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Java Java Data Structures - Retired Exploring the Java Collection Framework Sets

Adarsh Cavale
Adarsh Cavale
2,262 Points

what is wrong with this?

what is wrong with this code? It seems right to me.

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

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


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

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

  public List<String> getExternalLinks() {
    List<String> links = new ArrayList<String>();
    for (String word : getWords()) {
      if (word.startsWith("http")) {
        links.add(word);
      }
    }
    return links;
  }

  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/Blog.java
package com.example;

import java.util.*;

public class Blog {
  List<BlogPost> mPosts;

  public Blog(List<BlogPost> posts) {
    mPosts = posts;
  }

  public List<BlogPost> getPosts() {
    return mPosts;
  }

  public Set<String> getAllAuthors() {
   Set<String> authors = new TreeSet<String>();
    for (BlogPost post : mPosts) {
     authors.add(post.getAuthor()); 
    }
  }
  return author;
}

1 Answer

Gabe Olesen
Gabe Olesen
1,606 Points

Hey Adarsh,

You did everything correct code wise, however there's a typo here:

return author; // needs to be return authors; 

Also here return statement out of scope:

public Set<String> getAllAuthors() {
   Set<String> authors = new TreeSet<String>();
    for (BlogPost post : mPosts) {
     authors.add(post.getAuthor()); 
    }
      //return authors; - Needs to be inside of the method but out of the For-Loop
  }
  return author;  // this return is outside of your getAllAuthors() scope 

Hope this helps!!!

~ Gabe :coffee: