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Java Java Data Structures - Retired Getting There Type Casting

Help!

I need to complete this exercise to complete the stage. But I can't figure out the solution. I think spent too much time on trying to figure it out, haha.

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 return statement to be the correct string.
    if (obj instanceof String) {
      return (String) obj;
    }
    else {
      return (BlogPost) obj.getTitle();
    }
  }
}
Emmet Lowry
Emmet Lowry
10,196 Points

What are you being asked to do.

Awww... I forgot to attach the question:

The method getTitleFromObject will be called and passed a String and/or a com.example.BlogPost. Return the object type casted as a String if it is a String, and if it is the BlogPost type cast it, and return the results of the getTitle method.

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

Emmet Lowry
Emmet Lowry
10,196 Points

heres the code 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 return statement to be the correct string.

String title = "bad type";
  if(obj instanceof BlogPost) {
      BlogPost post = (BlogPost) obj;
     title = post.getTitle();

      }
  if(obj instanceof String) {
      title = (String) obj;

      }

  return title;

} }

hope this works

Worked great!

2 Answers

On this line:

else {
      return (BlogPost) obj.getTitle();
    }

you are casting your string from obj.getTitle() as a BlogPost object instead of leaving it as a string.

Try using this:

else {
      return ((BlogPost) obj).getTitle();
    }

This way, you are casting the obj variable instead of the obj.getTitle result.

Yep - I agree with Jason above. This post covers off the details of this, rather difficult, task.

Steve.