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Java Java Data Structures - Retired Exploring the Java Collection Framework Upgrade Comparable to use Generics

Posted by Ashmit Pathak
Ashmit Pathak
4,441 Points

i'cant understand what's going on

I'am repeatedly trying to solve this problem but I cant solve it plz tell me what's going wrong?????

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

import java.io.Serializable;
import java.util.Date;

public class BlogPost implements Comparable <BlogPost> , Serializable {
  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 int compareTo(Object obj) {

    if (equals(other)) {
      return 0;
    }
    return mCreationDate.compareTo(other.mCreationDate);
  }

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

  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

Paolo Bass
Paolo Bass
3,921 Points
Paolo Bass
Paolo Bass
3,921 Points

Hi Ashmit,

the compareTo() method must have a BlogPost rather than an Object in the parameter:

Also, you need to change the name of 'obj' to 'other'. I would also advise to use the getter method to access the mCreationDate variable.

public int compareTo(BlogPost other) {

if (equals(other)) {
  return 0;
}
return mCreationDate.compareTo(other.getCreationDate());

}