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Start your free trialyas abi
58 PointsDo not know what is wrong with my answer
Hi Anyone know why this code is wrong?
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.Map;
import java.util.TreeSet;
import java.util.HashMap;
public class Blog {
List<BlogPost> mPosts;
public Blog(List<BlogPost> posts) {
mPosts = posts;
}
public List<BlogPost> getPosts() {
return mPosts;
}
public Map<String, Integer> getCategoryCounts(){
Map<String, Integer> allPosts = new HashMap<String, Integer>();
for( BlogPost Post : mPosts){
String category = Post.getCategory();
Integer count = allPosts.get(category);
if(count == null){
count = 0;
}
allPosts.put(category,count);
count++;
} return allPosts;
}
public Set<String> getAllAuthors() {
Set<String> authors = new TreeSet<>();
for (BlogPost post: mPosts) {
authors.add(post.getAuthor());
}
return authors;
}
}
1 Answer
Grigorij Schleifer
10,365 PointsHi yas, you have so many thing right and just a couple of snippents can be improved
Check the code below and let me know if we need to go over it together.
public Map<String,Integer> getCategoryCounts(){
// intialize the map as Hashmap
// no need to specify the Hashmap parameters again
Map<String,Integer> allPosts = new HashMap<>();
// iterate over all post in mPosts to obtain the categories for every post
// for every mPost you will check if there is a category available and store it in category
for(BlogPost Post : mPosts){ // I would choose a lower case name for the variables, it a convention thing ...
// fetch the category like you did
String category = Post.getCategory();
// if category is not in the HashMap, condition is true
if(allPosts.get(category) == null){
// create counter inside the loop and not before the loop creation
int counter = 0;
// map the category to the newly initialized counter
allPosts.put(category, counter);
}
// if the category alredy has a counter, we just fetch it from the map
int counter = allPosts.get(category);
// increment the category's counter inside the if statement
counter++;
// put it back into your map
allPosts.put(category, counter);
}
// when done iterating all of mPosts return
return categoryCounter;
}