The Single Responsibility Principle states that each module in a system should be responsible for a single feature or functionality, or aggregation of cohesive functionality. Another common way to put it is to say that each module should have only one reason to change.

learn more… | top users | synonyms (1)

57
votes
11answers
6k views

Does this class design violate the single responsibility principle?

Today I had an argument with someone. I was explaining the benefits of having a rich domain model as opposed to an anemic domain model. And I demoed my point with a simple class looking like that: ...
44
votes
7answers
10k views

Single Responsibility Principle - How Can I Avoid Code Fragmentation?

I'm working on a team where the team leader is a virulent advocate of SOLID development principles. However, he lacks a lot of experience in getting complex software out of the door. We have a ...
40
votes
7answers
5k views

How do I prove or disprove “god” objects are wrong?

Problem Summary: Long story short, I inherited a code base and a development team I am not allowed to replace and the use of God Objects is a big issue. Going forward, I want to have us re-factor ...
35
votes
8answers
4k views

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 ...
34
votes
11answers
5k views

Ensure that each class has only one responsibility, why?

According to Microsoft documentation, the Wikipedia SOLID principe article, or most IT architects we must ensure that each class has only one responsibility. I would like to know why, because if ...
21
votes
7answers
4k views

How to determine if a class meets the single responsibility principle?

The Single Responsibility Principle is based on the high cohesion principle. The difference between the two is that a highly cohesive classes features a set of responsibilities that are strongly ...
20
votes
10answers
3k views

Can/should the Single Responsibility Principle be applied to new code?

The principle is defined as modules having one reason to change. My question is, surely these reasons to change are not known until the code actually starts to change?? Pretty much every piece of code ...
19
votes
12answers
2k views

When does the “Do One Thing” paradigm become harmful?

For the sake of argument here's a sample function that prints contents of a given file line-by-line. Version 1: void printFile(const string & filePath) { fstream file(filePath, ios::in); ...
17
votes
6answers
2k views

Does multiple inheritance violate Single Responsibility Principle?

If you have a class which inherits from two distinct classes, does not this mean that your subclass automatically does (at least) 2 things, one from each superclass? I believe there is no difference ...
16
votes
5answers
1k views

Is SRP (Single Responsibility Principle) objective?

Consider two UI designers who want to design "user attractive" designs. "User attraction" is a concept that is not objective and only resides in the mind of designers. Thus designer A could for ...
15
votes
7answers
1k views

Should I refactor large functions that mostly consist of one regex? [closed]

I just wrote a function that spans approximately 100 lines. Hearing that, you are probably tempted to tell me about single responsibilities and urge me to refactor. This is my gut instinct as well, ...
14
votes
6answers
3k views

Is logging next to an implementation a SRP violation?

When thinking of agile software development and all the principles (SRP, OCP, ...) I ask myself how to treat logging. Is logging next to an implementation a SRP violation? I would say yes because ...
13
votes
4answers
1k views

How specific should the Single Responsibility pattern be for classes?

For example, suppose you have a console game program, which has all kinds of input/output methods to and from the console. Would it be smart to keep them all in a single inputOutput class or break ...
12
votes
5answers
797 views

How to avoid violating the SRP in a class to manage caching?

Note: The code sample is written in c#, but that shouldn't matter. I've put c# as a tag because I can't find a more appropiate one. This is about the code structure. I'm reading Clean Code and trying ...
12
votes
4answers
3k views

What is the difference between Single Responsibility Principle and Separation of Concerns

a)What is the difference between SRP and SoC? Perhaps that SRP is applied at class level, while SoC can be applied at system, subsystem, module, class or function levels. b) If answer to a) is yes, ...
11
votes
5answers
613 views

Code repetition vs multi responsible method

I try to follow the Single Responsibility Principle (SRP) and also to omit Code Repetitions. However there are often places where there are code repetitions that are nothing more than code blocks of ...
10
votes
6answers
1k views

Struggling with the Single Responsibility Principle

Consider this example: I have a website. It allows users to make posts (can be anything) and add tags that describe the post. In the code, I have two classes that represent the post and tags. Lets ...
10
votes
4answers
2k views

Is Domain Entity violating Single Responsibility Principle?

Single responsibility ( reason to change ) of an entity should be to uniquely identify itself, in other words, its responsibility is to be findable. Eric Evan's DDD book, pg. 93: most basic ...
10
votes
2answers
600 views

Single-responsibility and custom data types

In the past months I've asked for people here on SE and on other sites offer me some constructive criticism regarding my code. There's one thing that kept popping out almost every time and I still don'...
9
votes
2answers
537 views

Is there an “ask for only what you need” interface principle?

I have grown into using a principle for designing and consuming interfaces that says basically, "ask for only what you need." For instance, if I have a bunch of types that can be deleted, I'll make ...
9
votes
4answers
3k views

MVC: Does the Controller break the Single Responsibility Principle?

The Single Responsibility Principle states that "a class should have one reason the change". In the MVC pattern, the Controller's job is to mediate between the View and the Model. It offers an ...
9
votes
2answers
405 views

Too many CS files in a single project [duplicate]

I am working on a ‘brown-field’ project, with a team of programmers. I understand each programmer will have different styles. I am running into some criticism with my coding style, specifically ...
9
votes
3answers
3k views

IValidatableObject vs Single Responsibility

I like the extnesibility point of MVC, allowing view models to implement IValidatableObject, and add custom validation. I try to keep my Controllers lean, having this code be the only validation ...
9
votes
6answers
1k views

What are the practical ways to implement the SRP?

Simply what are the practical techniques people use to check if a class violates the single responsibility principle? I know that a class should have only one reason to change, but that sentence is ...
9
votes
3answers
304 views

How to manage single responsibility when the responsibility is shared?

I have base two classes, Operation and Trigger. Each has a number of subclasses which specialise in certain types of operations or triggers. A Trigger can trigger a specific Operation. Whilst an ...
9
votes
2answers
545 views

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 ...
8
votes
4answers
3k views

Is the Single Responsibility Principle applicable to functions?

According to Robert C. Martin, the SRP states that: There should never be more than one reason for a class to change. However, in his book Clean Code, chapter 3: Functions, he shows the ...
7
votes
3answers
492 views

Application of Single Responsibility Principle on a Button

I have a class that represents a button on the screen. This class has two methods: one for click event; the other for long-click event. Both events do different things. So, according to Single ...
7
votes
3answers
944 views

OO - are large classes acceptable? [duplicate]

Despite many years in IT, I still struggle with OO design. One particular problem I seem to keep ending up with is large classes, often containing many hundreds of lines of code. The OO world talks a ...
7
votes
2answers
257 views

Object reading from file, violation of SRP?

I am writing a physics simulation program in C++. I am a novice in OOP and C++. In my program, several objects need to be initialized based on data from an input file. For example, an imaginary ...
7
votes
1answer
182 views

Separation of Concerns when adding new types

I have a system I've been working on this week where I'm having a hard time balancing separation of concerns with easy extensibility. I'm adding new types to the system, and it feels like shotgun ...
6
votes
3answers
3k views

Should a method do one thing and be good at it? [duplicate]

"Extract Till You Drop" is someting I've read in Uncle Bob's blog, meaning that a method should do one thing alone be good at it. What is that one thing? When should you stop extracting methods? ...
6
votes
2answers
745 views

Is it good to have an interface plenty of methods which belong to different concepts, just to preserve the Liskov's Principle?

I'm currently studying a course based on Software Design and I had a discussion in class with my professor and some classmates about a problem represented by the next scenario: Scenario Imagine ...
6
votes
3answers
782 views

Do setters and getters always break the Single-Responsibility Principle?

As we know, The SRP states that every class should have single responsibility and that responsibility must be entirely encapsulated by the class. But setters and getters do serve another ...
6
votes
4answers
334 views

Class design dilemma: Encapsulation vs Single Responsibility/Separation of Concerns

I'm working on a class that represents an object with multiple representations - one is an XML type representation used by an automatic ordering system, the other is a POJO-based representation used ...
6
votes
2answers
196 views

Do I violate the Single Responsibility Principle with my multi-purpose AST Class?

I am writing a compiler, for which I devised a rather classic architecture: it's composed of sequential passes piped together, starting with a lexer and a parser, continuing with a macro processor, ...
6
votes
1answer
2k views

Standard practices for access control (design pattern)

I'm looking at my interface design and I am struggling to decide which is the most "correct" way to implement role-based access control, given a user and a subject that the user would like to access. ...
6
votes
3answers
210 views

How do I design a DAL when I have to deal with relationships?

Say I'm developing a bug tracker, where a ticket belongs to at most one milestone, and a milestone can have many tickets. When a milestone is deleted (from the database), all tickets associated with ...
5
votes
2answers
2k views

Difference between Single Source Of Truth and Single Responsibility Principle?

So I just found out about the term single source of truth while watching video series about programming code interviews. From what I understood it meant that the single source of truth is an ...
5
votes
2answers
358 views

Constructor Injection, Single Responsibility and List initialisation

Given the class: public class Foo : IFoo { private IBarRepository repository public Foo(IBarRepository repository) { this.repository = repository } public IList<IBar> Bars { ...
5
votes
4answers
970 views

Is this a Single Responsibility Principle violation?

I'm designing an OO graph library and at the moment I'm trying to figure out the design for a GraphEdge class. I've added setters and getters for it's nodes, direction and weight. This seemes ...
5
votes
3answers
725 views

Single Responsibility Principle Implementation

In my spare time, I've been designing a CMS in order to learn more about actual software design and architecture, etc. Going through the SOLID principles, I already notice that ideas like "MVC", "DRY"...
5
votes
1answer
87 views

How do I more effectively design this per its intended design while ensuring I'm meeting SOLID design principles?

I know what SRP is, but am questioning my current design of an object I call an entity. Below is a picture of the design I am referring to. If I shift the code from the GeometricInformation and ...
5
votes
2answers
207 views

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 oop-...
5
votes
2answers
402 views

Does increasing the number of classes increase code complexity? [duplicate]

To illustrate the question, let's say we have two programmers of comparable skill that both solve the same problem. The code they turn out has roughly the same lines of code, but one programmer uses 5 ...
4
votes
4answers
575 views

Are Compiler Directives an Antipattern?

I'm working on a legacy system that has a helper class that is symbolically linked into many different .Net projects within a solution. The logic is riddled with compiler directives that change it's ...
4
votes
2answers
287 views

What principle is violated by having a button do two radically different things or screens act radically different depending on the situation

I've come upon a situation several times in my career when previous developers have done something funny. They will make a control (button) function radically different depending on how the screen ...
4
votes
3answers
868 views

How is DRY principle ( applied at class level ) related to SRP?

In other words, is DRY (don't repeat yourself) applied at a class level a subset of SRP (single responsibilty principle)? What I mean is that while SRP states that each class should have only a ...
4
votes
5answers
606 views

Avoiding the Anaemic Domain - How to decide what single responsibility a class has

Even after reading a bunch I'm still falling into the same trap. I have a class, usually an enity. I need to implement more than one, similar operations on this type. It feels wrong to (seemingly ...
4
votes
2answers
352 views

Single responsibility vs procedural programming [duplicate]

Single responsibility (from SOLID) is like making me create classes with only one public method. But if it's so, it would be possible use static methods, and go back to procedural programming. What's ...