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Java Java Data Structures - Retired Efficiency! Changing Course

Dominik Huber
Dominik Huber
4,631 Points

I'm stuck at the Video exercise. Please help me. Code inside.

Hi,

here is my implementation of the code.

I get several errors. I googled but can't find it. I'm stuck at the last task to change the video title in the Hash Map. But how can you change a key in a map?

Please help me :)

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.ArrayList;
import java.util.HashMap;

public class QuickFix {

  public void addForgottenVideo(Course course) {

    Video video = new Video("The Beginning Bits");
    List<Video> videoList = new ArrayList<Video>();

    videoList = course.getVideos();
    videoList.add(1, video);



    // 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) {

    for(Map.Entry<String, Video> entry : videosByTitle) {

     String title = entry.getKey();

      if(title.equals(oldTitle)) {

        Object obj = entry.remove(title);
        entry.put(newTitle, obj);

      }






    }



  }

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

    Map<String, Video> mapVideo = new HashMap<String, Video>();

    for(Video video: course.getVideos()) {

      mapVideo.put(video.getTitle(), video);

    }


    return mapVideo;


  }

}

2 Answers

Blake Larson
Blake Larson
13,014 Points

A couple things: You are calling the videosByTitle() method without any parameters and you can use the setTitle(newTitle) from the Video class. Try using videosByTitle(course). Find the oldTitle and the setTitle(newTitle)

Dominik Huber
Dominik Huber
4,631 Points

Thx for your input. I already solved it by looking up other threads in the forum. But here comes another question? How can I see the forum to the video? I just can find the forum AFTER I create my own thread. Any idea? I hope you know what I mean :P