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Start your free trialChris Gauthier
Courses Plus Student 6,434 PointsUsing a treeset in java datastructure course
Can somebody please help me with this?
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;
}
}
package com.example;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
public class Blog {
List<BlogPost> mPosts;
public Blog(List<BlogPost> posts) {
mPosts = posts;
}
public List<BlogPost> getPosts() {
return mPosts;
}
Set<String> allAuthors = new TreeSet<> ();
for(BlogPost post : mPosts ){
allAuthors.add(post.getAuthor());
}
return allAuthors;
}
1 Answer
Mitchell Golden
4,804 PointsHello Chris, I see a couple of errors that are probably causing your issues. First, you're missing the method declaration for getAllAuthors(). Second, when you declared the Set<String> allAuthors, you need to add <String> after TreeSet. It should look like this:
public Set<String> getAllAuthors() { //<---this line was missing
Set<String> allAuthors = new TreeSet<String> (); // <--- the word "String" was missing from the brackets after TreeSet
for(BlogPost post : mPosts ){
allAuthors.add(post.getAuthor());
}
return allAuthors;
}