I'm loss don't know what to do

Question

I'm not sure if i should create a new instance of BlogPost first then create a object for obj and set post in the parameter or anything for that matter. this is frustrated

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;
     }

    return result;
  }
}

Answer 1 · 2015-10-01T00:49:25Z

October 1, 2015 12:49am

Hey Chevano,

Let's take a look. What you first want to do is to use the instanceof keyword just like the first step. Except this time we want to check if it is BlogPost.

Simply enough, we just do the following:

obj instanceof BlogPost

After we check if it's a BlogPost or not, we have to downcast the obj to a BlogPost object. Because we want to call the getTitle() method on the BlogPost object, it is a good idea to first store our downcasted BlogPost object as a variable. That way we can call it very easily. We can do that simply as follows:

BlogPost bp = (BlogPost) obj;

Now that we got our downcasted BlogPost variable, all we have to do is call the getTitle() method and then add it to our result string. We simply do this:

result += bp.getTitle();

I have posted my completed code as reference if needed:

public static String getTitleFromObject(Object obj) {
    // Fix this result variable to be the correct string.
    String result = "";
    if (obj instanceof String) {
      result += (String) obj;
    }
    if (obj instanceof BlogPost) {
      BlogPost bp = (BlogPost) obj;
      result += bp.getTitle();
    }
    return result;
  }
}

If this helped, don't forget to mark as best answer so others with the same question can see.

Happy coding and all the best,

Kevin

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chevano gordon

chevano gordon

I'm loss don't know what to do

1 Answer

Kevin Faust

Kevin Faust