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Java Java Data Structures Getting There Type Casting

Quentin Grunenwald
seal-mask
.a{fill-rule:evenodd;}techdegree
Quentin Grunenwald
Python Web Development Techdegree Student 6,420 Points

How to modify result variable to accommodate for BlogPost parameter instead of String?

I keep getting compile time errors as I chose to declare different types of result variables, either as String or BlogPost, in order to fit with the parameter inputted. Is there another better and proper way to do this?

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

2 Answers

Hi Quentin,

Which error do you actually get? One confusing thing for me is that in TypeCastChecker you check if result is a instance of a BlogPost/String, but this variable doesn't exist at that time? Try to check for obj.

Please let me know if I misunderstood something or if that fixed the error!

With my best regards,

Philip

Quentin Grunenwald
seal-mask
.a{fill-rule:evenodd;}techdegree
Quentin Grunenwald
Python Web Development Techdegree Student 6,420 Points

Hi Philip,

Thanks for your answer. I figured it out, the mistake was that I was trying to cast the BlogPost object as a String instead of calling the method to get the String from the object itself.

All the best,

Quentin