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

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130 views

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

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 ...
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1answer
81 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 ...
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0answers
39 views

Printing out 2d arrays which contain null values (java)? [closed]

I'm very new to Java and was wondering if there was a way to print out a 2d array which contains null values, but instead of writing null it just prints a space. My code so far is: for(int i=0; ...
5
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1answer
173 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 = ...
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5answers
3k 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 ...
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2answers
75 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 ...
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0answers
38 views

Searching for objects implementing a certain interface [closed]

I have an array of type Entity which contains objects that are subclasses of Entity. Some objects implement Clickable, and I'm trying to code a method that searches through the array and return ...
2
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1answer
71 views

Is Dependency Inversion a valid alternative to the pImpl idiom?

If I want to present to the user of my code an interface, that is unlikely to change, I can write only the public part of the classes in public headers and have a single private pointer to another ...
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2answers
101 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
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2answers
87 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 ...
8
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2answers
971 views

Is using interfaces for datatypes an anti-pattern?

Suppose I have a various entities in my model (using EF), say User, Product, Invoice and Order. I am writing a user control that can can print the summaries of entity objects in my application where ...
2
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5answers
169 views

Implement multiple separate interfaces or interface hierarchy

I've been refactoring one of my projects recently and ran into a decision I have to make. I have several interfaces: Entity: Something in the game world Actor: An Entity that can perform actions ...
2
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2answers
211 views

When to use a SortedMap interface?

The rule in programming is to use the most general interface possible. But the difference between Map and SortedMap is more subtle. They compile to the same bytecode [I think] No additional safety ...
2
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2answers
61 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
63 views

Interface design - Parameter choice

Situation: Is it better to have one or few parameters that supply more than enough information for the intended process or should you have more specific parameters that provide just enough ...
1
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0answers
23 views

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

I want my program to: 1) read some input lines from csv file 2) write the output lines to plain string file 3) read some input from the same file in (2) and compare it to some calculated data. I ...
1
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0answers
126 views

Java - Get Interface Generic Type

I'm trying to create an Interface with Generics which allows me to get the type of object in the generics but no matter what I try there's a syntax error. I've tried the following 3 methods. All of ...
0
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1answer
49 views

Implementing an interface already implemented by a parent class?

If a class extends a parent which defines an interface, should that class also explicitly implement the interface? As an example, is it better to include or remove the portion in square brackets ...
1
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1answer
53 views

Documentation of interfaces

I know how to document a function: /** * Prints a greet message to the web page */ function greet() { echo "Hi!"; } Or describe the usage of a variable: /** * @type string $name The user's ...
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4answers
224 views

How should nodes in a chain be connected?

Suppose you were building a system that receives data on one end and sends filtered data on the other end. The system is a chain of nodes, each receiving data from the node before and sending ...
0
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1answer
171 views

Interface or boolean?

I have a CustomObject class which has the abilities like being Clickable, KeyPressable and Movable. I created interfaces: IClickable, IKeyPressable and IMovable and make different CustomObject classes ...
5
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2answers
147 views

Is it good design to put abstract methods in an abstract class even though the methods are already defined in its interface?

Let's say we have an interface Foo with a method "public void someMethod()", and we have one or multiple abstract classes that "implement" Foo but don't necessarily themselves provide an ...
16
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4answers
2k views

Should a front-end developer ever specify JSON format for back-end developers?

I am taking the front-end role in a project. Should I be specifying for my back-end teammates the exact format of JSON that their PHP returns to my JavaScript? For example, should I be telling them ...
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0answers
73 views

How does one enforce the implementation of a static method? [duplicate]

Of course the answer to the question above is, "you can't". But I didn't have a better way of describing what I'm looking for. If I did, I wouldn't be asking this question. My problem stems from a C# ...
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0answers
36 views

Adding new Interface & Replacing Method with Interface Type

Let's say that I have 2 classes: Foo and Bar. `Foo` { List<Bar> bars String bippy() int boop() } `Bar` { int biz() String baz() } Observe that Foo's fields include a List<Bar>. ...
4
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3answers
273 views

Why use arg type `class Object` instead of `Comparable[]`?

In the code below, I believe it would look more appropriate to make the method argument be of type Comparable[] instead of Object[]. The first reason it would be more appropriate is that one can be ...
0
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2answers
172 views

Develop GUI and logic in a team the right way? [closed]

I am planning to start a small project with a friend. I will be developing the GUI using JavaFX in the MVC pattern and he will be responsible for the model/logic. My question is: how can we achieve a ...
0
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1answer
49 views

Interfaces between multiple projects

I'm slightly confused over the following: ProjectA -------- GetUsers (Implements IDBConnector) -------- IGetUsers -------- UserModel ProjectB -------- Main I have two projects one main project ...
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1answer
57 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 ...
0
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1answer
105 views

Async properties in interfaces to cater for the possibility of expensive first-time evaluation: Is this a good idea?

First of all, sorry if this post is too long. I'll start with the… Short version: Is it generally advisable or a good idea to design an interface property as asynchronous simply because we cannot be ...
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4answers
830 views

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

While defining the hierarchy, one can think to embed the abstract method(behaviour) in abstract class only because the derive concrete class posses that as core behaviour with it's specific ...
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2answers
337 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 ...
1
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2answers
152 views

Cleanest choice for symmetric operations

I have a need to do some processing from a format A to a format B and from B to A. The job in one direction is very similar to its counterpart. Both formats are represented with an interface Msg. In ...
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0answers
30 views

Restructuring similar interfaces to one unified design

In my project, I have several types of Web API controllers (and their corresponding services and repositories). When I started out, I made an interface of a generic type that would describe the basic ...
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4answers
2k views

Is it permissible to use explicit interface implementation to hide members in C#?

I understand how to work with interfaces and explicit interface implementation in C#, but I was wondering if it's considered bad form to hide away certain members that would not be used frequently. ...
2
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4answers
222 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 ...
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3answers
248 views

Implements > extends, but what about variables?

It's preferable to write programs that depend on interfaces rather than on superclasses, but what when you want a class to have certain variables? Sometimes you want a class to implement a certain ...
0
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1answer
91 views

when would you wrap a service object with an interface? [duplicate]

I'm new to UT and some of the best practices and anti-patterns when writing testable code, made me think. I used to wrap any service object with interface. but I see many mocking frameworks can ...
14
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2answers
2k views

Illegal in PHP: Is there an OOP design reason?

The below interface inheritance is illegal in PHP, but I think it would be fairly useful in real life. Is there an actual antipattern or documented problem with the below design, that PHP is ...
3
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1answer
169 views

Trying to get a better understanding of Interfaces

Im working on a small program and I thought i would use it as a chance to get a better understanding of things I haven't really used before, mainly Interfaces and Inheritance from base classes. ...
4
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1answer
124 views

Handling interface segregation in C++

I'm designing a "view" handling system for a game. The goal is to be able to have different "views" that can be shown in sequence or stacked on-top of each other. For example, the initial splash ...
3
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4answers
926 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: keep clients (using code) from being able to tell that a class is not a java interface. If ...
0
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1answer
146 views

Static methods vs Interface implementation

Here is my problem: I stared to create a e-commerce web sites info collector. So i created a parser for each site. The parser class is state less. got methods like: getItemPrice(WebElement page) ...
3
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3answers
210 views

Should I denote that a method satisfies an interface?

When writing a class which has ("satisfies") 1 or more interfaces, should I note somehow (e.g. in an XML comment, or with an attribute) that a particular method was added for one of the interfaces? ...
0
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1answer
196 views

Android, using a Fragment to hold/edit complex object, accesible from any Activity

I'll do my best to describe the problem, but I'm still very new to several concepts that I think this problem requires to be solved (namely interfaces and threads). I should preface this by saying ...
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2answers
139 views

How to organise and label methods, intended for debug?

I have a class System, which uses a bunch of other classes, to achieve a complex signal processing. In debugging System, one needs to observe the output signal for patterns. This is not achievable by ...
5
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3answers
237 views

Does it make sense to split up an existing multi-method interface into several single method interfaces just to take advantage of lambdas?

Say I have an existing callback interface that has multiple methods. To illustrate my point I use a callback the likes that you would see in code that performs some HTTP client operations: public ...
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0answers
165 views

How far to go when future proofing fluent-method-chained-DSL test code?

Is it worth implementing interfaces, or using the getThis() trick, or even static factory methods to future proof against the need to extend this DSL? The current design is a pair of thin ...
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2answers
90 views

Possible design patterns for base function with possible additions

I have various interfaces i have to implement. Let's assume ITypeA, ITypeB. They have following methods: ITypeA Connect Disconnect GetData SetData ClearData ITypeB Connect Disconnect ...
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2answers
197 views

Are there alternatives to using an optional type in a multithreaded environment?

I'm making an MPMC queue in C++, and I would like to find out what the best interface for a try_dequeue method would be (I'm not concerned about its implementation). I'd like to provide a method which ...