Reference library

System design patterns

Sharding, load balancing, CAP tradeoffs, and scaling patterns — interview and production ready.

3 matches

How to Build an Immutable Money Value Object in Python

Implement an immutable Money class with rounded decimal amounts, currency, safe equality, and hashing for use as a value object.

value-object immutability money

Python

class Money:
    def __init__(self, amount: float, currency: str):
        object.__setattr__(self, "_amount", round(amount, 2))
        object.__setattr__(self, "_currency", currency)

    def __setattr__(self, name, value):
        raise AttributeError(f"Money is immutable: cannot set '{name}'")

    def __delattr__…

13 0 Open

System design patterns medium

How to Implement the Abstract Factory Pattern in Python

Implements the Abstract Factory pattern to create families of related GUI objects (buttons, checkboxes) without specifying their concrete classes.

abstract-factory design-patterns system-design

Python

from abc import ABC, abstractmethod


class Button(ABC):
    @abstractmethod
    def render(self):
        pass


class Checkbox(ABC):
    @abstractmethod
    def render(self):
        pass


class WindowsButton(Button):
    def render(self):
        return "Rendering Windows-style button"


class WindowsCheckbox(Chec…

13 0 Open

System design patterns medium

How to Implement the Strategy Pattern in Python

This Python code demonstrates the Strategy design pattern using interchangeable sorting algorithms (bubble sort and quick sort) that can be swapped at runtime.

design-pattern strategy oop

Python

class SortingStrategy:
    def sort(self, data):
        raise NotImplementedError

class BubbleSort(SortingStrategy):
    def sort(self, data):
        result = data.copy()
        n = len(result)
        for i in range(n):
            for j in range(0, n - i - 1):
                if result[j] > result[j + 1]:
      …

13 0 Open

Browse by section

Each section groups closely related Python snippets.