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Java Java Objects Delivering the MVP Forum

Don't know why this doesn't work.

I did what I thought should work, but now I'm getting tons of errors and the code "Forum forum = new Forum("Java");" Which I didn't even code, doesn't work also. Someone please help me!

Forum.java
public class Forum {
  private String topic;

  // TODO: add a constructor that accepts a topic and sets the private field topic
  public void setTopic(String topic) {
    topic = "";
  }

  public String getTopic() {
    return topic;
  }

  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 void User(String firstName, String lastName) {
    // TODO: set and add the private fields
    firstName = "";
    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 author;
  private String title;
  private String description;

  // TODO: add a constructor that accepts the author, title and description
  public void User(User author, String title, String description) {
    author = "";
    title = "";
    description = "";
  }

  public User getAuthor() {
    return author;
  }

  public String getTitle() {
    return title;
  }

  public String getDescription() {
    return 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(String getFirstName, String getLastName);
    // TODO: initialize the forum post with the user created above and a title and description of your choice
    ForumPost post = new ForumPost(getAuthor, getTitle, getDescription);
    forum.addPost(post);
  }

}
Brian Pedigo
Brian Pedigo
26,783 Points

Hi Matt after quickly looking over your code it seems that in your Forum class you made a setter method instead of constructor

   public void setTopic(String topic) {
    topic = "";
}  
//instead of the setter method make a constructor like

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

Also your ForumPost class's constructor was off:

public class ForumPost{
//constructor signature of this class should look like
public ForumPost(User author, String title, String description){
  this.authour = author;
  this.title = title;
  this.description = description;
}//end of constructor
}//end of class

Recheck your code for proper constructor creation. Remember constructors do not have a return type. There might be a few more errors but this should get you going in the right direction.

Kelvin Warui
Kelvin Warui
Courses Plus Student 878 Points

In your forum class you seem to be missing a constructor which should have a string argument .You are invoking the default constructor when your create an instance of forum and the error is caused when you try and pass the "java " string to it as the default constructor has no parameter .

1 Answer

See the replies from other students for more info. :)