Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Java Java Objects Delivering the MVP Forum

isaac schwartzman
isaac schwartzman
963 Points

I don't understand what it's asking

I don't really want the answer,though I wouldn't be opposed to one, I just don't understand what I'm supposed to construct.

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 String topicConstructor (Forum.java) {
  private String topic (Forum.java);{
System.out.printf(" %s", topic);
  }
    }
private String  topic (String title){

  public String topic(String title) {

 }
}

  /* 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

  public User(String firstName, String lastName) {
    // TODO: set and add the private fields

  }

  // TODO: add getters for firstName and 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 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);
    }
    /* Uncomment this when prompted
    Forum forum = new Forum("Java");
    // TODO: pass in the first name and last name that are in the args parameter
    User author = new User();
    // TODO: initialize the forum post with the user created above and a title and description of your choice
    ForumPost post = new ForumPost();
    forum.addPost(post);

// */
  }

}

3 Answers

Hi Isaac,

Let's see if I can help by breaking down each part of the question:

Add a constructor

  • i.e. add a special kind of method that doesn't have a specific return type and that will be called whenever we invoke a new instance of class 'Forum'

that accepts a String named topic

  • i.e. we'll need to pass in (String topic) as a parameter

to Forum.java.

  • i.e. this constructor will exist in the Forum.java file

Initialize the private field topic in the constructor to the value passed in.

  • i.e. inside the { } of the constructor, we'll need to make the 'private String topic' variable that you see at the top of the page equal to the value of the '(String topic)' that we passed to the constructor as a parameter. As you can see, there is a naming collision here (i.e. we can't put 'topic = topic' because the computer won't know which topic is which) - what special keyword can we use to represent the '(String topic)' that is passed in?

As a clue, you can do this in 3 lines of code, with the third line being a '}'

Hope that helps - let me know if not and I'll see if I can help further!

Michael

isaac schwartzman
isaac schwartzman
963 Points

my confusion is how to use forum.java

you don't need to use forum.java.

The task is asking you to 'add a constructor that accepts a String named topic TO Forum.java'. This just means that you need to type the constructor somewhere in the Forum.java file

Does that make sense?

isaac schwartzman
isaac schwartzman
963 Points

thanks for helping my confusion