Mnemonics for set of design principles: Single responsibility, Open-closed, Liskov substitution, Interface segregation, Dependency inversion

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C# Refactoring Code OOD and SOLID

C# Refactoring Code OOD and SOLID I’m having some questions regarding improvement of code structure and maintainability, especially regarding SOLID. These questions are specifically for this project, ...
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When applying the interface segregation, should you separate interfaces for regular setters and mathematical operations?

When applying the interface segregation, should you have separate interfaces for a straightforward setters and interfaces that perform an operation before setting? For example, say you have a class: ...
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How to use SOLID principles in this example

I have reading about SOLID principles last week and decided to try to solve real world problem by using them. So I got the problem of real world ecommerce site managing totals. Problem Statement: ...
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How do you keep up with 'requiring new methods in an interface' (Following LSP and adding new methods to interface seems to violate ISP)

I have a game that deals with opening and closing doors and the Door Engine deals with IDoor interface which has Open() and Close() contracts So far so good. the game is tested and works fine. Now a ...
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Private setters and getters

I am learning OOP - I have read this answer a number of times and now slowly start to understand some of the practical uses of public interfaces (getters and setters). I understand there is no need to ...
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Is Static a code-smell that is frequently bad? And if so, isn't AOP inherently smelly? [closed]

I'm working with my experience that static-anything is a code smell. Obviously static is a powerful and useful tool in our toolbox. But if I Ctrl+F static in a novice or sometimes even seasoned ...
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631 views

Gathering IP address and workstation information; does it belong in a state class?

I'm writing an enterprisey utility that collects exception information and writes to the Windows Event Log, sends an email, etc. This utility class will be used by all applications in the corporation: ...
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@Qualifier and Dependency Inversion Principle

I recently discovered SOLID principles and i'm trying to learn how to properly apply them. I have an application that had a huge interface: public interface NotificationService { public void ...
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9k views

What are the design principles that promote testable code? (designing testable code vs driving design through tests)

Most of the projects that I work on consider development and unit testing in isolation which makes writing unit tests at a later instance a nightmare. My objective is to keep testing in mind during ...
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Is this a violation of the Liskov Substitution Principle?

Say we have a list of Task entities, and a ProjectTask sub type. Tasks can be closed at any time, except ProjectTasks which cannot be closed once they have a status of Started. The UI should ensure ...
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Programming to an Interface and Interface Segregation in the Context of a User Class [duplicate]

I try to program to an interface whenever possible, but its not clear to me how I could apply it to a model as broad as a user. Which can hold many disparate fields (name, age, phone number, ssn, ...
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Programming to an Interface and Keep Testability in Unique Classes [duplicate]

I try to program to an interface whenever possible, but when I have a class that fulfills a very specific and unique purpose, one that can't be abstracted. Is it correct for me to say that I've ...
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Is the semantic contract of an interface (OOP) more informative than a function signature (FP)?

It is said by some that if you take SOLID principles to their extremes, you end up at functional programming. I agree with this article but I think that some semantics are lost in the transition from ...
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Is there a pattern to assist with working around or fixing violations of the Liskov Substitution Principle? [closed]

I've come across a rather large violation of the Liskov Substitution Principle in our codebase. There is an abstract class. Within it is an abstract method, implementers of which are expected to ...
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91 views

Architecture: Should I schema validate incoming reply messages?

A web service I consume uses XSD to describe its API. Recently, they added a field to a reply message where no xsd:any had been, so when our schema validator tried to validate against the previous ...
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3k views

What can go wrong if the Liskov substitution principle is violated?

I was following this highly voted question on possible violation of Liskov Substitution principle. I know what the Liskov Substitution principle is, but what is still not clear in my mind is what ...
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Provide part of context to class using interface

Currently I have class Context which I inject in some places in my code, like: protected override object GenerateSomething (object input, Context ctx) Depending on Context, Generate method gives ...
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Does test-driven development force me to follow SOLID?

I hear a lot from TDD practitioners that one of TDD's advantages is that it forces developers to follow SOLID principles (Single responsibility, Open-closed, Liskov substitution, Interface segregation ...
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Adding functionality to the activity (inheritance, decoration, strategy … ) or multiple inheritance

I cannot decide what approach should I use in the next situtation. One activity from my app need to have different functionality, here is the leak of multiple inheritence comes into play. ...
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Dependency inversion without static methods?

It's clear that the dependency inversion principle and the use of interfaces makes software components less coupled and promotes maintainability. On the other hand, these principles make using static ...
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When following SRP, how should I deal with validating and saving entities?

I've been reading Clean Code and various online articles about SOLID lately, and the more I read about it, the more I feel like I don't know anything. Let's say I'm building a web application using ...
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6answers
1k views

Are there flavours of OOP where some or all of the SOLID principles are antithetical to clean code?

I recently had a discussion with a friend of mine about OOP in video game development. I was explaining the architecture of one of my games which, to my friend's surprise, contained many small ...
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IOC Containers break OOP Principles

What is the purpose of IOC Containers? The combined reasons for it can be simplified to the following: When using OOP/SOLID Development principles, Dependency Injection gets messy. Either you have ...
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How to verify the Liskov substitution principle in an inheritance hierarchy?

Inspired by this answer: Liskov Substitution Principle requires that Preconditions cannot be strengthened in a subtype. Postconditions cannot be weakened in a subtype. Invariants ...
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Is it considered good practice to declare base interfaces without mutators, supplying mutatators in a sub-interface

I asked a question on StackOverflow on how to properly implement an ImmutableMap that abides by the SOLID principles. Due to Java's Map interface containing put and putAll, it violates the interface ...
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What is the meaning of “inversion” in Dependency Inversion design principle?

I'm reading about design patterns. I know what this principle does. High-level and low-level classes depend on abstractions. But why we say this is inversion?
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Is Dependency Inversion a valid alternative to the pImpl idiom?

If I want to present to the user of my code an interface, that is unlikely to change, I can write only the public part of the classes in public headers and have a single private pointer to another ...
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When NOT to apply Dependency Inversion?

I am currently trying to figure out SOLID. So Dependency inversion means that any two classes should communicate via interfaces, not directly. E.g. if class A has a method, that expects a pointer to ...
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Does merely parameterizing a dependency meet the requirements for Inversion of Control?

When I find a concrete dependency inside an extension method, I have been attempting to remove the (concrete) dependency by parameterising it like so // original implementation public static ...
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2k views

Is it good practice to declare and set properties in abstract classes?

I am using PHP and designing some abstract classes. I can declare properties with constant values within my abstract class and access/overwrite them from any class which extends this without re ...
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Is there a name for the problem of representing state twice and then getting out of sync? [closed]

I have a system that has configurable state values, like BoxCount, "Number of Visible Boxes on the screen". If I am using some heavyweight set of patterns (like MVC) that enforce the creation of ...
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397 views

How can I avoid tight coupling when practically every decision-logic has to check lots of distributed state?

As the senior developer in our company, I am currently starting to move our commercial php-mysql e-commerce solution (which takes data from a specific ERP-system) from procedural spaghetti-code which ...
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SOLID principles vs YAGNI

When do the SOLID principles become YAGNI? As programmers we make trade-offs all the time, between complexity, maintainability, time to build and so forth. Amongst others, two of the smartest ...
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Non-anemic model and SRP

I'm implementing a feature in legacy system right now. Instead of putting all my logic in some dummy application services and having anemic models, I thought I will try to do some OOP this time. I'm ...
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How to avoid “type dispatchers” when working with SOLID

I've realized that since I've been more and more strict about the SOLID principles, my code tends to consist of more pure data objects and a lot of "operator" classes which seems to go against ...
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Inheritance in imperative programming

My first introduction to programming was Java, which was horrible so I learnt Actionscript3 which was nice... "The point is" OOP was my introduction to programming where by I went on to gain a career ...
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281 views

Reducing dependency cycles and reducing coupling

I'm trying to learn how to produce quality object-oriented code and have been studying concepts like SOLID. I'm currently working on an entity-component-process system for a small game engine. ...
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DDD, modularizing the application and domain layers without breaking the DIP

Quoting DDD theory: The application layer is thin in terms of domain logic - it merely coordinates the domain layer objects to perform the actual work. When it comes to modularization, and ...
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Implementation Coupling

This question is regarding Interface Segregation Principle Best-Practices. I use abstract examples below, but the question arises from actual code I've seen that performs what I can only call ...
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Does this Decorator implementation violate the Liskov Substitution Principle?

Please consider the following implementation of the Decorator design pattern: WordBank objects store strings and return them to the client through the method getWords(). The decorator class, ...
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How to organize all classes derived from SRP?

As the SRP says, the way to achieve this principle is divide all into smaller. And what you have just made small, make more smaller. As consequence we got more files and my question is about it, how ...
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My first SOLID re-factoring

I am trying to make use of SOLID principles for the first time. I am re-factoring a File class that stores file information and makes file operations available. This class is then inherited to ...
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Dependency Inversion Principle

I have been studying also S.O.L.I.D. and watched this video: https://www.youtube.com/watch?v=huEEkx5P5Hs 01:45:30 into the video he talks about the Dependency Inversion Principle and I am scratching ...
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509 views

How do you apply Single Responsibility principle to a repository

I am trying to apply "SOLID" whenever I can and try to use common sense and avoid a pattern when I see that a pattern is creating more problems than it's trying to solve. I don't want to apply a ...
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What is the real responsibility of a class?

I keep wondering if it is legitimate to use verbs that are based on nouns in OOP. I came across this brilliant article, though I still disagree with the point it makes. To explain the problem a bit ...
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Extending a class for debugging: public API, hidden implementation or something else?

I'm working on a fairly large project that involves 3D drawing, and I want to add some visualizers (for example, to see the bounding boxes of the objects) to make debugging easier. However, I'm having ...
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Does having many duplicated methods and deep inheritance hierarchies in GUI APIs (Java Swing, Android SDK) violate the SOLID design principles?

For those unfamiliar with the SOLID principles you can start reading here: Wikipedia article. However, most of my understanding comes from: http://www.objectmentor.com/resources/publishedArticles.html ...
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LSP vs OCP / Liskov Substitution VS Open Close

I am trying to understand the SOLID principles of OOP and I've come to the conclusion that LSP and OCP have some similarities (if not to say more). the open/closed principle states "software ...
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Passing in config values to a method using SOLID principles

I have an email helper class that has a method that sends email: private static class EmailHelper { public static void SendEmail(string from, string to, string subject, string message) { ...
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Am I violating LSP if the condition can be checked?

This base class for some shapes I have in my game looks like this. Some of the shapes can be resized, some of them can not. private Shape shape; public virtual void SetSizeOfShape(int ...