Questions tagged [design-patterns]
A design pattern is a general reusable solution to a commonly occurring problem in software design.
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Requests and handling requests
For this task, I don't think that the Observer Pattern can be used in its classic form. Those who have received the requests and those who choose to accept the request are not the same group. Those ...
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Specification pattern vs Always valid domain model [closed]
Let's say we have two aggregates:
...
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Inheriting from a JSON converter class with schema definition through constructor
I wanted to convert C++ data structures to JSON with little code. More specifically, I wanted to convert C++ data structures to nlohmann JSON representation.
Project context: The goal is to use this ...
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Two different JavaScript implementations of the observer pattern using class inheritance and concatenative inheritance
To practice design patterns and JavaScript, I'm implementing the observer pattern in two different ways:
One implementation using class inheritance
And another implementation using concatenative ...
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Simultanous states in a state machine
In Dungeons and Dragons, we have many spells, e.g. the Charm spell to get anyone to do what you want, the Web spell to entangle someone, the Invisibility spell to make yourself invisible (but once you ...
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Implementation of Strategy Pattern for Task Scheduler
I need to implement a feature that schedules notifications to a user to which a Task has been assigned. The schedule could be one-time or on a ...
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Is this a valid implementation of Memento Pattern in C#?
I've been studying design patterns from GOF for a few weeks, especially in C#, and I'm struggling with Memento Pattern. I know there are a lot of C# implementations on the web, but I came up with my ...
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Adapter pattern apply with JsonObject
The purpose of the code is to apply adapter pattern to put an extra feature for searching through json object.
I hate deep nested json object because it makes my code look messy when access through ...
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c++ general feedback on a custom performance oriented array
Introduction
I have written a first iteration of a 3d rendering-program utilizing openGL and c++ and i am looking to get some of my code reviewed.
As i am self-taught and have never received any input ...
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Decorator Pattern with member functions
Motivation: without SaveDecorator, we would have to write:
...
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Number partitioning: how to allow both 'light' and 'heavy' output?
I am working on a library for algorithms for multiway number partitioning.
One challenge I face is that some users need the entire partition, while other users need only the sums of the parts. For ...
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Is using State Pattern with nullptr states by default a good idea?
The following code uses a State Pattern with the states as pointers in a tuple instead of objects because many such states would not apply to people (e.g. HasSecretCrushState).
So the pointers are ...
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Another Vending Machine implementing State Pattern
I previously asked for a review for a Vending Machine implementing State Pattern in this linked post.
And received an answer from @radarbob. The code below is my revised attempt based on some of @...
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Vending Machine implementing State Pattern
I was asked to implement a Vending Machine in a recent interview coding challenge. My attempt at a solution is based on the state pattern.
I would like to get some code reviews on this bearing in mind ...
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Exporting a merged dataset from multiple source to a downloadable link
I'm working on a use case in hobby project where I am merging data from an external data source with an internal one and exporting that to a downloadable file
The use case is exposed in an ...
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Command design pattern for RPG prototype
I'm writing an assistant for the tabletop RPG Pathfinder in Java. I already have a few building blocks and decided to make a small side-project to play around the Command pattern. I know that there ...
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Pattern for people relations
Consider the following code. I'm trying to figure out a proper pattern and this is the best I can think of so far. The strange part is the transition from storing "people seen" to "...
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Handling resource authorization in a service
Problem: My application is built upon clean architecture. I want to create a new instance of a class in my lower layer, but the class itself resides in an upper layer. The upper layer can depend on ...
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Memento Pattern between sister classes
The following is my usage of the Memento Pattern when one class uses the copy constructor of a sister class (a separate derived class of the base class) and wishes to revert to the previous class. ...
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Observer Design Pattern in C++ to model magazine subscriptions
My attempt at a observer design pattern (I know using namespace std isn't good). I'm very new to design patterns. Everything is inline with class definition. Please tell me if I'm doing anything wrong ...
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Finding and changing filenames of different media files (photos, videos)
My tool should eventually change all media files' names to one qualified format yyyymmdd_hhmmss [optional desc].xxx:
If it's an image, the date is taken from "Date Taken" property of the ...
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How to design planet class so that it is open for changes? [closed]
The task is to model a Solar system using OOP. The planets are orbiting and its needs to find distances between planets.
My approach is something like this.
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Image scraper using Dependecy Injection in Rust with generics
I'm writing a scraper that downloads images from a given subreddit. I'm new to Rust, and in the majority of my previous projects I was using C++ or Java, where it's easy to do Dependency Injection.
I ...
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Python - Temperature - descriptors with conversion
So I'm trying to understand the concept of descriptors and gathered some code together and made an exampel out of different sources. Like the offical documentation and StackOverflow answers. I'd hope ...
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Scraping online store and writing to database
I'm making a project that will scrape some online store for an item, gets the data and stores it in a remote database that I have, and also able to read the database and display the data on a ...
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Nop class which can get optimized away
I designed a class for debug builds which does not incur any overhead in release mode. A usecase is for example: I have a function and I want to count how often it is called. For this I could write ...
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Abstract Factory Pattern Implementation
I implemented the Abstract Factory design pattern as follows.
Concrete Implementation
...
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Using Factory Design Pattern in Rest Controller of Spring
I used factory design pattern to identify the service according to the enum that comes from the api uri as request param. Everything seems okay according to me but cannot be sure if I used it right.
<...
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Should I replace this request queue?
I just found myself hacking around the limitations of a backend that aborts highly concurrent transactions by queueing the requests using Solution A. I don't like this solution very much, and have a ...
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Using Factory Design Pattern in Spring [closed]
I organized the factory design pattern but I'm not sure if I used it right or wrong.
Here's my data model;
...
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.NET Repository Pattern
I'm currently in the process of defining some framework, one of the first things that I thought I could start with was defining some repository pattern/layer.
I generally wanted some input on it, ...
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Object Oriented Routing using Python's FastAPI
I created a BaseRoute class route handling.
The BaseRoute class takes the following parameters:
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Design a pattern using python
I want to print the below pattern
*
* *
* * *
* * * *
* * * * *
My logic written
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Using fluent builder pattern for generating pdf
I'm testing to use a fluent builder pattern for generating a pdf file using AbcPDF.
I've looked at several methods of accomplishing this and I'd be very glad to get some input on what I've written so ...
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Undo/Redo implementation using Memento pattern Javascript
Relatively new to the Design patterns, Generally my works are writing function for the needs.
But now i need to implement a undo redo functionality, so i just read about the different patterns which i ...
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Alert system for game or simulator
I am creating an alert system for a game/sim in C# that keeps track of negative actions performed by the user during a training exercise. There are preconfigured alerts that have data, such as UI text ...
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A proxy class as a generic replacement for getters and setters v2
Have you ever written proxy objects, instead of using a setter and a getter method? In that case, I'm interested in your opinion on the following design for a templated proxy.
This is a second version,...
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Sudoku sequence solver for non-standard constraints
This script is designed to help solve sequences in Sudoku puzzles with variant constraints (ex: Thermometer, Renban, etc.).
Summary
The user specifies the constraints they want applied as well as the ...
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Java database connection and DAO implementation feedback
First things first, I made a DatabaseConnection-class which connects to the database like so:
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Arcade Stacker Game - Core Logic
This is my first post here, so I apologize if anything is incorrect.
I have created an endless arcade stacker game (like the stacker games at the arcade, but when you hit the top the grid resets and ...
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PHP Class(es) for setting up DB adaptor
Not sure if I have gone over board with this or if I have even approached it correctly.
Basic I wanted to created classes which fulfilled the following:
Single class that can be used to create a ...
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What is the elegant way to merge collection of entities with a duplicate field?
I have the following entity, I am getting it in response of REST API.
class Account {
private String ownerId;
private List<String> coOwners;
}
REST ...
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Generic decorator inspired by functional programming
I made a generic decorator in C++20 with concept for specialization. The idea is to be able to define only one function in the decorator to decorate all functions in a class.
You may try it (it's a ...
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Refactor typescript long switch case that run different code in according to property value
I have a typescript function that executes an array of actions on a given string value. This is the code:
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Two sets of scripts for a Katamari Damacy-style game
I would like some feedback on trying to implement SOLID principles to my Katamari Damacy-style game, I have provided below the 'original' script which accomplished a variety of tasks, and then the '...
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Function pattern for running DB queries using pool or transaction
Take the following INSERT query. Using knex (JS) just for abstractions
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React Typescript Project Using Traditional OOP Patterns
I'm writing an app meant to have similar functionality to LucidChart - drawing shapes/diagrams. I'm using React with Typescript (Create React App) and am trying to follow OOP/polymorphic patterns I've ...
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VBA OOP design patterns: factory, constructor, returned interface
While working on my demo database manager app, I have coded a previously presented Storage Library. The structure of the library's code and employed design patterns partially follow that of the Secure ...
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