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Java Java Data Structures - Retired Getting There Type Casting

Daniel Maia
Daniel Maia
6,228 Points

Type Casting Understanding

I am struggling to understand how type casting works.

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;
      BlogPost blogpost = (result) new BlogPost(); 
    }

    return result;
  }
}

3 Answers

deckey
deckey
14,630 Points

Hi, every Object has 'toString' method which returns a string representation of the object. Try using that instead of typecasting String to obj.

Daniel Maia
Daniel Maia
6,228 Points

Go past the first part but now stuck on the second part when it asks me to the following:

The method getTitleFromObject will be called and passed a String and/or a com.example.BlogPost. For this first task, return the object obj type casted as a String if it is in fact a String.

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

Daniel Maia
Daniel Maia
6,228 Points

Ignoring from the code above BlogPost blogpost = (result) new BlogPost();

Go me through to part 2 of 2

how did you get past the first part

Janet Villarreal
Janet Villarreal
3,490 Points

From my understanding it changes the variable datatype to what you cast it to so they can "understand" each other