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Java Java Data Structures - Retired Getting There Type Casting

Posted by Vashco Mukanangana
Vashco Mukanangana
34,487 Points

How do I return the results of the getTitle method and cast it to the BlogPost instance?

Challenge Task 2 of 2 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

Bummer: I expected the value from getTitle on the BlogPost instance, but instead I got ''
com/example/BlogPost.java TypeCastChecker.java import com.example.BlogPost; ā€‹ 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; } }

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;
  }
}
Gregorio Massara
Gregorio Massara
3,544 Points
Gregorio Massara
Gregorio Massara
3,544 Points

I think you need to add an else statement to cover the case of a BlogPost object passed as an argument of the getTitleFromObject function and then extract the getTitle() and then assign it to your result variable.

1 Answer

Gregorio Massara
Gregorio Massara
3,544 Points
Gregorio Massara
Gregorio Massara
3,544 Points

I think you need to add an else statement to cover the case of a BlogPost object passed as an argument of the getTitleFromObject function and then extract the getTitle() and then assign it to your result variable.

Vashco Mukanangana
Vashco Mukanangana
34,487 Points

Thank you Gregorio. Now I have an idea of what I need to do.