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Java Java Data Structures - Retired Getting There Type Casting

Posted by Ankit Murarka
Ankit Murarka
1,054 Points

Didn't get what the question is asking.

I am trying to typecast the obj into BlogPost but now and again when I check my work, it says that the task1 has failed. I know I am doing something wrong, but don't know what.

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)
    {
      return (BlogPost) obj;
    }
    return result;
  }
}

1 Answer

orbyt
orbyt
10,358 Points

For the first question, you need to check if the Object being passed in is a String, and return it if so. This can be done like:

 if (obj instanceof String) {
      String result = (String) obj;
        return result;
    } else {
      String result = "";
        return result;
    }

The second part is very similar. If the object is not a String, cast it to a BlogPost, and call the getTitle() method on it, like so: 

 if (obj instanceof String) {
      String result = (String) obj;
        return result;
    } else {
      BlogPost bp = (BlogPost) obj;
        return bp.getTitle();
    }
Ankit Murarka
Ankit Murarka
1,054 Points

THanks I was trying something similar, but wasnt aware that I had to put it in an else block. I was putting it in the if block by changin the statement to:

if(obj instanceof BlogPost) :- this was failing task 1.

THanks !!

orbyt
orbyt
10,358 Points

np, be sure to mark this as answered if its resolved.