getTitle(), video);
  }
   return videosByTitle;//<-- finally we returns a HashMap of <String, Video>
}

I hope this can help a little

Damjan Vlaic
Damjan Vlaic
19,241 Points

it helped a lot, tnx for helping me :D