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

dongji cui
dongji cui
2,464 Points
Posted by dongji cui
dongji cui
2,464 Points

why my code cannot work in this challenges 

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(BlogPost obj) {
    //BlogPost other = (BlogPost) obj;
    if (equals(obj)) {
      return 0;
    }
    return mCreationDate.compareTo(obj);//what I am supposed to write here?
  }

  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;
  }
}
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(BlogPost obj) {
    //BlogPost other = (BlogPost) obj;
    if (equals(obj)) {
      return 0;
    }
    return mCreationDate.compareTo(obj);
  }

  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;
  }
}

2 Answers

ISAIAH S
ISAIAH S
1,409 Points

You're supposed to write 'return mCreationDate.compareTo(obj.mCreationDate);'. And I think there's an error in this challenge which requires you to delete '//BlogPost other = (BlogPost) obj;'.

ISAIAH S
ISAIAH S
1,409 Points

Please mark my answer Best Answer.