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

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5
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2answers
417 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 ...
15
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10answers
3k 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 ...
10
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7answers
3k 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 ...
9
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4answers
5k 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 { ...
39
votes
6answers
9k 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 ...
4
votes
3answers
144 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
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2answers
473 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 ...
13
votes
4answers
969 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
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3answers
556 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
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1answer
598 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
149 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 ...
9
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4answers
959 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
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4answers
3k 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
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7answers
1k 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
567 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 ...
8
votes
9answers
1k 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, ...
1
vote
1answer
198 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 ...
5
votes
4answers
382 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
282 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() { ...
3
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2answers
1k 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 ...
16
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10answers
14k 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
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4answers
2k 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?
6
votes
3answers
1k 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 ...
1
vote
6answers
433 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 ...
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vote
4answers
2k 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 ...
14
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5answers
2k 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 ...
0
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2answers
510 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 ...
9
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5answers
3k 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
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1answer
2k 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 ...
0
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5answers
2k 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 ...
13
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8answers
8k 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
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1answer
135 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
2k 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 ...
10
votes
3answers
769 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 ...
10
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5answers
1k 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 ...
3
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3answers
368 views

Naming conventions for the only envisioned implementation of an interface

If you decide "Program to An Interface" trumps YAGNI and decide to create a supertype where you don't envision anything other than one obvious implementation - is there a convention for naming the ...
5
votes
3answers
324 views

Should I provide synonyms in an API?

I'm designing a small library and there is a strong temptation to provide synonyms to some of the exported functions. var foldl = function(){ ... }; var reduce = foldl; //reduce is a synonym for ...
2
votes
5answers
638 views

Design Methodology for Developing Interoperable Systems?

A bit of background The company I work for has been creating database applications since around 1980 and, until relatively recently, most of these systems have been stand-alone "silo" systems. ...
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2answers
218 views

How is this “interface”-like structure/pattern called? [closed]

Let's assume we have an XmlDoc class that contains basic functionality for dealing with an XML data structure and saving/loading data to/from a file. Now we have several subclasses, A, B and C. They ...
9
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4answers
343 views

Are interfaces and method signatures copyright protected?

For example, is it copyright infringement if I write a class called Random with the exact same purpose and method signatures as Microsoft's .Net System.Random class? Does it make a difference what ...
1
vote
1answer
278 views

What's the best way to use a kinect with multiple software music synthesizers?

For the past few months I've been looking into developing a Kinect based multitouch interface for a variety of software music synthesizers. The overall strategy I've come up with is to create ...
5
votes
2answers
4k views

What is the proper way to implement the OnClickListener interface for many buttons

My Android Activity contains multiple buttons that all need an OnClickListener. I've seen lots of different ways of doing this such as:: Implementing the interface in activity class Creating a ...
2
votes
3answers
2k views

Why should I use interfaces if the implementation will mostly stay the same? [duplicate]

Possible Duplicate: Why are interfaces useful? In our company we have a service oriented architecture in our asp.net application. We use interfaces for every crap class. Its a huge ...
8
votes
11answers
762 views

Why do interfaces require methods over members?

...As this forces us to create getters and setters, which in practice are often totally extraneous? Is there any good language-design reason why interfaces in most (all?) languages do not allow member ...
4
votes
9answers
828 views

Does single inheritance limit what we can do with generalisation?

As a rule of thumb, generalisation is used only in specific circumstances. For example, when we can say that X is literally a subclass of Y. So, we can happily say that a Horse is a subclass of ...
38
votes
11answers
3k views

Is it bad habit not using interfaces? [closed]

I use interfaces rarely and find them common in others code. Also I create sub and super classes (while creating my own classes) rarely in my code. Is it a bad thing? Would you suggest changing ...
11
votes
6answers
1k views

How to implement only a part of an interface

When developing in OOP, sometimes an interface / contract is given by a library that you cannot alter. Let's call this interface J. Now you have an object of class A that consumes objects that ...
0
votes
1answer
648 views

Building a table (DataGridView) while keeping decoupled from Model

I'll try to keep this simple. Small C# app, dialog based, one has a DataGridView. I've got an UpdateTable function in the form that accepts a DataSet and passes it to the DataGridView.DataSource. ...
17
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4answers
12k views

Model-View-Presenter implementation thoughts

I'm trying to get a good grasp of how to implement good decoupling between a UI and the model, but I'm having trouble figuring out exactly where to divide the lines. I've been looking at ...
17
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3answers
1k views

Would adding award points or game features to workplace software be viewed poorly amongst the programming community?

So one of my responsibilities at work is to build an internal tool that helps the workers enter in all their information. It's an enterprise application that is similar to a Windows forms database ...