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Java Java Data Structures Organizing Data Comparable

Mehmet Arabaci
Mehmet Arabaci
4,432 Points
Posted by Mehmet Arabaci
Mehmet Arabaci
4,432 Points

Comparable task 2 of 3 help.

Hi in the Java Data Structures course within learn Java I'm stuck on task 2 of 3. The code I have:

  @Override
    public int compareTo(Object obj) {
        BlogPost temp = (BlogPost) obj;
        if (temp.equals(obj)) {
            return 0;

        }
        return 1;
    }

and I've seen this code on other forum posts but it was never explained well enough why it's not working and what needs to change. The error message that comes back is looks like task 1 is not working now. Task one was meant to return 1. Very confused!!

com/example/BlogPost.java 
package com.example;

import java.util.Date;

public class BlogPost implements Comparable {
  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;
  }

    @Override
    public int compareTo(Object obj) {
        BlogPost temp = (BlogPost) obj;
        if (obj.equals(temp)) {
            return  0;

        }
        return 1;
    }

  public String[] getWords() {
    return mBody.split("\\s+");
  }

  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;
  }
}

2 Answers

Trent Christofferson
Trent Christofferson
18,846 Points
Trent Christofferson
Trent Christofferson
18,846 Points

When you cast something you need to make sure it is of that type. Use an if statement using instance of to see if it is an instance of BlogPost

Mehmet Arabaci
Mehmet Arabaci
4,432 Points
Mehmet Arabaci
Mehmet Arabaci
4,432 Points

Okay I did that now but same error: "Oops! It looks like Task 1 is no longer passing." Task one was meant to return 1.

@Override
    public int compareTo(Object obj) {
        if (obj instanceof BlogPost) {
            BlogPost temp = (BlogPost) obj;
            if (temp.equals(obj)) {
                return 0;
            }
        }
        return 1;
    }