चैट संदेश मॉडल का अभिकल्पन

public class Main {

  public static class User {
    private String id;
    private String username;

    public User(String id, String username) {
      this.id = id;
      this.username = username;
    }

    public String getId() {
      return id;
    }

    public void setId(String id) {
      this.id = id;
    }

    public String getUsername() {
      return username;
    }

    public void setUsername(String username) {
      this.username = username;
    }

    @Override
    public String toString() {
      return "User{id='" + id + "', username='" + username + "'}";
    }
  }

  public static void main(String[] args) {
    User user1 = new User("u101", "Alice");
    System.out.println(user1);
  }
}

import java.util.ArrayList;
import java.util.List;

public class Main {

  public static class ChatRoom {
    private String id;
    private String name;
    private List<String> memberIds; // Stores User IDs

    public ChatRoom(String id, String name) {
      this.id = id;
      this.name = name;
      this.memberIds = new ArrayList<>();
    }

    public String getId() {
      return id;
    }

    public void setId(String id) {
      this.id = id;
    }

    public String getName() {
      return name;
    }

    public void setName(String name) {
      this.name = name;
    }

    public List<String> getMemberIds() {
      return memberIds;
    }

    public void addMember(String userId) {
      if (!memberIds.contains(userId)) {
        memberIds.add(userId);
      }
    }

    @Override
    public String toString() {
      return "ChatRoom{id='" + id + "', name='" + name + "', members=" + memberIds + "}";
    }
  }

  public static void main(String[] args) {
    ChatRoom generalRoom = new ChatRoom("r201", "General Chat");
    generalRoom.addMember("u101"); // Alice's ID
    System.out.println(generalRoom);
  }
}

import java.time.LocalDateTime;

public class Main {

  public static class ChatMessage {
    private String id;
    private String senderId;
    private String roomId;
    private String content;
    private LocalDateTime timestamp;

    public ChatMessage(String id, String senderId, String roomId, String content) {
      this.id = id;
      this.senderId = senderId;
      this.roomId = roomId;
      this.content = content;
      this.timestamp = LocalDateTime.now(); // Set current time
    }

    public String getId() {
      return id;
    }

    public void setId(String id) {
      this.id = id;
    }

    public String getSenderId() {
      return senderId;
    }

    public void setSenderId(String senderId) {
      this.senderId = senderId;
    }

    public String getRoomId() {
      return roomId;
    }

    public void setRoomId(String roomId) {
      this.roomId = roomId;
    }

    public String getContent() {
      return content;
    }

    public void setContent(String content) {
      this.content = content;
    }

    public LocalDateTime getTimestamp() {
      return timestamp;
    }

    public void setTimestamp(LocalDateTime timestamp) {
      this.timestamp = timestamp;
    }

    @Override
    public String toString() {
      return "ChatMessage{id='" + id + "', senderId='" + senderId + "', roomId='" + roomId + "', content='" + content + "', timestamp=" + timestamp + "}";
    }
  }

  public static void main(String[] args) {
    ChatMessage msg = new ChatMessage("m301", "u101", "r201", "Hello, everyone!");
    System.out.println(msg);
  }
}