Managing Potluck Dinner Participants and Dishes in Java

Welcome to today's lesson, where we will tackle a common challenge in software engineering: the introduction of complex features while preserving backward compatibility. Our focus will be on a Potluck Dinner organization system, where we will manage participants and their respective dishes for each round. Get ready for an exciting journey through Java programming, step-by-step analysis, and strategic thinking. Let's dive into our adventure!

Initially, our Potluck Dinner organization system allows us to add and remove participants and manage their respective dishes for each round. There are three essential methods:

• boolean addParticipant(String memberId): This method adds a participant. If a participant with the given memberId already exists, it won't create a new one but will return false. Otherwise, it will add the member and return true.
• boolean removeParticipant(String memberId): This method removes a participant with the given memberId. If the participant exists, the system will remove them and return true. Otherwise, it will return false. When removing a participant, you need to remove their dish if they brought one.
• boolean addDish(String memberId, String dishName): This method enables each participant to add their dishes for every round. If a participant has already added a dish for this round OR if the memberId isn't valid, the method will return false. Otherwise, it will add the dish for the respective participant's round and return true.

Let's write our Java code, which implements the functions as per our initial state:

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

public class Potluck {
    private final Set<String> participants;
    private final Map<String, String> dishes;

    public Potluck() {
        participants = new HashSet<>();
        dishes = new HashMap<>();
    }

    public boolean addParticipant(String memberId) {
        if (participants.contains(memberId)) {
            return false;
        } else {
            participants.add(memberId);
            return true;
        }
    }

    public boolean removeParticipant(String memberId) {
        if (!participants.contains(memberId)) {
            return false;
        } else {
            participants.remove(memberId);
            dishes.remove(memberId);
            return true;
        }
    }

    public boolean addDish(String memberId, String dishName) {
        if (!participants.contains(memberId) || dishes.containsKey(memberId)) {
            return false;
        } else {
            dishes.put(memberId, dishName);
            return true;
        }
    }
}

In this code, we employed a Java HashSet to store unique participant IDs and a HashMap to store the participant's ID and their respective dish name. With this foundation laid, let's introduce some advanced functionalities.