리포지토리 패턴

Python code

from abc import ABC, abstractmethod
from dataclasses import dataclass

@dataclass
class User:
    id: int
    name: str
    email: str

class UserRepository(ABC):
    @abstractmethod
    def find_by_id(self, user_id: int) -> User | None: ...
    @abstractmethod
    def find_all(self) -> list[User]: ...
    @abstractmethod
    def save(self, user: User) -> User: ...
    @abstractmethod
    def delete(self, user_id: int) -> bool: ...

class InMemoryUserRepository(UserRepository):
    def __init__(self):
        self._store: dict[int, User] = {}
        self._next_id = 1

    def find_by_id(self, user_id: int) -> User | None:
        return self._store.get(user_id)

    def find_all(self) -> list[User]:
        return list(self._store.values())

    def save(self, user: User) -> User:
        if user.id == 0:
            user = User(self._next_id, user.name, user.email)
            self._next_id += 1
        self._store[user.id] = user
        return user

    def delete(self, user_id: int) -> bool:
        return self._store.pop(user_id, None) is not None

# 비즈니스 로직은 추상 인터페이스에만 의존
def register_user(repo: UserRepository, name: str, email: str):
    user = repo.save(User(0, name, email))
    print(f"등록: {user}")
    return user

repo = InMemoryUserRepository()
register_user(repo, "Alice", "alice@test.com")
register_user(repo, "Bob", "bob@test.com")
print(f"전체: {repo.find_all()}")