import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.atomic.AtomicInteger;
// User Class
class User {
private static final AtomicInteger idGenerator = new AtomicInteger(1);
private int id;
private String username;
private String email;
private int reputation;
public User(String username, String email) {
this.id = idGenerator.getAndIncrement();
this.username = username;
this.email = email;
this.reputation = 0;
}
public int getId() {
return id;
}
public String getUsername() {
return username;
}
public int getReputation() {
return reputation;
}
public void incrementReputation(int points) {
this.reputation += points;
}
}
// Tag Class
class Tag {
private static final AtomicInteger idGenerator = new AtomicInteger(1);
private int id;
private String name;
public Tag(String name) {
this.id = idGenerator.getAndIncrement();
this.name = name;
}
public String getName() {
return name;
}
}
// Comment Class
class Comment {
private static final AtomicInteger idGenerator = new AtomicInteger(1);
private int id;
private String content;
private User author;
private LocalDateTime creationDate;
public Comment(String content, User author) {
this.id = idGenerator.getAndIncrement();
this.content = content;
this.author = author;
this.creationDate = LocalDateTime.now();
}
}
// Vote Class
class Vote {
private User voter;
private int value; // +1 for upvote, -1 for downvote
public Vote(User voter, int value) {
this.voter = voter;
this.value = value;
}
public int getValue() {
return value;
}
}
// Answer Class
class Answer {
private static final AtomicInteger idGenerator = new AtomicInteger(1);
private int id;
private String content;
private User author;
private List<Comment> comments;
private int votes;
private LocalDateTime creationDate;
public Answer(String content, User author) {
this.id = idGenerator.getAndIncrement();
this.content = content;
this.author = author;
this.comments = new ArrayList<>();
this.votes = 0;
this.creationDate = LocalDateTime.now();
}
public void addComment(Comment comment) {
comments.add(comment);
}
public void addVote(Vote vote) {
votes += vote.getValue();
}
}
// Question Class
class Question {
private static final AtomicInteger idGenerator = new AtomicInteger(1);
private int id;
private String title;
private String content;
private User author;
private List<Answer> answers;
private List<Comment> comments;
private List<Tag> tags;
private int votes;
private LocalDateTime creationDate;
public Question(String title, String content, User author) {
this.id = idGenerator.getAndIncrement();
this.title = title;
this.content = content;
this.author = author;
this.answers = new ArrayList<>();
this.comments = new ArrayList<>();
this.tags = new ArrayList<>();
this.votes = 0;
this.creationDate = LocalDateTime.now();
}
public void addAnswer(Answer answer) {
answers.add(answer);
}
public void addComment(Comment comment) {
comments.add(comment);
}
public void addVote(Vote vote) {
votes += vote.getValue();
}
public void addTag(Tag tag) {
tags.add(tag);
}
public List<Answer> getAnswers() {
return answers;
}
}
// StackOverflow Class
class StackOverflow {
private List<User> users;
private List<Question> questions;
public StackOverflow() {
this.users = new ArrayList<>();
this.questions = new ArrayList<>();
}
public User createUser(String username, String email) {
User user = new User(username, email);
users.add(user);
return user;
}
public Question postQuestion(String title, String content, User author) {
Question question = new Question(title, content, author);
questions.add(question);
return question;
}
public Answer postAnswer(String content, Question question, User author) {
Answer answer = new Answer(content, author);
question.addAnswer(answer);
return answer;
}
public List<Question> searchQuestionsByKeyword(String keyword) {
List<Question> result = new ArrayList<>();
for (Question q : questions) {
if (q.title.contains(keyword) || q.content.contains(keyword)) {
result.add(q);
}
}
return result;
}
}
// Demonstration Class
public class StackOverflowDemo {
public static void main(String[] args) {
StackOverflow stackOverflow = new StackOverflow();
User user1 = stackOverflow.createUser("JohnDoe", "john@example.com");
User user2 = stackOverflow.createUser("JaneDoe", "jane@example.com");
Question question = stackOverflow.postQuestion("How to learn Java?", "Can someone guide me on how to learn Java?", user1);
stackOverflow.postAnswer("Start with the basics and practice daily.", question, user2);
System.out.println("Question: " + question.title);
for (Answer answer : question.getAnswers()) {
System.out.println("Answer: " + answer.content);
}
System.out.println("User1 Questions:");
for (Question q : user1.getQuestions()) {
System.out.println(q.title);
}
System.out.println("User2 Answers:");
for (Answer a : user2.getAnswers()) {
System.out.println(a.content);
}
}
}
Sample Input and Output
Input:
Output:
Question: How to learn Java?
Answer: Start with the basics and practice daily.