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

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270 views

Need some advice on CLI design, I need to provide simple but powerful command line options

I am writing a utility that runs on RHEL5 command line. I need my command line options to be simple but powerful. I looked at the various UNIX utilities to get an idea of how simple command line ...
2
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2answers
127 views

Java: Composition of classes implementing same interface

Let's consider an example wherein I have to model the following: Class to schedule exams for a Student, lets call it StudentExamScheduler Class to schedule exam for a Class. Let's call it ...
2
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2answers
77 views

Where to put configuration constants?

Considering a small embedded C project, how to decide if certain constants belong to a global configuration file the header of the "module == compilation unit" on top of the the actual C file or ...
2
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1answer
85 views

Reusing an interface or method chaining

I am learning about coding to an interface in OOP programming. I understand you should code to an interface so you can 'swap out' functionality. However, I have a situation where I feel I can reuse ...
2
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2answers
90 views

How do you maintain protocol of function return value in dynamic language?

In dynamic programming language like Python, Javascript, it's very easy to make a function return an object: def make_vector2(a, b): return {"x": a, "y": b} The 'signature' of the returned ...
2
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2answers
226 views

Are single method interface and function type definition the same?

In a language where it is possible to define interfaces and typedefs (using Dart here): abstract class Receiver { void receive(int quantity); } typedef void Receive(int quantity); abstract class ...
2
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2answers
305 views

Does it make sense to use interfaces if you don't have polymorphism?

Suppose I have distinct classes that have the same behavior, which can be represented like this: public interface Behavior { void operationA(); } public class ImplementerA implements Behavior { ...
2
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2answers
136 views

Why would an interface override methods of the interface(s) it extends in Java 7?

I was looking at Map and SortedMap documentation from Java 7 and I have realized that SortedMap, which extends Map overrides entrySet(), keySet() and values(). AFAIK, interfaces cannot implement a ...
2
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3answers
417 views

Manual Dependency Injection Examples Still Tightly Coupled

I've been using AutoFac for some time now to take care of the dependency injection we're using in a web project. All is well, but I now want to demonstrate DI outside of an AutoFac context for reasons ...
2
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1answer
144 views

Define an object with the interface as a type instead of class name [duplicate]

I try to practice with the design patterns and explore one of the possible implementations of the Observer Design Pattern in Java. I paid attention, that in this example the object is defined with the ...
2
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2answers
130 views

Do the implementations of the Node interface in Web API violate Liskov Substitution Principle?

MDN article on Node interface states that interfaces [that inherit from Node interface] may return null in particular cases where the methods and properties are not relevant. They may throw an ...
2
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2answers
116 views

How specific should be an interface about its implementation details?

Perhaps I should have picked a better title, but anyway... Basically what to do with two or more implementations that have the same public interface, but they are meant for slightly different ...
2
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2answers
147 views

Segregating interfaces/concerns to a tree

When working with a single object there are a number of ways to segregate interfaces to it. Breaking it into smaller components that can be treated independently. Breaking it into simpler interfaces....
2
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3answers
400 views

Why are inheritance and interfaces restricted to instance members?

Disclaimer: I think the rules are almost the same in most OO languages, but since I'm most familiar with C# I'll be relating to this specific language. I think that the use of attributes and ...
2
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2answers
1k views

Class design for calling “the same method” on different classes from one place

Let me introduce my situation: I have Java EE application and in one package, I want to have classes which will act primarily as cache for some data from database, for example: class that will hold ...
2
votes
4answers
357 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 ...
2
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3answers
3k 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 overhead. ...
2
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2answers
80 views

Revisiting Fowler's “Public versus Published Interfaces” article with regard to versioning and microservices

In this short article Public versus Published Interfaces from 2002, Martin Fowler distinguishes between easily changeable "public interfaces" and harder to change "published interfaces": The key ...
2
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1answer
125 views

Lower class count vs explicitness

To help with an application that manipulates and works from an XML structure to produce other information, I've created a class structure that closely follows the XML structure. So, the XML is: <...
2
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1answer
211 views

Application plugin system - interfaces - adding new features

Imagine I have an application, which have plugin system. public class MyPlugin : Plugin { public override ExecuteImpl (Context ctx) { // do something... } ...
2
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2answers
102 views

Delegating work and programming to component interfaces

I have a MessageHandler class which receives and validates messages before determining which components in the architecture they should be delegated to so they can be processed. This involves calling ...
2
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4answers
268 views

Determining a class structure

I'm currently in the early stages of designing an e-commerce application. I'm working out some designs for my classes which have so far been fairly straightforward, but I've run into something of a ...
2
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3answers
175 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 ...
2
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1answer
679 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 performer=(Performer)ctx....
2
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1answer
297 views

Structuring projects in a solution for interfaces

I had this idea that I would achieve some good automation and separation of concerns as follows: Define an interface, IDataProvider, in a class in a DataMuncher project that needs to both consume ...
2
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2answers
161 views

Correct approach for creating api contract

I am trying to design an API. For creating contracts below are the two approaches: Approach 1: public class MyController { public void MyAction1(Dictionary<string, dynamic> input) { //...
2
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2answers
282 views

Lesser of two evils regarding return types

I'm implementing a system in PHP where values are represented with objects that implement an Amount interface. I'm building two different implementations of this interface, one using a simple integer ...
2
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1answer
123 views

How modularized should my interfaces be?

I stumbled upon a specific instance where it seems that modularity and simplicity are at conflict with each other. Usually that's not the case, so I was really unsure how to resolve it. Suppose I ...
2
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1answer
169 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: ...
2
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0answers
104 views

What are the benefits of an input/output component design?

For the company I work at, all of our projects, including a new one started last year, are written in C89. We write for vxWorks (a real time embedded operation system). Our software runs multi-...
2
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1answer
160 views

Using own ArrayList in general purpose C libraries, but allowing a different implementation

I've written a couple of libraries since beginning to use C again last year. One thing that still needs addressing in both of these is the correct use of array-based lists - hereafter, ArrayLists. At ...
2
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0answers
217 views

The inheritance argument of zope.interface (providedby vs isinstance)

What limitations does inheritance of an interface through an abstract base class present that are addressed by zope.interface? In the following talk given in 2010 by Jeff Rush about interfaces, at 11:...
2
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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 ...
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11answers
262 views

Consistency of an object

I tend to keep my objects consistent during their lifetime. In some cases, setting up an object requires multiple calls to different routines. For example, a connection object may operate in this way: ...
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4answers
347 views

How can I avoid the use of strings?

I'm implementing a program where the user can 'create a musical scale' from a variety of notes (identified by their names), and the program will generate music from this scale. I want to implement a ...
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6answers
505 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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4answers
523 views

Implements > extends, but what about variables?

It's preferable to write programs that depend on interfaces rather than on superclasses, but what if you want a class to have certain variables? Sometimes you want a class to implement a certain ...
1
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4answers
507 views

Combinatorial explosion of interfaces: How many is too many?

I'm a relative newcomer to OOP, and I'm having a bit of trouble creating good designs when it comes to interfaces. Consider a class A with N public methods. There are a number of other classes, B, C, ...
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2answers
185 views

Could changing the return type from void to string introduce breaking changes?

This SDK have an interface like this: public interface Contract { void update(..); void action(..); void delete(..); } Now, we need to change it to something like this: public ...
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3answers
306 views

How can I sell DRY? [closed]

Where I work we have around 10 VS projects in a solution which are identical in functionality (with some different different rules in a few methods) and share many exact methods. They share the same ...
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2answers
479 views

Programming against interfaces in Java

Supposing I have an interface Foo and a given implementation FooImpl. public class FooImpl implements Foo If I want to define a new operation on this class that depends on the particular ...
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1answer
685 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 ...
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2answers
181 views

Should an abstract class always abstract its methods to an interface?

I had learned sometime ago that abstract classes should always abstract their functions to an interface. So instead of having something like this - abstract class a{ public int i; public int ...
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2answers
336 views

c# naming - What are common conventions for a suffix to distinguish between read-only and writable interfaces [closed]

Assume an interface that allows queries on a spatial tree public ISpatialTree { int FindChildIndex(Vector point); bool IsLeaf { get; } ICollection<ISpatialTree> Children { get; } } ...
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2answers
385 views

Violating the Interface Segregation Principle?

I currently have an interface named InternalEntityIdTransformer, which has a getInternalId method, that given an external id returns the corresponding internal one. Now I am working on functionality ...
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3answers
257 views

Should I use an interface when methods are only similar?

I was posed with the idea of creating an object that checks if a point will collide with a line: public class PointAndLineSegmentCollisionDetector { public void Collides(Point p, LineSegment s) { ...
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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 ...
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1answer
156 views

Should we “prefer composition over multiple interface”?

Should we avoid multiple interface if possible? Because I think at most cases a class with multiple interfaces can be replaced with another version with composition and single interface only e.g.: ...
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3answers
115 views

Same class and namespace name

I have a problem how to go about naming my namespaces and classes. I already figured they shouldn't both have the same name, as it causes all kinds of problems. Most notable problem for me is that I ...
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2answers
142 views

Should I be using IDisposable here, to properly manage memory?

Background I have an object that represents a test procedure that I need to run on a product. This object may be used multiple times during run-time, depending on how many times the user elects to ...