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242
votes
17answers
18k views

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 being able ...
139
votes
13answers
91k 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 ...
87
votes
15answers
8k views

TDD Red-Green-Refactor and if/how to test methods that become private

as far as I understand it, most people seem to agree that private methods should not be tested directly, but rather through whatever public methods call them. I can see their point, but I have some ...
62
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 ...
47
votes
7answers
8k 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 ...
40
votes
8answers
10k 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 ...
30
votes
5answers
6k views

Why do we need enums in dynamically typed languages?

I was reading some code here and saw that an enum is used to store names of html tags. Why do we ever need to do this? What benefit do I get using this strategy? I know that how useful enums are in ...
24
votes
4answers
2k 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: ...
21
votes
6answers
2k 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 ...
19
votes
5answers
4k views

Is it okay for a class to use its own public method?

Background I currently have a situation where I have an object that is both transmitted and received by a device. This message has several constructs, as follows: public void ReverseData() public ...
18
votes
5answers
7k views

If a variable has getter and setter, should it be public?

If I have a class with a variable that is private and the class have getter and setter for that variable. Why don't make that variable public? The only case I think you have to use getters and ...
16
votes
9answers
1k views

Hiding away complexity with sub functions [duplicate]

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 ...
15
votes
6answers
7k 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 ...
15
votes
4answers
65k views

What is the use of Association, Aggregation and Composition?

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 ...
14
votes
6answers
2k 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 ...
14
votes
5answers
3k 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 ...
12
votes
4answers
1k 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 ...
11
votes
7answers
3k 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?
11
votes
4answers
1k 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 ...
10
votes
6answers
6k 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 to ...
9
votes
5answers
359 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
722 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
666 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
1k 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
5answers
414 views

Should private functions be held to the same standards as public functions?

If I'm building private utility functions, should they be held to the same rigorous standards in terms of handling invalid data as public functions? Example:If I'm writing code to calculate the ...
6
votes
6answers
2k views

What is the usefulness of private variables? [duplicate]

While I've never used a language that had built-in variable privacy, a book I'm reading by Douglas Crockford explains a way to create privacy in JavaScript, however it doesn't make sense to me so. The ...
6
votes
3answers
855 views

Can “higher order function” feature allow/maintain abstraction and encapsulation?

Below is the function repeat written using a functional paradigm, such that when called as repeat(square, 2)(5) it will apply the square function 2 times on the number 5, something like square(square(...
6
votes
4answers
822 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 ...
6
votes
2answers
909 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 (...
6
votes
4answers
3k 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
3answers
396 views

Best practices for using public, protected, private?

Is it fair to say that it is good practice to default everything to private up front when coding something? And then only upgrade it to protected if a subclass needs it, or public if another class ...
6
votes
6answers
2k 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 ...
6
votes
5answers
1k 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 ...
6
votes
4answers
340 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 ...
5
votes
1answer
417 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
4answers
402 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 ...
5
votes
3answers
2k 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
311 views

Do you generally send objects or their member variables into functions?

Which is generally accepted practice between these two cases: function insertIntoDatabase(Account account, Otherthing thing) { database.insertMethod(account.getId(), thing.getId(), thing....
5
votes
2answers
281 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
2k 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. Let'...
5
votes
2answers
622 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 ...
5
votes
1answer
495 views

How to store satellite data in C data structures

I've been reading through Introduction To Algorithms 3rd Ed, and I am having difficulty in implementing some practical situations. It's not the theory, or implementing the internals of the data ...
4
votes
4answers
903 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 ...
4
votes
3answers
1k 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
385 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
5answers
3k 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 ...
4
votes
2answers
278 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
4answers
187 views

Design question concerning proper and practical encapsulation

I have been working on refactoring old code and found a lot of instances of the following type of situation: There is a master object which we call "Application" and there is only one of these. The ...
4
votes
2answers
196 views

Does returning pointer to composed objects violate encapsulation

When I want to create an object which aggregates other objects, I find myself wanting to give access to the internal objects instead of revealing the interface to the internal objects with passthrough ...
4
votes
2answers
1k 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 ...