Inheritance is a way to reuse code of existing objects, or to establish a subtype from an existing object, or both, depending upon programming language support.

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Confusion about inheritance

I know I might get downvoted for this, but I'm really curious. I was taught that inheritance is a very powerful polymorphism tool, but I can't seem to use it well in real cases. So far, I can only ...
2
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4answers
379 views

“Imprinting” as a language feature?

Idea I had this idea for a language feature that I think would be useful, does anyone know of a language that implements something like this? The idea is that besides inheritance a class can also ...
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7answers
1k views

OO Software Architecture - base class that everything inherits from. Bad/good idea?

I am reviewing a proposed OO software architecture that looks like this: Base Foo Something Bar SomethingElse Where Base is a static class. My immediate thought was that every object in any ...
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3answers
466 views

Inheritance: Is code from superclass virtually *copied* to subclass, or is it *referred-to by subclass*?

Class Sub is a subclass of class Sup. What does that mean practically? Or in other words, what is the practical meaning of "inheritance"? Option 1: The code from Sup is virtually copied to Sub. (as ...
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5answers
158 views

Should I use inheritance to differentiate objects even if they have the same fields?

Consider this simple class that models a real world mobile device: /// <summary> /// Model that represents a device. /// </summary> public class Device { public DateTime ...
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5answers
8k views

How to create a common interface for classes with different subsets of members

Don't know how to put it, But I'll try to be as clear as possible I have a project in which I am creating lots of classes and those classes have some common properties and methods but those methods ...
2
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3answers
309 views

Inheritance in imperative programming

My first introduction to programming was Java, which was horrible so I learnt Actionscript3 which was nice... "The point is" OOP was my introduction to programming where by I went on to gain a career ...
2
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5answers
457 views

Classic inheritance problem?

I keep seeing the following pattern when people learn about OOP: Problem: How do I put objects of different but related types into a container? Solution: Inherit from a common base class. New ...
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4answers
687 views

OOP concept: is it possible to update the class of an instantiated object?

I am trying to write a simple program that should allow a user to save and display sets of heterogeneous, but somehow related data. For clarity sake, I will use a representative example of vehicles. ...
2
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2answers
263 views

Is this the solution to static inheritance?

I've seen a lot of posts recently on why Singletons should be avoided. However, I can't see any of those problems with the following solution to a common problem: static inheritance. For example, I ...
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3answers
1k views

Why is inheritance only defined at compile-time?

I found this statement from the gang of four's "Design Patterns" particularly odd; for some context, the authors are comparing inheritance versus composition as reuse mechanisms [p. 19]: "...you ...
2
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4answers
5k views

Java class to enforce an implementation of super classes' public methods

I have the following : public Class A { public void methodA() { .... } public void methodB() { .... } } I don't have control over Class A. I would like to create ...
2
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1answer
64 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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2answers
654 views

One boilerplate class or many similar classes?

Lets say I'm trying to model a variety of objects that are virtually identical, the only difference being their class variables. Am I better off creating one boilerplate class and just calling the ...
2
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2answers
158 views

Wrapping constructor arguments

Given a base class with around 25 or so subclasses, I have found that adding an argument to the base constructor is painful. protected AbstractController(Service1 s1, Service2 s2, Service3 s3){ ... } ...
2
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1answer
489 views

The Better Parts and Delegation: Is Crockford Too Extreme?

Douglas Crockford has recently been giving a talk called The Better Parts. The gist of the talk is that JavaScript developers should actually avoid a superset of the The Bad Parts, which now includes ...
2
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2answers
65 views

How to ORM non-disjoint specializations

Consider this highly simplified sample of relational data (each table may be involved in one-to-many and many-to-many relationships not shown here): people +-------+------+--------+ | name | born | ...
2
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2answers
584 views

Having an inherited function return the derived type instead of the base type

I am writing two classes in C#: A Matrix class that represents a general Matrix with n-by-m dimensions A SquareMatrix class that inherits from Matrix and has the constraint of being n-by-n The ...
2
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2answers
84 views

subclass reference to another subclass

Imagine I have the following code: class A: pass class B(A): pass class C(A): def __init__(self): self.b = B() Is the above code correct in terms of correct inheritance? I ...
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5answers
2k views

What are the reasons to create UIView subclass?

I've noticed that there are a lot of UIView subclasses in my legacy project. Mostly the only reason of such a subclass is to split bigger view into custom subviews and provide layout for its subviews ...
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4answers
824 views

Explanation of the definition of interface inheritance as described in GoF book

I am reading the first chapter of the Gof book. Section 1.6 discusses about class vs interface inheritance: Class versus Interface Inheritance It's important to understand the difference between ...
2
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1answer
4k views

Adding base-class (inherited) functionality to classes that you don't control

I have a set of classes from a 3rd party library. These classes use an inheritance structure to share logic. I would like to add a layer of abstraction in the middle of their inheritance tree to add ...
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3answers
2k views

Are super methods in JavaScript limited to functional inheritance, as per Crockford's book?

In Douglas Crockford's "JavaScript: The Good Parts", he walks through three types of inheritance: classical, prototypal, and functional. In the part on functional inheritance he writes: "The ...
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1answer
475 views

Inheritance, Composition and Protocols

I'm reading a book on general object oriented concepts to try and gain a solid understanding of everything. One thing that is throwing me off is the difference between Inheritance and Composition. I ...
2
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1answer
100 views

Is this approach to CSS correct?

Reading SASS basic features on their website, I stumbled upon the @extend feature. The example they give is the following: .message { border: 1px solid #ccc; padding: 10px; color: #333; ...
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1answer
52 views

Keeping lists of Objects, some with, some without inheritance

Let's say I have two classes, Foo and ExtendedFoo where ExtendedFoo inherits from Foo. Foo has a method .getValue() which returns a number, ExtendedFoo also has .increaseValue() which adds to the ...
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4answers
233 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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2answers
215 views

Is doing Parent.call from the child object a right way to implement Inheritance in JavaScript?

I came across this piece of code it didnt look that right to me. Is it the right way to implement SUPER in javascript. if not what is the right way? function Person(name){ this.name = name; } ...
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4answers
254 views

Subclass only have methods without variables

Is it ok to have subclass which does not declare its own variables (instance variables) and inherits from super class or base class? It has methods and there are some common methods which it overides ...
2
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3answers
313 views

Is it appropriate to use inheritance to prevent code duplication of the logic for a user control?

Suppose I have two or more UserControl implementations with vastly different implementations but near identical code-behind. One strategy to avoid code duplication is as follows: Change each ...
2
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2answers
460 views

Testing abstract class' behavior

I'm currently refactoring an existing design, which was created without TDD. There is a class hierarchy with one abstract base class and two subclasses. In the original design, these classes were ...
2
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1answer
298 views

Class table inheritance… To 'type' or not to 'type'

I currently have a database that uses Class table inheritance model. Three different tables inherit from this table. The child tables have all a FK to the parent table and the fields are properly ...
2
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2answers
799 views

REST API wrapper - class design for 'lite' object responses

I am writing a class library to serve as a managed .NET wrapper over a REST API. I'm very new to OOP, and this task is an ideal opportunity for me to learn some OOP concepts in a real-life situation ...
2
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1answer
156 views

Should I use composition or inheritance for sharing configuration items?

I'm working on a fairly new project where I'd like to share some config items used by a JavaScript plugin. Specifically, the project is using jQuery dataTables and I want to find a good way of sharing ...
2
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1answer
164 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: ...
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0answers
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Can/should objects share methods in certain circumstances?

I am currently working on a web application that is supposed to resemble an operating system with GUI (it manages processes and windows). I have several constructors which deal with different aspects ...
2
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0answers
272 views

Reusable and customizable charting library on top of d3js

I have started building a charting library on top of d3js using javascript's inheritance. My goal is to develop reusable and fully customizable chart components. I read the article: Towards Reusable ...
2
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3answers
145 views

Refactor an old model of a LastUser Modification on every Object?

I have a software requirement, that needs to store the user that made the last modification to another object, for every object (assume that all objects are already mapped and into a BD). So we have ...
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3answers
714 views

Should utility base classes be avoided

Knowing that C# doesn't support multiple inheritance, is it considered bad form to write a utility base class? Some initial thoughts: I could create an interface and a concretion, but then the ...
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3answers
186 views

Does overriding a method affect a superclass's call?

I'm trying to understand some of the nuances of inheritance but I can't find an answer to this question. Consider the following: class SuperClass { method foo { print "in SuperClass.foo" ...
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3answers
277 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 ...
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2answers
149 views

Deriving from a class only to provide a special constructor

In our codebase, I encountered the following construct: There is a base class B, and then there is a class D which derives from B, but does not override or add any members. In fact, D is completely ...
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5answers
173 views

shall a vector2 extends a vector3 or is it the opposite?

Perhaps the question might be tied to a theoritical or mathematical forum, but since it is for programming purpose, i ask here first: In a computer vision context, i write a couple of interfaces ...
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1answer
123 views

Design Pattern - Adding features to a class

I'm finding myself unable to solve a design problem. For the sake of my simplicity, I'm going to use C# (Web API). Let's say I have an abstract class RestController: public abstract class ...
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1answer
244 views

Should I declare the most specific type as return type of method?

Sorry for my English In Android I can put only ArrayList of Parcelable objects in Intent: Intent putParcelableArrayListExtra(String name, ArrayList<? extends Parcelable> value); I can't put ...
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3answers
209 views

UML Class Diagram: How can I represent “orthogonal” generalizations (or multi-inheritence)?

I try to represent in a UML Class Diagram the following object and features: The Object: A System (e.g. an electronic device) that can be of Type A, B or C If the System is of type A, it has a ...
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2answers
153 views

Alternatives to inheritance on complex structures?

I'm working on an ASP.NET Webforms project, using the MVP Pattern (which the presenters as you may know use a Page Controller pattern). I'm given a rather complex inheritance chain for my controllers. ...
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5answers
246 views

Clarification about Polymorphism / Inheritance

I am trying to better my understanding of polymorphism. Say I have a base class called baseClass with one method called foo() and I have three derived classes called derived1 , derived2 and derived3 ...
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3answers
385 views

Does non-virtual-by-default lead us to composition-over-inheritance?

There are some design guidelines about testable code in “The Art of Unit Testing”. The first one is “Make methods virtual by default”. I’m curious to know your idea about non-virtual-by-default ...
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1answer
200 views

Inheritance or Composition?

Let's say I have a main class A and another class B. In the B class the user can change some settings and variables of the program that belongs to A, I want to be able to apply these changes to the A ...