Questions tagged [object-oriented]
A methodology that enables a system to be modeled as a set of objects that can be controlled and manipulated in a modular manner
3,433 questions
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Convenience inheritance
Sometimes, you inherit from a class that defines the semantics of your type (Shape – Ellipse – Circle). Other times, you inherit simply because it's convenient to do so.
A superclass may have ...
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Should I instantiate controllers in route modules or use static methods?
I’m building a modular REST API using Node.js + Express + TypeScript.
My controllers are defined as classes. In my route files, I currently create a new controller instance, like this:
import { Router ...
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Is it okay to mix OOP and modular approaches when building a backend with TypeScript/JavaScript?
I’m designing a backend in TypeScript (could also apply to JavaScript), and I’m wondering about the architectural approach.
Is it better to stick to a single paradigm (e.g., fully object-oriented or ...
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How to reduce the number of class instances passed to the __init__() method of a Python class?
I have a Python class called FunctionsManager; its __init__() method is the following:
class FunctionsManager:
def __init__(self, instance_class1, instance_class2, ..., instance_classN):
...
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OO design - Process that relies on the current state of objects
We have a CAD software extension, where you can draw products like walls, doors, windows, etc., and you can export the drawing as an order, which contains the parts and costs.
As part of this export, ...
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How far can you push Object Oriented Programming?
A getter is a failure to design an object. It violates encapsulation which is a core principle of object oriented programing.
Now please tell me, how do you design a libraries hash table collection ...
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Is it still a code smell if a class knows all subtypes but not using instanceof and downcasting?
According to Instanceof code smell, I know using "instanceof" is a code smell, so suppose there is a game with some Tools:
Tool.java:
public interface Tool{
public void printInfo();
}
...
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Is OOP really beneficial for enterprise-scale business software compared to procedural languages like ABAP or COBOL?
I'm currently drafting a Python coding standard for internal enterprise use, primarily targeting business applications that involve heavy data access, reporting, and transactional logic.
In this ...
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Should parameter names describe their object type?
I'm unsure whether parameter names should describe their object types or if shorter, more concise names are preferable.
Consider the following two method signatures:
public void PrintPoint(...
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Should setters silently sanitize input — or should they just throw? [closed]
Suppose the code's inside some FullName class
And suppose I want only capitalized name elements (let's ignore the fact that in some cultures, name elements may start with a lower-case letter)
Should I ...
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How to get rid of Mappers and make objects build themselves?
I am having a really hard time deciding where to instantiate my entities in the refactoring I am making. The project was built with DDD and it's layered: it has the infra, domain and app layers. In ...
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Should I expose an instance's state with methods?
I've read somewhere about a pattern that is as follows: if it'll change the state of the instance, the method should be named with a verb and return void; and if the method just returns something (...
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Avoiding throw because we are not sure the exceptions will always be caught
I'm a junior in my company, and one of the coding rules they have is:
"a constructor object must never fail" (i.e., never throw). So what if I give them an invalid parameter? Then, the ...
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When to *not* use SOLID principles
Coming from a math background, counterexamples are equally, if not more, helpful to me for understanding concepts than examples. I've seen many, many examples of when and how to use the SOLID ...
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Why do "protected variables" tend to violate open closed principle?
According to Why is Clean Code suggesting avoiding protected variables?, I know there are tons of reasons to avoid protected variables.
However, there is a reason at the currently highest voted answer ...
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How to organize struct-based "methods" in C similar to object-oriented style? [closed]
So I was coding in C for a while now, getting used to language syntax and different styles.
Implemented a couple of simple data structures, algorithms and tried my skills in making Minesweeper clone.
...
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Do I need to create an interface for every service class to follow good design principles?
I'm working on a custom Magento 2 module in my internship, and I'm trying to follow SOLID principles in my code.
Right now, my controller actions handle everything: getting request data, processing it,...
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Global State, How To Do IT?
im kind of a newbie so take me easy
i face a problem every time i make a project
specially Client projects, which is Global State i always struggle to do it
for example, here is the structure of one ...
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Is it the correct practice to keep more than 10 years old spaghetti legacy code untouched without refactoring at all in big product development?
I have been in two software product houses for three years in a row.
The first is a small company maintaining a fairly small management system with a monolithic legacy code base (almost twenty years). ...
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Why have private fields, isn't protected enough?
Is the visibility private of class fields/properties/attributes useful? In OOP, sooner or later, you are going to make a subclass of a class and in that case, it is good to understand and be able to ...
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How to structuring a read/write submodule in OOP Python
I am developing a python package that needs to be able to read/write from/to multiple formats. E.g. foo format and bar format. I am trying to contain the functions relating to each format in a single ...
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Shouldn't deep copy be the default, not shallow copy?
If you have an OO language, where every object always has a copy method, shouldn't that be deep copy by default?
In most languages I know, such a copy method is shallow, since a shallow copy is more ...
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Should we avoid object creation in Java?
I was told by a colleague that in Java object creation is the most expensive operation you could perform. So I can only conclude to create as few objects as possible.
This seems somewhat to defeat ...
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Is "avoid extra null pointer risk" a reason to avoid "introduce parameter objects"?
According to Should we avoid custom objects as parameters?, I know I can group related parameters to improve readability of the function, eg:
Original version:
public void showSchedule(long startDate,...
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Why is "hidden dependency" (required things not in parameter list directly) a disadvantage of "global variables", but not in "preserve whole object"?
According to https://softwareengineering.stackexchange.com/a/200092, as I know, "preserve whole object" is a refactor method that passes the whole object instead of required parameters only, ...
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Why use a special "Name" class (instead of just a string) for representing object names in C++?
Suppose we have an Instance class in a C++ program, which has a GUID/UUID, name, parents, children, and other properties which can be saved to or loaded from an XML file.
The intuitive approach for ...
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Why is "diamond problem" a problem? Why doesn't the child simply call both parent's methods sequentially? Why is a thing with solutions a problem?
I know there have been many post about diamond problem, one of it: Why do you reduce multiple inheritance to the diamond problem?. But I'm not asking what it is or what is the solution of the problem. ...
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In OOP, what counts as a "getter"
Note: I'm not looking for opinions on whether the authors of the article below are right or wrong. Mainly I'm looking for the exact definition of what they mean by getters, especially since I know ...
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Is it better to pass a specific “context” object to handlers rather than the entire domain object?
I’m designing a system where various “handlers” apply business rules to an object. Initially I had each handler receive the full domain object:
// A large domain object with many properties and ...
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In "avoid primitive obsession", what is the meaning of "make the domain model more explicit"?
According to When is primitive obsession not a code smell? and answer in https://softwareengineering.stackexchange.com/a/365205, I know one of the advantages of avoiding primitive obsession is "...
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Best way to add asynchronous execution for already implemented synchronous process
I have a complex process implemented in Java Spring microservice.
Currently this process is triggered on user request and it is synchronously executed.
This often results in a gateway timeout.
...
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C# var vs. interface vs. concrete class in object instantiation
As we know, there are (at least) four ways to instantiate a class object in C#. But I've never quite understood why some ways are better than others.
First of all, you can explicitly declare the ...
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What is the relationship between the terms "association", "aggregation", and "composition"?
I try to brush up on my technical interview skills as I plan to seek a better offer
I don't recall being ever asked that really, but I still want to clear up any confusion. What is association, ...
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When does encapsulating a primitive field into its own class make sense? [duplicate]
Let's say I have the following Java code:
public record Person(String firtName, String lastName, int age) {}
Can it makes sense to have instead:
public record Person(FirstName firtName, LastName ...
169
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Is it better to return NULL or empty values from functions/methods where the return value is not present?
I am looking for a recommendation here. I am struggling with whether it is better to return NULL or an empty value from a method when the return value is not present or cannot be determined.
Take ...
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If immutable objects are good, why do people keep creating mutable objects? [closed]
If immutable objects¹ are good, simple and offer benefits in concurrent programming why do programmers keep creating mutable objects²?
I have four years of experience in Java programming and as I see ...
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Why is "dependency injection" ok, but not "the opposite of preserve whole object (pass required parameters only)"?
According to Why should I use dependency injection?, "dependency injection" has some advantages, for example:
"Non dependency injection" version:
public class Client{
private ...
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How to "Tell, don't ask" when 2 objects involves in the condition and the decision at the same time?
According to Explanation on how "Tell, Don't Ask" is considered good OO, I know the following is bad:
if(a.isX){
a.doY();
}
public class A{
public boolean isX;
public void ...
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votes
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Why do we need private variables?
Why do we need private variables in classes?
Every book on programming I've read says this is a private variable, this is how you define it but stops there.
The wording of these explanations always ...
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What is the utility and advantage of getters & setters especially when they are merely used to read and assign values to properties of an object? [closed]
I’m still really new to learning to program. Just learning the syntax for a few programming languages at the moment.
The courses I viewed for C# and Java touched only very briefly on getters & ...
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Extracting type info
Suppose that I want to implement the following scenario.
There is a board and each board has a set of peripherals like leds, temp sensors, gpio and so on. Each of them implements the according C++ ...
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Passing info between different branches of a class hierarchy in C++?
So, I have a class hierarchy that looks like this:
It is an embedded project, so the entire code will be run over and over.
I have several algorithm classes, that compute some result given some inputs....
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Should business logic classes be POJO only?
I read about three-tier architecture and I have a question: I read that in business logic (that is, what is in logic tier) there should be POJO classes, but in most Spring manuals these classes are ...
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Refactoring a codebase from manual memory management to RAII
Edit: @Ben Cottrell's comment said this was similar to a question about spaghetti code. While both questions involve large codebases, mine addresses a specific technical pattern: manual memory ...
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How functional programming achieves "No runtime exceptions"
How does a functional programming language, such as Elm, achieve "No runtime exceptions"?
Coming from an OOP background, runtime exceptions have been part of whatever framework that is based ...
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What's the alternative to trying to inherit static methods?
I know you can't inherit static methods, and it seems the consensus is that if you feel like you need to, you're doing something wrong.
However, I don't know what the alternative is in my case. Please ...
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When are Getters and Setters Justified?
Getters and setters are often criticized as being not proper OO. On the other hand, most OO code I've seen has extensive getters and setters.
When are getters and setters justified? Do you try to ...
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Aggregation vs Composition
I understand what composition is in OOP, but I am not able to get a clear idea of what Aggregation is. Can someone explain?
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Why do many software developers violate the open/closed principle?
Why do many software developers violate the open/closed principle by modifying many things like renaming functions which will break the application after upgrading?
This question jumps to my head ...
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Should we eliminate local variables if we can?
For example, to keep a CPU on in Android, I can use code like this:
PowerManager powerManager = (PowerManager)getSystemService(POWER_SERVICE);
WakeLock wakeLock = powerManager.newWakeLock(...
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