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Java Java Data Structures Getting There Type Casting

Jose Luis Jiménez Sastre
Jose Luis Jiménez Sastre
12,314 Points
Posted by Jose Luis Jiménez Sastre
Jose Luis Jiménez Sastre
12,314 Points

I don´t understand how cast in this challenge Task 2

I don´t know how cast to BlogPost an return getTitle method's value.

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

1 Answer

Tony Gemenie
Tony Gemenie
3,781 Points
Tony Gemenie
Tony Gemenie
3,781 Points

Hey Jose looks pretty good what worked for me was something like this:

java
//start of if looks good
if ...{
result = obj;
}
if ...{
result = (Object) obj;
}
return result;

The main thing is understanding inheritance. Craig created the String Object to use it with multiple types of variables you have to tell it what you're putting in. Good article Here should help you out.