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Java Java Objects (Retired) Delivering the MVP Wrapping up

Marcus Schumacher
Marcus Schumacher
16,616 Points
Posted by Marcus Schumacher
Marcus Schumacher
16,616 Points

So close but need help :)

I don't see why the User.getLastName and get first name doesn't work here.

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

  //constructor
  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
}
User.java 
public class User {
  private String mFirstName;  
  private String mLastName;


  public User(String firstName, String lastName) {
    mFirstName = firstName;
    mLastName = lastName;
  }

  public String getFirstName() {
    return mFirstName; 
  }

  public String getLastName() {
    return mLastName; 
  }
}
Forum.java 
public class Forum {
  private String mTopic;
  private String topic;



  public String getTopic() {
      return mTopic;
  }

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

  public void addPost(ForumPost post) {

      System.out.printf("New post from %s %s about %s.\n",
                         User.getFirstName(),
                         User.getLastName(),
                         ForumPost.getDescription());

  }
}
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);
  }
}
Mark Miller
Mark Miller
45,831 Points
Mark Miller
Mark Miller
45,831 Points

I think you must create an object of type User and then you can invoke its getter methods for the first and last names. This is because the Forum class is not an inner, or nested, class inside the User class. If you were calling the methods from inside of the User class, then it would be okay to user User.getFirstName() as you have here. But you are calling the methods from outside the class, so an object must first be created before the method of that class can be used.

Also, the static keyword can be used to change the normal behavior, I think. That's why you've done that before. It was either inside of that class, or the static keyword had been declared, enabling the class to invoke its properties outside of the class declaration file.

https://en.wikibooks.org/wiki/Java_Programming/Keywords/static

http://docs.oracle.com/javase/tutorial/java/javaOO/classvars.html