Java Java Data Structures Organizing Data Comparable

name of the method?

what is the name of the method we should return?

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 int compareTo(Object o){
    BlogPost other = (BlogPost) o;
    if (equals(other)){
    return 0;
    return 1;
  public BlogPost(String author, String title, String body, String category, Date creationDate) {
    mAuthor = author;
    mTitle = title;
    mBody = body;
    mCategory = category;
    mCreationDate = creationDate;

  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;

1 Answer

Brendan Whiting
Brendan Whiting
Front End Web Development Treehouse Moderator 84,579 Points

So far, we're comparing the two objects and if they're the same, we return 0. Now we need to handle what happens if they're different objects.

Right now, we're just returning 1 always, but what they want is for you to compare the two objects by date. So what you can do is return a call to the compareTo method of the creation date field. This will return either a positive or negative number depending on which date is sooner, so if someone calls sort on a list of blog posts, it will order them by their date because compareTo has been implemented in this way.

Take a look at the previous video at 10:22 on line 27 for a similar example.