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Java Java Data Structures - Retired Getting There Type Casting

Chaltu Oli
Chaltu Oli
4,915 Points
Posted by Chaltu Oli
Chaltu Oli
4,915 Points

I'm stuck on this one!!

I don't understand the challenge?

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;
  }
}
Coding Lab SFPL 4
Coding Lab SFPL 4
678 Points

It looks like the idea is to modify the String result = "" line in getTitleFromObject to return the title of the object passed into that method instead of returning an empty string.

1 Answer

Daniel Hartin
Daniel Hartin
18,106 Points
Daniel Hartin
Daniel Hartin
18,106 Points

The instructions aren't very clear but what it is asking you to do is to check the Object obj being passed in, if it of type String then cast it to a String and pass it back of is of type BlogPost then cast to BlogPost and return the title.

I've include some untested code below so don't read on if you want a go yourself

Hope this helps

Daniel

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;
    }else if(obj instanceof BlogPost){
    result = ((BlogPost) obj).getTitle();
  }

   return result;
}
}