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Java Java Data Structures Getting There Type Casting

I'm not sure what I'm supposed to be doing

The directions are:

"Now make sure that if a com.example. BlogPost is passed in for obj that you then cast it to a BlogPost. Return the results of the getTitle method on the newly type-casted BlogPost instance.

I've included BlogPost.java for your reference only"

I don't know what I'm to do.

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 getTitleFromObject(Object obj) {
    // Fix this result variable to be the correct string.
    String result = "";
    if (obj instanceof String) {
      result = (String) obj;
    }
    return result;

  }
}

1 Answer

Robert Stefanic
Robert Stefanic
35,170 Points

Hi Matt,

The challenge is asking you to return the result of getTitle (which is a method that BlogPost has). But you can't just call .getTitle() on the object -- you have to cast the obj into a BlogPost first because obj doesn't have a .getTitle() method.

So they want you to try casting the obj as a BlogPost first, and then running the .getTitle() method on the BlogPost object.

As a hint, you've already done some casting in your code! You're trying to cast the Object passed into the getTitleFromObject method into a String. Try casting it into a BlogPost instead!