Questions tagged [design-patterns]
For questions requesting extra attention to be paid to the usage of design patterns in the code.
1,414
questions
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26
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Print a hollow Rhombus [closed]
I am beginner in java, here is my code to print a hollow rhombus:
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3
votes
1
answer
83
views
Sequentially find the indexes of an element into a collection
Util class to find into a collection the indexes of a given element with multiple occurrences from the first index or relative to a given index.
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1
vote
2
answers
79
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Verification job with multiple type of batch verifiers
I have a use case where a verification batch job (non-generic) verifies domains based on its input e.g domain_type, batch_pointer etc. The verification handles it based on the domain type which uses ...
1
vote
1
answer
118
views
Business logic verification template
I have a use case of template design pattern with generics as mentioned below.
I have AbstractVerificationHandler that provides template for verification business ...
0
votes
0
answers
131
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Chain of Responsibility in the game of Hangman
I tried to do the Hangman Refactoring Kata for the piece of code over here - https://www.youtube.com/watch?v=-0MeoFTj6DU
This is how the initial code looks like after first set of refactorings (i.e. ...
1
vote
1
answer
103
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CPU emulator written in python (Adjustable Microcode!)
I've designed and implemented a CPU architecture in one day. Of key architectural details: Processor is supposed to support updatable microcode, Architecture extensions and Is designed to be ...
-3
votes
1
answer
219
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Design a set to classes to report battery/power status of different Alexa devices
I was asked below quesion in Amazon sde2 low level design interview recently and I have shown below my solution during the interview. I was rejected in this round.
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1
vote
1
answer
89
views
Implement saga pattern with Kafka
There are very few example on how to implement saga pattern with Kafka so I tried to come up with my own implementation choreography saga pattern using Kafka. I need to implement outbox pattern as ...
1
vote
1
answer
178
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Mouse and keyboard event system
I wrote a mouse and keyboard event system in C++, using the GLFW library to get mouse and keyboard states.
I've been working on a 3D game engine of my own for a long time (about 9 months) and wanted ...
1
vote
1
answer
84
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A Model View Controller Pattern implementation. Do I get it right?
I know there has been many questions on the Model-View-Controller pattern, but this question is a follow up on a previous question I asked regarding the implementation of a download manager:
Get files ...
5
votes
2
answers
127
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Get files downloaded asynchronously after double clicking on list item (C++)
The problem I am trying to solve as an exercise is as follows:
I have a UI running in the main thread, specifically a list view with many items. Each item represents a file that the user can download....
4
votes
3
answers
1k
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Python Enum Strategy Pattern
I have two behaviours: pulling or cloning a git repository.
It started as an Enum, but then I had to switch over the enum all the time.
I wanted to turn it into some kind of strategy pattern and ...
1
vote
1
answer
84
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Improved Component-Entity-System Using C++
Introduction
I am a newbie, so please take me easy :). I am writing a low-level game engine using C++, GLFW and also OpenGL. This is a continuation of Entity Component System Using C++ I've
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2
votes
1
answer
304
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Model-View-Presenter (MVP) pattern implementation
To learn more about design patterns, particularly the Model-View-Presenter (MVP) pattern, I am currently creating a CLI weight tracker application in Python. I would like you to review the code to ...
2
votes
1
answer
163
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Entity Component System Using C++
Introduction
I'm a new to C++ so please take me easy :) I am currently working on a low-level game engine using C++, OpenGL, and GLFW; I've implemented the Event System and the Input Manager, which ...
3
votes
1
answer
163
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Improved Event System & InputManager Using C++
I am new to C++, so please take me easy. I want to make a low-level game engine only using C++, OpenGL and GLFW. This is a continuation of Event System using C++ ; I added the suggestions from there. ...
1
vote
0
answers
50
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Event System in C++ [duplicate]
I am excited to share that I have developed an event system in C++. I have always been passionate about programming and have long aspired to create a low-level game engine solely using C++, OpenGL, ...
3
votes
2
answers
2k
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Event System using C++
I am excited to share that I have developed an event system in C++. I have always been passionate about programming and have long aspired to create a low-level game engine solely using C++, OpenGL, ...
8
votes
1
answer
173
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Lightweight general-purpose graph library in C++
As a personal side project I started building a graph library in C++ (I know, very original). The code is open source, but for the purpose of this question I will provide the relevant details and the ...
3
votes
1
answer
123
views
Implementing The Decorator Design Pattern in C++
I recently tried to implement the decorator design pattern in C++. Here is the code in full:
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1
vote
1
answer
59
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Class handling file conversion and data manipulation archiving [h5py]
I am a physics PhD student who co-developped a python package for file conversion of standard file format used in Scanning Probe Microscopy (SPM) and archiving of data manipulation for tracability. If ...
0
votes
1
answer
95
views
Strategy Pattern Inside State Pattern
I'm making a fps game where I created a hierarchical state machine; the problem is the two types of movement (standing movement and crouching movement). They are very similar; the only difference is ...
1
vote
0
answers
711
views
MVVM using Python's tkinter
My task is to change the architecture of a previously written application to Model-View-ViewModel and use the Command pattern. It is written in Python 3.10.6 and uses the tkinter library for the GUI.
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2
votes
2
answers
101
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Python Logger Implementation
I have developed an implementation of a logger in Python. I know that Python already has a built-in logger, my goal with this is to get feedback and suggestions for improvement, particularly about ...
4
votes
1
answer
346
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Unit of Work & Repository Pattern - Injecting UoW into Repository Base
Description
I am implementing the Unit of Work & Repository Pattern with Dapper as my ORM and PostgreSQL as the relational database. I have seen examples of UoW where:
The UoW class creates an ...
4
votes
1
answer
603
views
Modern state machine
Based on previous examples and code submitted, I wrote this simple state machine, let me know if you have other suggests on optimizations potentially algorithmic.
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2
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1
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99
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Modern chain of responsibility design pattern
Based on this question, I tried to simplify the use case with simpler model,
Let me know if you have other suggests on optimizations potentially algorithmic.
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2
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3
answers
96
views
Chain of Responsibility Pattern using std::any
The following code has a Handler class that follows the classic Chain of Responsibility pattern. But we don't want to write a new handler class for every new type ...
1
vote
2
answers
141
views
Replace personal names and addresses with company ones
The problem:
I am given a data frame. Somewhere in that dataframe there is 3*N
number of columns that I need to modify based on a condition. The
columns of interest look like this:
names_1
address_1
...
2
votes
1
answer
130
views
Saving entity containing complex jsonb column with validation and comparision
I've been a .NET Developer for almost 4 years. I'm stronly learning and trying using design patterns and following SOLID principles for 3 months right now (I know - a little late, but better late ...
4
votes
1
answer
326
views
Abstract base class for binary serialization
Ensuring that some logic is always being run before the user's overriding methods.
I'm writing a library and I have some abstract classes that can be binary serialized (and users can subclass them and ...
2
votes
1
answer
65
views
Composite and proxy pattern for multiclassing
A Multiclass is a CharacterClass that decided to add new CharacterClass types to combine with the original CharacterClass. These new CharacterClass types are ...
1
vote
1
answer
100
views
Prototype design pattern
As a practice and self-development exercise I have decided to implement design patterns in C#.
I am using polish cuisine as an example in my implementations. In this project I implemented Prototype ...
1
vote
1
answer
95
views
Singleton design pattern
as a practice and selfdevelopment exercise I have decided to implement design patterns in C#. I am using polish cuisine as an example in my implementations. In this project I implemented Singleton ...
3
votes
1
answer
77
views
Builder Pattern for factory creation of beings with different races
Races have many distinguishing physical characteristics. But apart from appearances, different races have other distinguishing characteristcs, all of I've decided to be built using the Builder ...
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1
answer
51
views
Replacing private helper methods with global functions in Python? [closed]
In Python there is no real notion of private access. It's merely suggested by social convention with _ prepended in method names.
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4
votes
2
answers
430
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Composite Pattern for putting on clothes
When putting on a piece of clothing, we need to check for any clothing that is already on the relevant body parts(s). The possible plural means that we should use the Composite Pattern for the body ...
1
vote
0
answers
40
views
Frontend to handle course planning and administration [closed]
I read up on and dived into the Repository pattern for a project I am working on.
I have understood that the repository abstracts the actual access to any form of storage for my data model. What I was ...
1
vote
1
answer
59
views
Chain of Responsibility pattern for updating coordinates of moving objects
PrimaryCoordinates are the coordinates in meters. SecondaryCoordinates are the coordinates in decimeters, with the origin ...
1
vote
0
answers
68
views
Check that inputs are valid dates
I have a method in a class that accepts either a datetime or string parameter. It is shown in the last code block (I didn't include the class). A little background is that I am defining a wrapper ...
1
vote
1
answer
951
views
How to transform the CompletableFuture response
Context: I have a client app which consumes an API. I want to call this API is async way (using java.net.http.HttpClient) and once I receive this data then I want ...
2
votes
1
answer
84
views
Build a message string depending on the type of signature of an invoice
The following method was meant to build a message depending on the type of signature of an invoice. It contains some if-else statements and code duplication.
The original method :
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4
votes
2
answers
201
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Automating the process of determining which boxes to load on each flight for freight company
I was given a test assignment for the interview of the company and below is the code that I shared with them. I developed it using .NET 6 (Core) Console application.
Actual problem statement:
Coding ...
4
votes
2
answers
142
views
Abstract Factory Implementation C#
I'm learning Factory pattern and I've implemented this simple example of an abstract factory. I've followed this video a little bit while writing this small example. Is there anything anti-pattern or ...
3
votes
1
answer
68
views
I made a webpage that simulates sharks eating fish in the torrid world of Wa-tor
I've been self-studying HTML/CSS/JS. I read about Wa-tor. It's a population dynamics simulation which simulates fish and sharks breeding and predating. This seemed cool so I decided to implement it....
0
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1
answer
129
views
Is this the correct way of implementing a builder pattern in C++?
Coming from a Javascript background, and just now getting into c++. Want to know if im doing the builder pattern correctly in C++, and also what could improve on ?
PongObject.cpp
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1
vote
1
answer
299
views
Creating complex object step by step
Builder pattern separates object construction from its representation
I have to generate username and password for the Account class. Since this operation is a bit ...
0
votes
1
answer
45
views
Nodejs Module Pattern And Caching
The question is about nodejs module pattern code structure.
My goal is to initialise the module at one time and export the module using module.export
so that, it's ...
1
vote
0
answers
34
views
How do you decide if a function should return data directly (via return statement) or indirectly (e.g. updating a class property) or both? [closed]
I have some functions which update records in some database tables.
When I run each function I want to know the number of records affected by each.
I'm wondering what the most elegant way of returning ...
2
votes
2
answers
339
views
Generic observable type
I am writing an observer design pattern that is not too complex but I still feel there's a lot for me to learn about C++ be it little details (especially coming from C).
A couple of observations:
I ...