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95
votes
12answers
39k views

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 ...
61
votes
13answers
6k views

Why is it a good idea for “lower” application layers not to be aware of “higher” ones?

In a typical (well-designed) MVC web app, the database is not aware of the model code, the model code is not aware of the controller code, and the controller code is not aware of the view code. (I ...
35
votes
8answers
5k views

What should be allowed inside getters and setters?

I got into an interesting internet argument about getter and setter methods and encapsulation. Someone said that all they should do is an assignment (setters) or a variable access (getters) to keep ...
27
votes
6answers
3k views

Using third-party libraries - always use a wrapper?

Most projects I am involved with use several open-source components. As a general principle, is it a good idea always to avoid binding all components of the code to the third-party libraries and ...
23
votes
4answers
1k views

Why Java doesn't make use of encapsulation with some classes?

My question is related with System.in and System.out classes (there might be others like those in the Standard library). Why is that? Isn't that a bad practice in OOP? Shouldn't it be used like: ...
20
votes
6answers
1k views

Should I place functions that are only used in one other function, within that function?

Specifically, I'm writing in JavaScript. Let's say my primary function is Function A. If Function A makes several calls to Function B, but Function B is not used anywhere else, then should I just ...
16
votes
9answers
1k views

Hiding away complexity with sub functions

I am having a discussion on code style, and it's starting to sound like a "matter of taste". I strongly believe otherwise, so I'm writing this to get your opinion and learn from your arguments for and ...
12
votes
6answers
1k views

Method chaining vs encapsulation

There is the classic OOP problem of method chaining vs "single-access-point" methods: main.getA().getB().getC().transmogrify(x, y) vs main.getA().transmogrifyMyC(x, y) The first seems to have ...
11
votes
4answers
855 views

Nested Classes: A useful tool or an encapsulation violation?

So I'm still on the fence as to whether or not I should be using these or not. I feel its an extreme violation of encapsulation, however I find that I am able to achieve some degree of encapsulation ...
11
votes
4answers
26k views

What is the use of Association, Aggregation and Composition (Encapsulation) in Classes

I have gone through lots of theories about what is encapsulation and the three techniques of implementing it, which are Association, Aggregation and Composition. What i found is, Encapsulation ...
10
votes
7answers
2k views

Is it bad code smell if private method calls public one?

Is it bad code smell to call public method in private method of same object instance?
10
votes
5answers
1k views

Can I use Dependency Injection without breaking Encapsulation?

Here is my Solution and projects: BookStore (solution) BookStore.Coupler (project) Bootstrapper.cs BookStore.Domain (project) CreateBookCommandValidator.cs CompositeValidator.cs IValidate.cs ...
9
votes
6answers
2k views

Why did Java make package access default?

I'm asking this question because I believe they did it for a very good reason and that most people do not use it properly, well from my experience in industry so far anyway. But if my theory is true ...
9
votes
3answers
684 views

Do I suffer from encapsulation overuse?

I have noticed something in my code in various projects that seems like code smell to me and something bad to do, but I can't deal with it. While trying to write "clean code" I tend to over-use ...
9
votes
5answers
345 views

How to make it obvious that a function is being accessed from the outside?

This is a C specific question. I am trying to keep everything possible inside the translation unit boundaries, exposing only a few functions through the .h file. That is, I am giving static linkage to ...
8
votes
5answers
547 views

How to TDD test that objects are being added to a collection if the collection is private?

Assume that I planned to write a class that worked something like this: public class GameCharacter { private Collection<CharacterEffect> _collection; public void Add(CharacterEffect e) ...
8
votes
2answers
443 views

Why shouldn't I make variables public, but should use public getters/setters? [duplicate]

I'm watching a C++ tutorial video. It is talking about variables inside classes and assert that variables should be marked private. It explains that if I want to use them publicly, I should do it ...
8
votes
1answer
969 views

JavaScript objects and Crockford's The Good Parts

I've been thinking quite a bit about how to do OOP in JS, especially when it comes to encapsulation and inheritance, recently. According to Crockford, classical is harmful because of new(), and both ...
7
votes
6answers
4k views

Are Get-Set methods a violation of Encapsulation? [duplicate]

Possible Duplicate: When are Getters and Setters Justified In an Object oriented framework, one believes there must be strict encapsulation. Hence, internal variables are not to be exposed ...
6
votes
4answers
2k views

Is JavaBeans a good example of encapsulation?

I'm trying to understand if JavaBeans is a good example of encapsulation. In my view, it's not as usually all the internal state is exposed through getters and setters. A simple example is public ...
6
votes
6answers
991 views

How is encapsulation used for safety?

I am learning OOP. I have studied much about encapsulation but the more I read the more I became confused. I understand we hide (by making private) data and expose it to user of class (other ...
5
votes
1answer
397 views

Is there a database programming language with encapsulation to prevent the injections?

One of things that annoys me about SQL is that it can't think in terms of objects and it's lack of encapsulation makes me constantly have to escape commands to prevent injections. I want a database ...
5
votes
3answers
1k views

How important is encapsulation? [duplicate]

As a student in programming, I learned that encapsulation is one of the most important principles of object-oriented programming. However, I only follow that principle when I feel like it suits my ...
5
votes
5answers
646 views

Should I always encapsulate an internal data structure entirely?

Please consider this class: class ClassA{ private Thing[] things; // stores data // stuff omitted public Thing[] getThings(){ return things; } } This class exposes the ...
5
votes
2answers
239 views

What defines an encapsulation properly?

I find the encapsulation concept a bit confusing. So far I have read that the members of the class should be private and any access to private members must be through getter and setter methods, which ...
5
votes
2answers
536 views

Modularity and “encapsulation” in C

This applies to C (and probably to any other similar non-object oriented language). If I have a central data store and potentially concurrent access there are two ways I can see of protecting it. ...
5
votes
2answers
446 views

Please explain object versioning in the nodejs module system

This question is about the persistance of variables across different modules in nodejs when they don't directly "require" each other, but do "require" a common ancestor. It is also the generalised ...
4
votes
4answers
587 views

Are trivial protected getters blatant overkill?

Something I really have not thought about before (AS3 syntax): private var m_obj:Object; protected function get obj():Object { return m_obj; } private var m_str:String; protected function get ...
4
votes
2answers
535 views

Why does Clojure neglect the uniform access principle?

My background is Ruby, C#, JavaScript and Java. And now I'm learning Clojure. What makes me feel uncomfortable about the later is that idiomatic Clojure seems to neglect the Uniform access principle ...
4
votes
4answers
320 views

Which language introduced the idea of private (hidden) variables? [duplicate]

I know C++ had private variables inside classes, and Java, C#, Javascript, and others picked up on that and ran with it. Aside from variable scope, most languages before that just made everything ...
4
votes
3answers
714 views

When too much encapsulation was reached

Recently, I read a lot of good articles about how to do good encapsulation. And when I say "good encapsulation", I am not talking about hiding private fields with public properties; I am talking about ...
4
votes
4answers
331 views

Encapsulate standard C functions?

While studying the C programming language and learning safe practices, I'm inclined to write a layer of functionality over several parts of the standard library. This would serve two purposes: I ...
4
votes
2answers
184 views

Is excessive indirection and/or redundant encapsulation a recognized concept? [closed]

I'm curious if there's a series of tendencies or anti-patterns when programming whereby a developer will always locally re-wrap external dependencies when consuming them. A slightly less vague ...
4
votes
1answer
69 views

Encapsulation: Should all properties be private and protected?

After learning about encapsulation in OOP, I started to use only protected and private properties, share data via accessors and change properties via mutators. Right now, I'm afraid of declaring ...
4
votes
1answer
156 views

Implementing a Username Class

I am attempting to encapsulate several features about a user in a single class. Although the main use for this class would be to initialize it once and never have to call set any variables again, I ...
3
votes
4answers
620 views

is 'protected' ever reasonable outside of virtual methods and destructors?

so, suppose you have some fields and methods marked protected (non-virtual). presumably, you did this because you didn't mark them public because you don't want some nincompoop to accidentally call ...
3
votes
4answers
593 views

How do you remember encapsulation types for effective use?

I've been attempting to learn C#.NET for the past month or so, and the array of ideas that seems to always trip me up is encapsulation. As this is one of the three pillars of OOP, I feel that I am ...
3
votes
5answers
730 views

Why is Encapsulation considered a primary principle in OOP?

I am currently trying to understand more deeply the 4 principles of OOP: Abstraction, Encapsulation, Inheritance, and Polymorphism. After studying the four principles, I don't fully understand why ...
3
votes
3answers
419 views

How does accumulating large amounts of business logic on the model objects make building strong service contracts harder?

I heard a couple of times that putting business logic in database models is bad down the road. I just read this in blog of a Rackspace employee: The Django ORM also tended to have us accumulate large ...
3
votes
4answers
622 views

Using lambdas to improve encapsulation

Just as many people believe tenaciously in small functions, some people believe lambdas should only contain small code fragments. An often overlooked advantage of lambdas however, is using them you ...
3
votes
1answer
770 views

What are the disadvantages of self-encapsulation?

Background Tony Hoare's billion dollar mistake was the invention of null. Subsequently, a lot of code has become riddled with null pointer exceptions (segfaults) when software developers try to use ...
3
votes
2answers
649 views

Encapsulation in Domain Driven Design models?

I am using EF Code First and I had a model like below. public class Account { [Required] public string AccountNo { get; set; } [Required] public decimal Balance { get; set; } } I ...
3
votes
1answer
174 views

Should I assert in packages? [duplicate]

I have read a few asserts vs exception questions already; I ask specifically about package visible classes though. When you write a package, the classes marked with "public" are exposed to the ...
3
votes
1answer
328 views

How to maintain encapsulation with composition in C++?

I am designing a class Master that is composed from multiple other classes, A, Base, C and D. These four classes have absolutely no use outside of Master and are meant to split up its functionality ...
3
votes
1answer
82 views

Should I write a wrapper within a manager object?

I have three classes that work together to do one function (from the perspective of the rest of my program). There is a little bit of set up between them, so, to make it easier for the rest of my ...
2
votes
6answers
692 views

Should I use automatic properties?

I'm new to C# coming from a Java background. I'm working on a take home assignment for a coding interview. I normally write my code as following(Java): public class Test { //fields private ...
2
votes
4answers
280 views

Function locals: variable used in just one function

In OOP, static scope means the scope is linked to the class, and instance scope is linked to a specific instance of the class. Some languages support static locals, which allow a value to be retained ...
2
votes
3answers
221 views

Abstraction concept in OOP

I hear that Abstraction is a technique that helps us identify which specific information should be visible, and which information should be hidden. Encapsulation is then the technique for packaging ...
2
votes
4answers
259 views

Why do some projects have getters and setters for public instance variables?

I was looking into an open-source game framework project written in Java. It has several classes that: Have public instance variables. Have getter/setters for such variables. Generally, I write ...
2
votes
3answers
174 views

Getters and Setters unclear example

I know autmatic getters and setters are considers bad as they tend to break object's encapsulation. They also move the work that should have been done within the object outside. Allen Holub is a big ...