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Java Java Data Structures - Retired Getting There Type Casting

sachin gupta
sachin gupta
2,553 Points
Posted by sachin gupta
sachin gupta
2,553 Points

need a little clarification of what is asked to do in this challenge?

i am not able to understand what is being asked in the challenge.. so need a little help with the requirement of the challenge...

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.

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

2 Answers

Geovanie Alvarez
Geovanie Alvarez
21,500 Points
Geovanie Alvarez
Geovanie Alvarez
21,500 Points

The second part if obj is isntance of BlogPost and casted the obj to BlogPost

public class TypeCastChecker {
    public static String getTitleFromObject(Object obj) {
        // Fix this result variable to be the correct string.
        String result = "";
        if(obj instanceof String){
          result = obj.toString();
        }

        if(obj instanceof BlogPost){ //>----- if obj is isntance of BlogPost
            result = ((BlogPost) obj).getTitle(); //<------- here obj is cast BlogPost
        }

        return result;
      }
}
Geovanie Alvarez
Geovanie Alvarez
21,500 Points
Geovanie Alvarez
Geovanie Alvarez
21,500 Points

The problem is you are returning before reach the variable

public static String getTitleFromObject(Object obj) {
    // Fix this result variable to be the correct string.

    if(obj instanceof String){
      return (String) obj; //<------ here
    }
    String result = obj.toString();
    return result;
  }

this is the way i do it

public static String getTitleFromObject(Object obj) {
    // Fix this result variable to be the correct string.
    String result = "";
    if(obj instanceof String){
      result = obj.toString();
    }
    return result;
  }
sachin gupta
sachin gupta
2,553 Points
sachin gupta
sachin gupta
2,553 Points

thank you for this suggestion it worked good... but i need help on the second part of the challenge... as am not able to understand what it demands.. it says,"Now make sure that if a com.example.BlogPost is passed in for obj that you then cast it to a BlogPost. Return the results of the getTitle method on the newly type-casted BlogPost instance. "