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Start your free trialGabriel E
8,916 PointsHow do I create a getAllAuthors method?
Hello,
On this challenge, I need to gather all the blogs, and order the authors alphabetically. I tried matching some of my code to it, but I don't quite understand how to do it. Could you please help? Thanks!
package com.example;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
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;
}
}
package com.example;
import java.util.List;
public class Blog {
Set<String> allAuthors = new TreeSet<String>();
allAuthors.addAll(blog.getAllAuthors());
List<BlogPost> mPosts;
public Blog(List<BlogPost> posts) {
mPosts = posts;
}
public List<BlogPost> getPosts() {
return mPosts;
}
}
1 Answer
Kristian Terziev
28,449 PointsYou create the needed method like that:
public Set<String> getAllAuthors() {
}
Then you need to loop through the posts with a foreach loop and save them in a Set. Therefore you need to create that set beforehand. You are also asked to make the set sorted, meaning you should use TreeSet:
Set<String> allAuthors = new TreeSet<String>();
for (BlogPost post : mPosts) {
allAuthors.add(post.getAuthor());
}
return allAuthors;
Of course for all that to work, you'll have to import both Set and Treeset:
import java.util.Set;
import java.util.TreeSet;
Gabriel E
8,916 PointsGabriel E
8,916 PointsThanks, but I still get a syntax error, because it says an enum is expected. Not sure what to do about this.
Gabriel E
8,916 PointsGabriel E
8,916 PointsThanks, but I still get a syntax error, because it says an enum is expected. Not sure what to do about this.
Kristian Terziev
28,449 PointsKristian Terziev
28,449 PointsCan you paste the error here, please?
Gabriel E
8,916 PointsGabriel E
8,916 PointsThanks i got it now!
Gabriel E
8,916 PointsGabriel E
8,916 PointsThanks i got it now!
Gabriel E
8,916 PointsGabriel E
8,916 PointsThanks i got it now!
Gabriel E
8,916 PointsGabriel E
8,916 PointsThanks i got it now!
Christian Lawrence
3,941 PointsChristian Lawrence
3,941 PointsHello,
I was doing this but with Lists and ArrayLists, it failed as it wanted to return a String. Does the ArrayList move the value to another object?