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

learn more… | top users | synonyms (1)

1
vote
4answers
346 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 ...
9
votes
5answers
430 views

Separate interface for mutation methods

I've been working on refactoring some code, and I think I may have taken the first step down the rabbit hole. I'm writing the example in Java, but I suppose it could be agnostic. I have an interface ...
2
votes
2answers
156 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) { ...
35
votes
4answers
29k views

Why were default and static methods added to interfaces in Java 8 when we already had abstract classes?

In Java 8, interfaces can contain implemented methods, static methods, and the so-called "default" methods (which the implementing classes do not need to override). In my (probably naive) view, there ...
3
votes
4answers
326 views

Design: Lisp (or other scripting language) as an interactive interface for C++?

I'm working on a medium size C++ project (will probably end up around 50k lines) and I have to provide an interactive terminal interface. The program produces scientific data as an output and the ...
1
vote
2answers
175 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 ...
3
votes
4answers
203 views

Design strategy for wrapping exceptions

I'm implementing a type of Repository for a framework/library that has (roughly) the following: public interface FooRepository { boolean contains(String id); Foo fetch(String id); void ...
1
vote
1answer
164 views

Inefficient use of interfaces in OOP (C#)

In my code, I've got two interfaces, let's say IOpenable and IExaminable. IOpenable allows the user to Open or Close the object, and IExaminable allows the user to Examine the object. Now, we have ...
2
votes
1answer
138 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 ...
11
votes
3answers
1k views

Is an interface considered 'empty' if it inherits from other interfaces?

Empty interfaces are generally consider bad practice, as far as I can tell - especially where things like attributes are supported by the language. However, is an interface considered 'empty' if it ...
1
vote
2answers
45 views

Declaring 'chained' interface inheritance

I assume this is largely language-agnostic, but I'm working in C# if it's not Let's say interface I3 inherits from I2, which in turn inherits from I1. I could write this: interface I1 { ... } ...
25
votes
4answers
18k 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 ...
0
votes
1answer
70 views

What should this interface contain?

I am creating a schema for Doctrine but first I'm creating interfaces, abstract classes (models) which will be extended by the entities. I have a PresentationInterface which contain getter and ...
3
votes
1answer
135 views

Interfaces, abstraction, coding to an interface

Original question here I am learning OOP and SOLID. I have a 'main' class that performs some actions after reading variables from a config file. This 'main' class is not the focus of this question ...
1
vote
2answers
236 views

Convert this abstract class to an interface

I have a security method I would like to be able to sprinkle into other classes throughout my program. It is currently an abstract class but I feel it would be more appropriate as an interface. Can ...
12
votes
2answers
532 views

UnsupportedOperationException in java collections framework interfaces

Looking through the Java Collections Framework, I've noticed quite a few of the interfaces have the comment (optional operation). These methods allow implementing classes to through an ...
0
votes
3answers
432 views

Why List<E> interface is additionally introduced in collection hierarchy? [duplicate]

Below is the diagram, where, if we just consider the implementations of List, AbstractList maintains the core behavior of list. To introduce the new implementation class MyList(say) one can ...
4
votes
1answer
17k 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
2answers
162 views

Advantages of these recommendations in ooprogramming using Java

Below are the recommendation from section 5.1 of this essay. While Java is not a pure object-oriented language, it is possible to program in a pure object-oriented style by obeying the following ...
3
votes
1answer
330 views

Creating an interface just to decouple from third party libraries

I'm currently developing the Authorization module on a framework of mine. I have the following class so far: public interface IAuthorizationManager<C> where C : ...
0
votes
1answer
80 views

What would this interface be called? [closed]

At work we have a java backend that talks to python on some mobile devices. The mobile devices have no GUI, it's just pure string manipulation. All contact is initiated by the python; the java is just ...
2
votes
1answer
89 views

How valuable is decoupling in proprietary software?

When developing with Symfony2 PHP framework I often see reccomendations to decouple code but most of the time that is accompanied by a 'if you want to release as a third party bundle'. Which begs the ...
1
vote
1answer
390 views

Static methods vs Interface implementation

Here is my problem: I stared to create an e-commerce web site info collector. So I created a parser for each site. The parser class is stateless. I have got methods like: getItemPrice(WebElement ...
1
vote
3answers
96 views

Programming to an Interface and Interface Segregation in the Context of a User Class [duplicate]

I try to program to an interface whenever possible, but its not clear to me how I could apply it to a model as broad as a user. Which can hold many disparate fields (name, age, phone number, ssn, ...
-2
votes
1answer
73 views

Programming to an Interface and Keep Testability in Unique Classes [duplicate]

I try to program to an interface whenever possible, but when I have a class that fulfills a very specific and unique purpose, one that can't be abstracted. Is it correct for me to say that I've ...
1
vote
1answer
49 views

Do my “dal” and “fileHandler” interfaces overlap?

I want my program to: read some input lines from CSV file write the output lines to plain string file read some input from the same file in (2) and compare it to some calculated data I want to ...
12
votes
1answer
758 views

Is it good practice to implement two Java 8 default methods in terms of each other?

I'm designing an interface with two related methods, similar to this: public interface ThingComputer { default Thing computeFirstThing() { return computeAllThings().get(0); } ...
2
votes
1answer
78 views

Repeating Interface inheritance declarations

Take the following example: public interface ISerialRVD { RouteValueDictionary ToRVD(); } public interface IViewModel : ISerialRVD // Here? { Int32 Page { get; set; } String Action { ...
7
votes
5answers
412 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 ...
1
vote
3answers
164 views

When is a event listener invoked during program execution?

I am using the Obervable-Observer Pattern. MyClass extends Observable{ invokeListeners(){ doSomething; setChanged(); notifyListeners();//This invokes onUpdate() in "implements ...
0
votes
1answer
91 views

Provide part of context to class using interface

Currently I have class Context which I inject in some places in my code, like: protected override object GenerateSomething (object input, Context ctx) Depending on Context, Generate method gives ...
2
votes
4answers
3k views

Why 'List<E>' is an 'interface' but not 'abstract class'?

Amidst defining the hierarchy, firstly, one can think to embed the abstract method(behavior) in abstract class only because the derive concrete class possess that behavior as core behavior with it's ...
3
votes
4answers
2k views

How to force “program to an interface” without using a java Interface in java 1.6

In java 1.8 they have wonderful new "default interface methods". In 1.6 how close can we come? The goal: use code to keep clients from being able to tell that a class is not a java interface. If we ...
9
votes
6answers
684 views

Does it always make sense to “program to an interface” in Java?

I've seen the discussion at this question regarding how a class that implements from an interface would be instantiated. In my case, I'm writing a very small program in Java that uses an instance of ...
2
votes
2answers
278 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 ...
21
votes
8answers
8k 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 ...
2
votes
1answer
200 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... } ...
28
votes
4answers
4k views

Why is .compareTo() in an interface while .equals() is in a class in Java?

I want to know why the .compareTo() is in the Comparable interface while a method like .equals is in the Object class. To me, it seems arbitrary why a method like .compareTo() is not in the Object ...
1
vote
0answers
241 views

Class Interfaces with Multiple Classes and Dependency Injection

NOTE ON QUESTION TITLE: I did not really even know how to phrase the title so if someone can edit and make it more articulate I would really appreciate it. QUESTION: Basically, what I'm trying to do ...
4
votes
2answers
170 views

Is it considered good practice to declare base interfaces without mutators, supplying mutatators in a sub-interface

I asked a question on StackOverflow on how to properly implement an ImmutableMap that abides by the SOLID principles. Due to Java's Map interface containing put and putAll, it violates the interface ...
3
votes
3answers
358 views

“One of some”-type

Say that you have some different classes that does not really have any functionality in common, but somewhere in your program, you need one of them (which one is not necessarily important) because ...
2
votes
3answers
193 views

Many different classes that need similar functionality. Best approach?

I have many (at the moment around 30) different message classes in an application I am creating. Each of these messages need to be serialized and deserialized. However, the process of serializing and ...
3
votes
0answers
95 views

License that encourages improvements to the original version rather than own forks? [closed]

I'm looking for a license that should encourage changes to my original open source rather than encouraging forks and uncontrolled random redistribution. This is because of the nature of the code; it's ...
1
vote
4answers
618 views

When to make a method part of an interface or a concrete implementation? [duplicate]

I create an interface for database access to a MySQL database. Currently, this is the only way to access day, but to make it easier to test and in the event that the data access might change, I used ...
0
votes
1answer
161 views

Can you refer to the callback function as an API?

A system design is decoupled into two layers say layer A and layer B. The interaction between layer A and layer B occurs through an interface that is exposed by layer B in form of an API. This ...
5
votes
1answer
220 views

Sometimes, “programming to interfaces” introduces possible (and avoidable) runtime exceptions?

Please consider the com.google.common.collect.ImmutableMap Programming to its interface, Map , creates a bug that could blow-up in the runtime as such: Map<String, Integer> myMap = ...
17
votes
5answers
4k views

Do enums create brittle interfaces?

Consider the example below. Any change to the ColorChoice enum affects all IWindowColor subclasses. Do enums tend to cause brittle interfaces? Is there something better than an enum to allow for ...
2
votes
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 ...
0
votes
2answers
163 views

Should I extend an interface or keep it independent?

I'm trying to decide whether to extend a base interface with additional methods or create several independent interfaces. I have a Task interface that looks like this interface Task { public ...
2
votes
2answers
101 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 ...