Questions about interface related design considerations, such as programming to the interface.

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3
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2answers
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Implementing the Interface Segregation Principle

Does this IConvertible interface satisfy the Interface Segregation Principle (ie. the "I" in SOLID)? Here is the definition: public interface IConvertible { TypeCode GetTypeCode(); bool ...
51
votes
10answers
14k views

Is better Show() + Hide() or SetVisible(bool visible)?

What is better and why? (From interface-design point of view) : a) To have two Show() and Hide() functions b) To have one SetVisible(bool visible) function EDIT: For example some object have ...
0
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1answer
98 views

Inverse of Extract Interface refactoring

I'm working with a Java project that has several interfaces, many of which have only one implementation. (See related question) For a given revision of the software, one could think this acceptable ...
0
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0answers
53 views

What should I do with too much interfaces needed for a dialog

Let me start by doing a small summary of the changes we did in our code in the last year. We have a software (VERY big) that is used to visualize multiples underground networks, enter data in the ...
2
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4answers
3k views

Understanding “programming to an interface”

I have come across the term "programming to an interface instead of an implementation" a lot, and I think I kind of understand what it means. But I want to make sure I understand it's benefits and ...
-1
votes
3answers
218 views

Regarding interfaces of classes in OOP

When one says "a class' interface": Does he/she refer to all of the get and set methods - or do they refer only to the methods' signatures and return types, without the inner implementation of these ...
24
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9answers
10k views

Default vs Impl when implementing interfaces in Java

After reading Should package names be singular or plural? it occurred to me that I've never seen a proper debate covering one of my pet peeves: naming implementations of interfaces. Let's assume ...
-1
votes
1answer
36 views

delivering ebook throught mobile app [closed]

I have designed the interface of a mag app which would deliver digitized magazine in the size of A3 paper to the mobile phone. My choice of fileformat is jpg of each of the pages, but is there any ...
0
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0answers
50 views

Use Objective-C protocols like Java interfaces [duplicate]

I'm a Java developer moving to Objective-C. So far in Objective-C I've seen protocols used extensively to implement the delegate pattern, but I haven't seen then to add a layer of abstraction in the ...
1
vote
2answers
953 views

Interface Segregation Principle - type hinting multiple interfaces

The question is about typehinting of the role interfaces. The code example has two DataMappers which typehint the interface they need in the constructor, FooDataMapper type hints the Preparable ...
1
vote
3answers
207 views

Refactoring - Utility classes behavior under a common interface

I was suggested to put my question here, so I'm doing so ;) I need a common interface which represents some specific behavior: public interface Contract(){ public void methodA(); public void ...
4
votes
4answers
10k views

Instantiating Interfaces in C#?

I am reading/learning about interfaces in C# at the moment, and thus far I managed to understand how it differs from an abstract class. In the book I am reading the author explains that interfaces are ...
1
vote
1answer
469 views

Interfaces, Adapters, exposing business objects via WCF design

I know there have been countless discussions about this but I think this question is slightly different and may perhaps prompt a heated discussion (lets keep it friendly). The scene: I am developing ...
0
votes
1answer
803 views

The real difference between web and native apps in mobile and smart devices [closed]

I still don't understand the difference between a native app and web or hybrid apps from the interface point of view. Now, apps such as Twitter, Facebook, etc. Are they native? or web? or hybrid apps? ...
2
votes
1answer
167 views

Using partially implemented interfaces

Consider the following hierarchy in C++ notation: class A { public: virtual void doStuff()=0; virtual void doOtherStuff()=0; }; class B:public A { public: ...
4
votes
5answers
628 views

Loose coupling and shuffling dependencies

I have a bunch of classes that look something like this: public class MyGame() { private Graphics graphics; private Player player; public MyGame() { graphics = new ...
5
votes
3answers
335 views

Interface at the class or function level?

I have been falling into a pattern lately where I have been defining routines that rely on an interface defined by a function that is specified as a parameter to the routine. (The language is C#, but ...
-1
votes
2answers
249 views

Programming beginner: Options for small program interfaces? [closed]

I have been a Rails developer for a year now, and I really want to start diving in to Ruby and pure programming without using a framework. However I am having trouble conceptualizing little programs I ...
3
votes
1answer
484 views

How does dependency inversion principle work in languages without interfaces?

In C#/Java, the dependency inversion principle is often demonstrated by high-level classes that depends on an interface/abstraction (that it owns). Low-level classes will implement the interface, thus ...
26
votes
2answers
2k views

What is the name of the following (anti) pattern? What are its advantages and disadvantages?

Over the last few months, I stumbled a few times over the following technique / pattern. However, I can't seem to find a specific name, nor am I a 100% sure about all its advantages and disadvantages. ...
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votes
12answers
2k views

Is “If a method is re-used without changes, put the method in a base class, else create an interface” a good rule-of-thumb?

A colleague of mine came up with a rule-of-thumb for choosing between creating a base class or an interface. He says: Imagine every new method that you are about to implement. For each of them, ...
11
votes
5answers
1k views

Should I write an interface API before an implementation?

I've been delving into more "organized" programming recently and I've been learning that I should be programming to an interface, not an implementation. With that in mind, would it be better to ...
1
vote
1answer
623 views

Interface Dependencies or Abstract Classes

I have a decision to make and I am wondering what would be the better solution. I am refactoring an older application and intend to really get into the nuts and bolts of it. There are 8 report types ...
2
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6answers
9k views

Design Patterns - Why the need for interfaces?

OK. I am learning design patterns. Every time I see someone code an example of a design pattern they use interfaces. Here is an example: ...
2
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4answers
872 views

Explanation of the definition of interface inheritance as described in GoF book

I am reading the first chapter of the Gof book. Section 1.6 discusses about class vs interface inheritance: Class versus Interface Inheritance It's important to understand the difference between ...
4
votes
1answer
146 views

C programming multiple storage backends

I am starting a side project in C which requires multiple storage backends to be driven by a particular piece of logic. These storage backends would each be linked with the decision of which one to ...
10
votes
4answers
10k views

The term “interface” in C++

Java makes a clear distinction between class and interface. (I believe C# does also, but I have no experience with it). When writing C++ however there is no language enforced distinction between class ...
4
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2answers
252 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 ...
0
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1answer
80 views

Inject specific classes or not

I have a TableSqlBuilder interface which has a method getCreateTableSql. This interface is used in some other class as follows: function createTable( $tableDefinition ) { $sql = ...
2
votes
3answers
172 views

Is it good practice to not filter values according to nullability?

Sometimes when I create an API that should enable getting a single value or all values I use the following pattern (passing NULL to the API, means get all rows): @Usernames - comma separeted list of ...
1
vote
3answers
255 views

How do I support interfaces for different devices in the same input scenario?

I asked this question on SO but someone pointed out that I would be better off here. He's most likely right. So here I go! So I just wanted an opinion. I have 2 different ways to approach the ...
1
vote
1answer
116 views

Generic service control interface

I need an interface to a back-end service, mostly for control commands (stop, status, cancel, reload config). The service might be in Python, Perl, Java, or whatever, and runs continuously. The ...
2
votes
1answer
181 views

Design of interface for finding one of something or a list

I am developing a telephony call model and thinking about how best to design the interface. One basic idea is that a call has a unique call identifier. I have a list of calls and finding a specific ...
5
votes
3answers
213 views

Where should I place my interface?

I have an interface to communicate with a DB (actually it is not a database, but this is to give a concrete example): interface DbInterface{ Result sendQuery(Query q); } And I am trying to ...
1
vote
0answers
176 views

Pattern or solution for using classes with different interface the same way

What I would like to achieve is to use classes (now two, later more) with different interface the same way, so I would like avoid using decisions based on the interface on upper levels for instance, I ...
2
votes
4answers
329 views

Why should IQueryProvider implementations throw NotSupportedExceptions?

Searching the web, we can find plentiful examples of various ORMs (nHibernate, EF, LinqToSql, etc.) that implement but don't actually support the full IQueryable<T> interface, throwing ...
4
votes
2answers
2k views

C++ class with only pure virtual functions: what's that called?

So i'm looking for some input/consensus on what terminology we should be using to describe something that looks like this: class Printable { public: virtual void printTo(Printer *) = 0; ...
1
vote
1answer
102 views

What to name a new interface that is replacing an existing one? [closed]

We're redesigning our application's plugin interface, so we're using the Adapter pattern with our proof-of-concept design to show that the new interface will function without committing to using it in ...
3
votes
2answers
1k views

Collection interfaces in C#, coming from Java

In Java, I'm used to declaring collections using the most-abstract interface possible and then constructing them using the concrete implementation that makes sense at the time. It usually looks ...
4
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4answers
11k views

Abstract class + Inheritance vs Interface

Hello fellow programmers, I am reading a book on C# and the author is comparing Abstract classes and Interfaces. He claims that if you have the following "abstract class:" abstract class ...
12
votes
5answers
3k views

What is the functional-programming alternative to an interface?

If I want to program in a "functional" style, with what would I replace an interface? interface IFace { string Name { get; set; } int Id { get; } } class Foo : IFace { ... } Maybe a ...
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votes
3answers
893 views

Programming to interface in Java [duplicate]

What is the real use of interfaces in Java? What is meant by programming to interfaces? I heard these things several times but I don't know what it is and why it is used.
2
votes
3answers
117 views

Can certain expectations of behavior be part of an interface's contract?

Given the following code: public interface IUserDataProvider { ICollection<SomeClass> getSomeClassRecordsForUser(int idUser); } Is it possible to define (via documentation) an ...
9
votes
3answers
10k views

Difference between various Collection Generic Interfaces in C#

I have been playing around with C# for Windows and ASP.net MVC development for some time now. But I am still unclear on a few areas. I am trying to understand the basic difference between and ...
7
votes
3answers
422 views

How do you find your way in deeply nested, interfacey code? [duplicate]

I know most people hate flat and long functions, and hate when code is not full of ISomethings. The problem is that I guess my mind works in different way, and I always have problems with that type ...
22
votes
9answers
3k views

Interface naming: prefix 'Can-' vs suffix '-Able'

It's common to use '-able' as a suffix for interfaces e.g. Serializable Printable Enumerable Drinkable Shootable Rotatable I was thinking that 'Can-' might better because it may be more descriptive. ...
12
votes
4answers
2k views

When to use interfaces (unit testing, IoC?)

I suspect I've made a schoolboy error here, and am looking for clarification. A lot of the classes in my solution (C#) - dare I say the majority - I've ended up writing a corresponding interface for. ...
10
votes
4answers
13k views

Who extends interfaces? And why?

AFAIK, my class extends parent classes and implements interfaces. But I run across a situation, where I can't use implements SomeInterface. It is the declaration of a generic types. For example: ...
34
votes
4answers
5k views

What did Rich Hickey mean when he said, “All that specificity [of interfaces/classes/types] kills your reuse!”

In Rich Hickey's thought-provoking goto conference keynote "The Value of Values" at 29 minutes he's talking about the overhead of a language like Java and makes a statement like, "All those interfaces ...
2
votes
2answers
2k views

Programming against a protocol in Objective-C

I stumbled accross the SOLID principles. There is one burning question. Should I always use protocols? I never saw someone using them in the way that a Java developer would use them. I tried it in a ...