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Java Java Objects Delivering the MVP Forum

Shareef Nuseibeh
Shareef Nuseibeh
5,270 Points

Can't get through this exercise.

Main.java

public class Main {

public static void main(String[] args) { System.out.println("Beginning forum example"); if (args.length < 2) { System.out.println("Usage: java Main <first name> <last name>"); System.err.println("<first name> and <last name> are required"); System.exit(1); }

    Forum forum = new Forum("Java");
// TODO: pass in the first name and last name that are in the args parameter
User author = new User(args[0], args[1]);
// TODO: initialize the forum post with the user created above and a title and description of your choice
ForumPost post = new ForumPost(author, "title", "description");
forum.addPost(post);

}

}

Forum.java
public class Forum {
  private String topic;

  // TODO: add a constructor that accepts a topic and sets the private field topic

  public String getTopic() {
    return topic;
  }
public Forum(String topic) {
//set mTopic to the topic passed in to the constructor
mTopic = topic;
}

  /* Uncomment this when you are prompted to do so
  public void addPost(ForumPost post) {
    System.out.printf("A new post in %s topic from %s %s about %s is available",
            topic,
            post.getAuthor().getFirstName(),
            post.getAuthor().getLastName(),
            post.getTitle()
    );
  }
  */

}
User.java
public class User {
  // TODO: add private fields for firstName and lastName
  private String firstName;
  private String lastName;

  public User(String firstName, String lastName) {
    // TODO: set and add the private fields
    this.firstName = firstName;
    this.lastName = lastName;
  }

  // TODO: add getters for firstName and lastName
  public String getFirstName() {
    return firstName;  
  }

  public String getLastName() {
    return lastName;  
  }

}
ForumPost.java
public class ForumPost {
  private User mAuthor;
  private String mTitle;
  private String mDescription;

  public ForumPost(User author, String title, String description){
    mAuthor = author;
    mTitle = title;
    mDescription = description;
  } 

  public String getDescription() {
    return mDescription;
  }

  public User getAuthor() {
    return mAuthor;
  }

  public String getTitle() {
    return mTitle;
  }

  // TODO: We need to expose the description
}
Main.java
public class Main {

  public static void main(String[] args) {
    System.out.println("Beginning forum example");
    if (args.length < 2) {
      System.out.println("Usage: java Main <first name> <last name>");
      System.err.println("<first name> and <last name> are required");
      System.exit(1);
    }

        Forum forum = new Forum("Java");
    // TODO: pass in the first name and last name that are in the args parameter
    User author = new User(args[0], args[1]);
    // TODO: initialize the forum post with the user created above and a title and description of your choice
    ForumPost post = new ForumPost(author, "title", "description");
    forum.addPost(post);


  }

}

1 Answer

Emmanuel C
Emmanuel C
10,636 Points

The only thing I've noticed when trying to go through the challenge using your code, is that in the Forum.java constructor you assign the parameter to mTopic, which is never declared. I think you ment to assign it to your topic property, seeing as how its the same name as the argument you can use the this keyword to mean the property topic of the current instance, not the parameter.

public Forum(String topic) {
    this.topic = topic;
}