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Java Java Data Structures - Retired Getting There Type Casting

Abe Daniels
PLUS
Abe Daniels
Courses Plus Student 2,781 Points

Not sure how to typecast the title from BlogPost

How would I go about typecasting the title from my BlogPost area?

com/example/BlogPost.java
package com.example;

import java.util.Date;

public class BlogPost {
    private String mAuthor;
    private String mTitle;
    private String mBody;
    private String mCategory;
    private Date mCreationDate;

    public BlogPost(String author, String title, String body, String category, Date creationDate) {
      mAuthor = author;
      mTitle = title;
      mBody = body;
      mCategory = category;
      mCreationDate = creationDate;
    }

    public String getAuthor() {
      return mAuthor;
    }

    public String getTitle() {
      return mTitle;
    }

    public String getBody() {
      return mBody;
    }

    public String getCategory() {
      return mCategory;
    }

    public Date getCreationDate() {
      return mCreationDate;
    }
}
TypeCastChecker.java
import com.example.BlogPost;

public class TypeCastChecker {
  /***************
  I have provided 2 hints for this challenge.
  Change `false` to `true` in one line below, then click the "Check work" button to see the hint.
  NOTE: You must set all the hints to false to complete the exercise.
  ****************/
  public static boolean HINT_1_ENABLED = false;
  public static boolean HINT_2_ENABLED = false;
  public static String result;
  public static String getTitleFromObject(Object obj) {
    // Fix this result variable to be the correct string.
    if (obj instanceof String) {
    String result = (String) obj;
    return result;
    }
    return result;
    if (obj instanceof BlogPost) {
      return BlogPost[1];
    }
  }
}

1 Answer

Ken Alger
STAFF
Ken Alger
Treehouse Teacher

Abe;

Casting can be a difficult concept to grasp indeed. In your TypeCastChecker.java you are returning a BlogPost when checking if obj is an instanceof BlogPost, and your getTitleFromObject is expecting a String returned. I am guessing that is where you want to do you casting and that then grab something that is a String to return.

You could do something along the lines of:

/* Code omitted for brevity */

if (obj instanceof BlogPost) {
          BlogPost bp = (BlogPost) obj;  /* casting */
          result = bp.getTitle();                /* grab the Title of the Blog Post */
}

return result;

It looks like you have multiple return statements as well. You can clean those up a bit and follow a skeleton of:

if (something happens here) {
       /* do something great */
       result = somethingGreat;
}

if (something else happens here) {
     /* do something awesome */
    result = somethingAwesome;
}

return result;

Hope it helps and post back if you are still stuck.

Happy coding,

Ken