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Java Java Objects (Retired) Delivering the MVP Wrapping up

A bug. I have added a constructor and it still asks if i have added it ?

public void setTopic(String topic) { mTopic = topic; }

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


  public User getAuthor() {
    return mAuthor;
  }

  public String getTitle() {
    return mTitle;
  }

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

  public User(String firstName, String lastName) {
    // TODO:  Set the private fields here
  }
}
Forum.java
public class Forum {
  private String mTopic;

  public String getTopic() {
      return mTopic;
  }

  public void setTopic(String topic) {
    mTopic = topic;
  }

  public void addPost(ForumPost post) {
      /* When all is ready uncomment this...
      System.out.printf("New post from %s %s about %s.\n",
                         post.getAuthor().getFirstName(),
                         post.getAuthor().getLastName(),
                         post.getTitle());
      */
  }
}
Example.java
public class Example {

  public static void main(String[] args) {
    System.out.println("Starting forum example...");
    if (args.length < 2) {
       System.out.println("first and last name are required. eg:  java Example Craig Dennis");
    }
    // Forum forum = new Forum("Java");
    // Take the first two elements passed args
    // User author = new User();
    // Add the author, title and description
    // ForumPost post = new ForumPost();
    // forum.addPost(post);
  }
}
Francisco Navarro
Francisco Navarro
14,185 Points

Hi Jery!

Could you say where exactly is the compiler warning you this?

3 Answers

Ken Alger
STAFF
Ken Alger
Treehouse Teacher

Jery;

I don't see a constructor in your Forum.java class. Generally constructors take the form of:

public ClassName() {}

The task is asking us to: We are currently in the process of building a Forum. There is some skeleton code here, but I need your help to finish it up. Let's do this! In the Forum class, add a constructor that takes a String for the topic and sets the private field mTopic.

Within the constructor we need to set mTopic=topic, assuming that topic is the name of the String variable we have assigned our constructor to accept. The code should look something like:

public Forum(String topic) {
   mTopic = topic;
}

Make sense?

Ken

why is it that the challenge will accept public Forum(String topic) but not public Topic(String topic)? why does the constructor have to be named "Forum"? cant it be named anything you want? Or to make a constructor you have to have the same name as the class for it to work(can i write " for it to be referenced (work)"?)?

public ForumPost(String topic) { mTopic = topic; }

Ken Alger
Ken Alger
Treehouse Teacher

Jery;

The challenge states to build the constructor inside the Forum.java class. Therefore our constructor needs to be in that class and have the format I mentioned above. I am not seeing the code you just posted in your original post, and specifically not in the Forum class.

Ken

Ken Alger
STAFF
Ken Alger
Treehouse Teacher

Bijan Fardjad

You raise a great question about constructor methods. A constructor in java is a special type of method that is used when an object is created (initialized). It is run when the object is created, constructing the object with default values for the object.

Rules for Creating Java Constructors

To keep it simple, there are two basic rules for constructors.

  1. The constructor name must be the same as it's class name.
  2. The constructor must have no explicit return type.

Types of Java Constructors

There are two types:

  1. Default constructor, which takes no arguments.
  2. Parameterized constructor, which, you guessed it, takes parameters.

Post back if you still have questions.

Happy coding,
Ken