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Java Java Data Structures Getting There Type Casting

Cory Walker
Cory Walker
6,037 Points

I really don't understand the assignment instructions, kind of lost, don't know what to do, any help would be appreciate

I really don't understand the assignment instructions, kind of lost, don't know what to do, any help would be appreciate

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 = "";
    return result;
  }
}

1 Answer

Manish Giri
Manish Giri
16,266 Points

There are two cases in this challenge, and both involve the type of (Object obj) -

  1. If the object passed in to the method is a String, you need to cast obj to a String and assign it to result, because you return result at the very end.
  2. Otherwise, if the object obj is an instance of BlogPost instead, you first cast it to a BlogPost object, then call the getTitle() method on this object to get it's string value, and assign it to result.

The instanceof operator would be handy.

Good luck!