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Java Java Objects Delivering the MVP Forum

Posted by Abhilasha jangid
Abhilasha jangid
2,925 Points

now I did not understand what it ask

Make sure you've added a new constructor to the ForumPost class that accepts a User named author, a String named title, and another String named description

Forum.java 
public class Forum {
  private String topic;

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

  public String getTopic() {
    return 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
   firstName = "Abhilasha";
   lastName ="Jangid"; 
  }

  // 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 class User{
     private String title;
  private String description;
   public User (String title,String description){
    this.title = title("wcbic");
    this.description =description("tukenth");
   }
  }

  }
}

2 Answers

Steve Hunter
Steve Hunter
57,712 Points
Steve Hunter
Steve Hunter
57,712 Points

Hi again,

There are three constructors to write in this challenge. There's one in User, another in Forum and one more in ForumPost.

All of these constructors take some parameters. These are variable that are passed into the method to set a member variable inside the class. None of these are hard coded using actual strings, names, topics or descriptions. Let's start with the Forum constructor as it is the most simple.

We have this:

public class Forum {
  private String topic;

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

The class has one member variable called topic. It is a String. The comment tells us that we want to set the value of this string from the constructor. That means the constructor will receive a string argument/parameter that we can use to do this. A constructor is usually public and always called the same as the class; we know this one receives a string which we'll call topic. Setting the member variable is done by using the this keyword. Putting all that together gives us:

public class Forum {
  private String topic;

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

The same process can be adopted for all the other constructor. See what the constructor is expecting to set inside the class (the member variables), make sure the constructor receives something of that datatype (User, String) etc. And then set the member variables inside the constructor.

I hope that helps - post your code for each constructor in here and we can work through them.

Steve.

Abhilasha jangid
Abhilasha jangid
2,925 Points
Abhilasha jangid
Abhilasha jangid
2,925 Points 
public class User{
  private String title;
  private String description;
    public User(String title, String description){
      this.description= description;
      this.title = title;
    }

whats wrong here

Steve Hunter
Steve Hunter
57,712 Points

Here, you've got mixed up between two classes.

This is the User class. A User has two member variables both of which are Strings. There's a firstName and a lastName.

What you've nearly created is the constructor for the ForumPost. That has a title, a description (both strings) but also a User called author. So, to edit your code slightly gives us the constructor for the ForumPost objects:

public class ForumPost {
  private User author;
  private String title;
  private String description;

  // TODO: add a constructor that accepts the author, title and description  
  public ForumPost(User author, String title, String description){
    this.author = author;
    this.title = title;
    this.description = description;
  }
 // rest omitted

Make sense?

Steve.