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Start your free trialAshish Soni
2,320 PointsMap Objective
return map of category to count calculated by looping on all posts
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.Map;
import java.util.Set;
import java.util.HashMap;
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 (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 : getAllAuthors()) {
}
}
}
1 Answer
Simon Coates
28,694 PointsFor starters, you need to iterate over mPosts. The following seems to work:
package com.example;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
//new imports
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) {
//retrieve Integer value out of map for post.getCategory()
Integer count = map.get(post.getCategory());
//if no value, set to 0.
if(count == null) {
count = 0;
}
count += 1;
//put updated integer back into map.
map.put(post.getCategory(), count);
}
return map;
}
}
Ashish Soni
2,320 PointsAshish Soni
2,320 PointsHi Simon Coates, Thanks a lot for your solution.