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

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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 ...
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2answers
228 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 ...
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2answers
501 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 ...
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3answers
409 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
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1answer
16k 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 ...
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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
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1answer
311 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
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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
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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 ...
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1answer
383 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 ...
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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, ...
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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 ...
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1answer
48 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
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1answer
736 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
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1answer
76 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 { ...
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5answers
410 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 ...
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3answers
159 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 ...
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1answer
85 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 ...
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0answers
104 views

Addicted to Interfaces - Good or bad? [duplicate]

After 2 years of programming, I usually found myself using the following design pattern: public interface ISomeInterface { void SomeMethod(); void OtherMethod(); } public abstract class ...
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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 ...
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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 ...
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6answers
665 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
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2answers
276 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 ...
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8answers
7k 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
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1answer
190 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... } ...
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0answers
72 views

Is using Interface implemented by single class a not recommended practice? [duplicate]

I have several classes in C#, not just POCO class but with methods and implementations. Each of those classes implement one Interface. e.g. IPerson implemented by Person class. Employee implements ...
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4answers
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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 ...
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0answers
231 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 ...
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2answers
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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 ...
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3answers
355 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
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3answers
189 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
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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 ...
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4answers
588 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
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1answer
159 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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1answer
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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
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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
88 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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2answers
161 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 ...
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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 ...
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2answers
340 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 ...
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5answers
3k 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 ...
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2answers
201 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 ...
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1answer
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Traits, Inheritance and Interfaces in Groovy, when to use them?

I'm learning groovy and I've just learned about the new feature added in 2.3, which is the addition of Traits. Now to me it seems like Traits allow you to do basically everything a super-class and an ...
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1answer
89 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 ...
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0answers
244 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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1answer
116 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
249 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
310 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 ...
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2answers
221 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 ...
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2answers
164 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 ...