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Java Java Objects Delivering the MVP Forum

Java Objects MVC Forum Challenge 4/4 - compiler "doesn't seem to see" args[0], args[1] .

Compiler "Are you sure you used the arguments passed in from the main method in Main.java(?)". I sure thought I did. I suppose I'm missing a detail or something - any help is greatly appreciated.

Forum.java
public class Forum {
  private String topic;
  // private String mTopic;
  private String firstName;
  private String lastName;    

  // TODO: add a constructor that accepts a topic and sets the private field topic
  public String getTopic() {
    return topic;
  }

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


  // Uncomment this when you are prompted to do so
  public void addPost(ForumPost post) {
    System.out.printf("A new post %s from %s %s about %s is available.\n",
            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
    this.firstName = firstName;
    this.lastName = lastName;
  }

  // TODO: add getters for firstName and lastName
  public String getFirstName() {
    return this.firstName; 
  }

  public String getLastName() {
      return this.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 ForumPost(User author, String title, String description) {
    this.author = author;
    this.title = title;
    this.description = 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(args[0], args[1]);
    // TODO: initialize the forum post with the user created above and a title and description of your choice
    ForumPost post = new ForumPost(author, "Title of the damn thing", "About some jibberish like C++");
    forum.addPost(post);

  }

}

3 Answers

After much head>desk, I just started the challenge over, this time I reverted to the "mConvention" convention while declaring variables and initializing them. Where I had previously mixed "m" with "this.", I simply stayed with the "m" convention. Using the exact same structure as before but being consistent with "m", the challenge passed first time. I think that this is a good example of sticking with known good conventions and being consistent throughout the code as a "best practice (agile)/best known method (Intel)". This is the Best Answer.

Brendan Whiting
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.a{fill-rule:evenodd;}techdegree seal-36
Brendan Whiting
Front End Web Development Techdegree Graduate 84,738 Points

I checked the Preview tab which showed me this output:

Beginning forum example
A new post null from Bob McBobberson about Title of the damn thing is available.

So it seemed that the firstName and lastName where getting assigned just fine, but something was wrong with the topic. The error message is misleading. So I went back to Forum.java and noticed that topic not getting assigned to the private property:

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

I changed it to this.topic = topic to make it clear we’re talking about the field as opposed to the argument being passed in, and this worked. Alternatively you could call the private field mTopic or something.

Brandon, thank you very much. Your suggestion did effect a change to the output:

Beginning forum example A new post Java from Bob McBobberson about Title of the blasted thing is available.

The topic problem is resolved, but it seems that Bob McBobberson may not be recognized as first and last names. Or perhaps that is misleading still. I'm going to work this until it's resolved, and I thank you for your help!

Still not working