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Java Java Data Structures Exploring the Java Collection Framework Sets

Adarsh Cavale
Adarsh Cavale
2,262 Points
Posted by 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
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: