assistance with Create a method in Blog called getAllAuthors, Java Data Structures

Question

Hey there, I lost my work once when the console zonked out. Not the end of the world, but this time through I am having trouble still and on top of that I'm getting a mess of errors that seem inaccurate and I can't scroll through them or copy/paste to help. I'm certain I still have errors, but I'm not sure where to go next.

So basically, I know I don't have the right answer yet but also I'm not sure to what extent the workspace is functioning properly.

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.HashSet;
import java.util.List;
import java.util.TreeSet;

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<>();
  }
  for (Blog post : mPost) {
    allAuthors.add(post.getAuthor());
  }
}

Answer 1 · 2015-07-31T00:49:05Z

July 31, 2015 12:49am

Hmm. I finally found something that works from another person's post, but (and I feel silly) I know I couldn't walk it through for somebody else. If anyone comes across this and has a minute to add some explanation, I'd be grateful. Thanks!

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

Answer 2 · 2016-12-26T19:18:55Z

December 26, 2016 7:18pm

It will if you change the for statement.

for (BlogPost post : mPosts){}

Answer 3 · 2015-07-31T00:52:54Z

July 31, 2015 12:52am

You have an idea, let's fix the code

public Set<String> getAllAuthors() {
    Set<String> authors = new TreeSet<>(); // create a new set

  for (Blog post : mPosts) { // mPosts is the correct name
    authors .add(post.getAuthor());  // adds every author to the set
  }
  return authors; // return the set
}

This code fills a set of strings with all of the authors, the for each loop iterates al the posts contained in the list of post.

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Allison Hanna

Allison Hanna

assistance with Create a method in Blog called getAllAuthors, Java Data Structures

3 Answers

Allison Hanna

Allison Hanna

James Lambert

James Lambert

Enrique Munguía

Enrique Munguía

Dennis Van Laarhoven

Dennis Van Laarhoven