Questions about interface related design considerations, such as programming to the interface.
4
votes
5answers
394 views
Should concrete classes avoid calling other concrete classes, except for data objects?
In Appendix A to The Art of Unit Testing, Roy Osherove, speaking about ways to write testable code from the start, says,
An abstract class shouldn't call concrete classes, and concerete classes ...
16
votes
5answers
1k views
Use of keyword “Using” in C# interface
When I'm using C# to write some code and I define an interface using Visual Studio 2010, it always includes a number of "using" statements (as shown in the example)
using System;
using ...
6
votes
5answers
288 views
Everything has an Interface [duplicate]
Possible Duplicate:
Do I need to use an interface when only one class will ever implement it?
I am taking over a project where every single real class is implementing an Interface. The ...
2
votes
4answers
993 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 ...
13
votes
4answers
401 views
Two interfaces with identical signatures
I am attempting to model a card game where cards have two important sets of features:
The first is an effect. These are the changes to the game state that happen when you play the card. The interface ...
0
votes
2answers
218 views
Why to say, my function is of IFly type rather than saying it's Airplane type
Say, I have two classes:
Airplane and Bird, both of them fly. Both implement the interface IFly. IFly declares a function StartFlying(). Thus both Airplane and Bird have to define the function, and ...
1
vote
3answers
2k 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 ...
0
votes
2answers
433 views
Java - What methods to put in an interface and what to keep out
I'm designing a file handler interface:
public interface FileHandler
{
public void openFileHandler(String fileName);
public void closeFileHandler();
public String readLine();
public ...
4
votes
2answers
367 views
Function that requires many parameters
I have a problem related to this:
Are there guidelines on how many parameters a function should accept?
In my case, I have a function that describes a rounded rectangle. The caller specifies
An ...
14
votes
10answers
1k views
Declaring interface in the same file as the base class, is it a good practice?
To be interchangable and testable, normally services with logic needs to have interface, e.g.
public class FooService: IFooService
{ ... }
Design-wise, I agree with this, but one of the things ...
9
votes
7answers
790 views
Interfaces on an abstract class
My coworker and I have different opinions on the relationship between base classes and interfaces. I'm of the belief that a class should not implement an interface unless that class can be used when ...
3
votes
4answers
672 views
Should interfaces extend (and in doing so inherit methods of) other interfaces
Although this is a general question it is also specific to a problem I am currently experiencing. I currently have an interface specified in my solution called
public interface IContextProvider
{
...
30
votes
6answers
4k views
What is the point of having every service class have an interface? [duplicate]
At the company I work at, every service class has a corresponding interface. Is this necessarily? Most of these interfaces are only used by a single class and we are not creating any sort of public ...
1
vote
0answers
105 views
Understanding interfaces [duplicate]
Possible Duplicate:
When to use abstract classes instead of interfaces and extension methods in C#?
Why are interfaces useful?
What is the point of an interface?
What other reasons are ...
0
votes
1answer
2k views
Difference between spring setter and interface injection?
I know how constructor and setter injection works in spring.
Normally I use interfaces instead of classes to inject beans using setter and I consider it as interface injection, but in case of ...
3
votes
3answers
128 views
What level of detail to use in an interface members descriptions?
I am extracting interfaces from some classes in .NET, and I am not completely sure about what level of detail of description to use for some of the interface members (properties, methods).
An ...
9
votes
2answers
375 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 ...
12
votes
4answers
567 views
Is there a different usage rationale for abstract classes/interfaces in C++ and Java
According to Herb Sutter one should prefer abstract interfaces (all pure virtual functions) to abstract classes in C++ to decouple the implementation as far as possible. While I personally find this ...
6
votes
3answers
296 views
Use cases for “private” interfaces?
I was wondering if there was a valid use case for being able to properly define the specific internal properties and functions of a class in a way similar to how an interface defines the public ...
5
votes
3answers
289 views
What do you call an interface with no defining methods used as property setters
In ASP.NET and C# I've ran across this before. Your class needs to implement interface ISomething in order for something in the super class to supply something to you.
I can't remember the details, ...
2
votes
1answer
300 views
Why this code create object as interface?
In am reading Spring in Action (3rd edition) and here a snippet from it:
ApplicationContext ctx=new ClassPathXmlApplicationContext("springidol.xml");
Performer ...
5
votes
2answers
128 views
Using a openid in a “closed system”
I would like to publish a website for certain family members only. Simply put, like a mishmash of family photos and videos. I want it to remain private, however.
I was considering using openid for ...
8
votes
4answers
446 views
Is it bad practice to use an interface for categorization only?
For example:
Say I have classes A, B, C. I have two interfaces, lets call them IAnimal and IDog. IDog inherits from IAnimal. A and B are IDogs, while C is not, but it is an IAnimal.
The important ...
8
votes
4answers
883 views
Return interface or class
Suppose I have a method
public List<User> GetBatchOfUsers(IEnumerable<int> userIDs)
{
List<User> users = new List<User>();
// some database stuff
return users;
}
...
2
votes
7answers
974 views
Architectural patterns for interaction beyond MVC? [closed]
We all know the venerable Model-View-Controller pattern used to design interaction [mostly] with human users. It is the de-facto standard in OOP environment.
What are some other architectural ...
4
votes
2answers
307 views
Storing IEnumerable as instance variable - is it a code smell to expect it to change?
I have something that works like a fixed size list - it's actually called FixedSizeStack<T> in my program. I will use it to represent the X last occured events. This event list will then be ...
7
votes
9answers
943 views
What OO Design to use ( is there a Design Pattern )?
I have two objects that represent a 'Bar/Club' ( a place where you drink/socialise).
In one scenario I need the bar name, address, distance, slogon
In another scenario I need the bar name, address, ...
0
votes
1answer
100 views
The design of a generic data synchronizer, or, an [object] that does [actions] with the aid of [helpers]
I'd like to create a generic data-source "synchronizer," where data-source "types" may include MySQL databases, Google Spreadsheets documents, CSV files, among others. I've been trying to figure out ...
3
votes
4answers
217 views
Passing compound object for parameters
I have different data modules, which take a couple of parameters from a configuration list. Do you think it's ok to pass a configuration object as a whole module1(config) and let the module pick what ...
3
votes
2answers
180 views
Is this a pattern? Proxy/delegation of interface to existing concrete implementation
I occasionally write code like this when I want to replace small parts of an existing implementation:
public interface IFoo
{
void Bar();
}
public class Foo : IFoo
{
public void Bar()
{
...
1
vote
2answers
523 views
Is it a good programming practice to have a class with several .h files?
I suppose the class have several different interfaces. Some it shows to some class, some it shows to other classes.
Are there any good reason for that?
One thing I can think of is with one .h per ...
12
votes
10answers
3k views
Why use an interface when the class can directly implement the functions? [duplicate]
Possible Duplicate:
Why are interfaces useful?
Like most faculty, my java faculty introduced interface without explaining or even mentioning its practical use. Now I imagine interfaces have ...
3
votes
4answers
938 views
How can I explain C# interfaces, and constructors to a 8 years old kid?
How can I explain C# interfaces and constructors to a 8 years old genius kid?
5
votes
3answers
482 views
Checking preconditions or not
I've been wanting to find a solid answer to the question of whether or not to have runtime checks to validate input for the purposes of ensuring a client has stuck to their end of the agreement in ...
0
votes
6answers
316 views
Interfaces: profit of using
First of all, my ubiquitous language is PHP, and I'm thinking about learning Java.
So let me split my question on two closely related parts.
Here goes the first part.
Say I have a domain-model ...
1
vote
4answers
956 views
Teaching java interfaces to absolute beginners: What is a good example? [duplicate]
Possible Duplicate:
Explaining interfaces to beginning programmers?
I searched on stackoverflow and here for a good example to
teach java interfaces in a beginners class.
I found the ...
12
votes
5answers
610 views
How do you evolve & version an interface?
Say you have an interface IFoo:
public interface IFoo {
void Bar(string s);
int Quux(object o);
}
In version 2 of your API, you need to add a method Glarg to this interface. How do you do ...
7
votes
3answers
2k 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:
...
0
votes
2answers
313 views
Is this bad design for a Shape interface?
I'm creating a vector editing program in C++, and I need a Shape interface which other concrete classes will implement. There is a requirement that no implementation inheritance is allowed. The design ...
2
votes
4answers
1k views
What are good reasons to use explicit interface implementation for the sole purpose of hiding members?
During one of my studies into the intricacies of C#, I came across an interesting passage concerning explicit interface implementation.
While this syntax is quite helpful when you need to resolve ...
7
votes
5answers
914 views
Interface and Inheritance: Best of both worlds?
I 'discovered' interfaces and I started to love them. The beauty of an interface is that it is a contract, and any object that fulfills that contract can be used wherever that interface is required.
...
4
votes
1answer
616 views
implicit vs explicit interfaces
I think I understand the actual limitations of compile-time polymorphism and run-time polymorphism. But what are the conceptual differences between explicit interfaces (run-time polymorphism. ie ...
20
votes
4answers
6k views
Why should I prefer composition over inheritance?
I always read that composition is to be preferred over inheritance. A blog post on unlike minds, for example, advocates using composition over inheritance, but I can't see how polymorphism is ...
0
votes
5answers
1k views
Why does the use of interface-based programming appear to be limited to behaviour?
I have been doing a little thinking about inheritance vs. realization vs. composition. I am not about to post the whole detail here. So I was wondering, when we are not talking about creating ...
21
votes
9answers
1k 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. ...
10
votes
8answers
2k views
What is the point of an interface? [duplicate]
Possible Duplicate:
When to use abstract classes instead of interfaces and extension methods in C#?
What other reasons are there to write interfaces rather than abstract classes?
This ...
6
votes
1answer
124 views
Private interfaces within a package
This is basically the same as Coding to interfaces, but played out in the real world of com when there are various engineering complexities such as immutability of published interfaces and ...
1
vote
2answers
824 views
What other reasons are there to write interfaces rather than abstract classes? [duplicate]
Possible Duplicate:
When to use abstract classes instead of interfaces and extension methods in C#?
When I read and looked at codes using Abstract classes, I was able to justify it because ...
8
votes
3answers
542 views
How do existential types differ from interfaces?
Given the existential type
T = ∃X.{op₁:X, op₂:X→boolean}
and this generic Java interface:
interface T<X> {
X op₁();
boolean op₂(X something);
}
What are the fundamental differences ...
9
votes
5answers
721 views
Modified Strategy Design Pattern
I've started looking into Design Patterns recently, and one thing I'm coding would suit the Strategy pattern perfectly, except for one small difference.
Essentially, some (but not all) of my ...
