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Java Java Data Structures Exploring the Java Collection Framework Sets

Sara Pasinato
Sara Pasinato
1,023 Points

How return a Set<String>list ??

The error displayed "Expected 5 authors, but received 0"

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.List;
import java.util.Arrays;
import java.util.Set;
import java.util.*;


public class Blog {
  List<BlogPost> mPosts;
  Set<String> allAuthor = new TreeSet<String>();

  public Set<String> getAllAuthors(){ 
    for (BlogPost post : mPosts) {
    allAuthor.addAll(post.getExternalLinks());

    }
     return allAuthor;
  }

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

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




}
Jacob Ludwig
Jacob Ludwig
2,065 Points

Why did you choose "getExternalLinks()"? Is there another getter that might be more appropriate? :)

2 Answers

Sara Pasinato
Sara Pasinato
1,023 Points

Yes, I have change it with getAthor() :) Like this:

public Set<String> getAllAuthors() {

  Set<String> authors = new TreeSet<>();

  for (BlogPost post: mPosts) {

        authors.add(post.getAuthor());
}
 return authors;}

and I've done:)