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Start your free trialGleb Ermolaev
1,029 PointsI cannot solve this challenge
Still cannot figure out where the mistake is. Compiler prints "For category Food expected 2, but recieved null".
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;
import java.util.Map;
import java.util.HashMap;
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 (BlogPost post: mPosts) {
authors.add(post.getAuthor());
}
return authors;
}
public Map<String, Integer> getCategoryCounts() {
Map<String, Integer> map = new HashMap<String, Integer>();
for (BlogPost post : mPosts) {
if (map.get(post.getCategory()) != null) {
map.put(post.getCategory(), map.get(post.getCategory() + 1));
} else {
map.put(post.getCategory(), 1);
}
}
return map;
}
}
1 Answer
andren
28,558 PointsThe issue is this line:
map.put(post.getCategory(), map.get(post.getCategory() + 1));
The + 1
is placed within the wrong parenthesis. With the way the code is written you ask ask map
to get the value post.getCategory() + 1
rather than asking it to get post.getCategory()
and then adding 1 to the value that is returned.
If you move the + 1
outside the parenthesis pair it is in like this:
map.put(post.getCategory(), map.get(post.getCategory()) +1);
Then your code will function as intended.
Gleb Ermolaev
1,029 PointsGleb Ermolaev
1,029 PointsThank you!