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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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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1answer
36 views

refactor by inheritance or composition for large class that depend on common state [duplicate]

I have a huge class (>1000 lines), in which all methods depend on a small set of attributes in that class. I can think of 2 quick ways of refactoring. I keep it as a huge object, but split related ...
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3answers
77 views

Heuristics on when should one subclass and when not [closed]

Are there any good tips, when one should subclass and when should not? It's clear that we should not subclass when we want to reuse a single method of some class we override all methods, changing ...
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2answers
477 views

Object inheritance and method parameters/return types - Please check my logic

I'm preparing for a test and doing practice questions, this one in particular I am unsure I did correctly: We are given a very simple UML diagram to demonstrate inheritance: I hope this is clear, it ...
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3answers
217 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 ...
0
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1answer
36 views

Class Table Inheritance: do child tables need a primary key?

I'm using the Class Table Inheritance architecture with my application and have read Fowler. When mapping my database tables to classes in code, I've realized I have no need for an "ID" property on ...
0
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2answers
222 views

block access to area/controller's methods but allow inherited controller to run methods, asp .net mvc5

I am trying to find out how to block a whole area/controller from being accessed by typing url website.com/area1/basecontroller/method1 (this area also contains the views that will be displayed) , ...
76
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9answers
6k views

Is there any “real” reason multiple inheritance is hated?

I've always liked the idea of having multiple inheritance supported in a language. Most often though it's intentionally forgone, and the supposed "replacement" is interfaces. Interfaces simply do ...
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3answers
142 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" ...
3
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1answer
149 views

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 ...
0
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2answers
129 views

Inheritance is a null property in the parent a bad practice?

I am not a very experienced programmer. So I ask. The field in question is the "Amount" field. I store an amount only in a couple levels of the derived class. The code is a slice of the POCO ...
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8answers
2k views

Is it good practice to inherit from generic types?

Is it better to use List<string> in type annotations or StringList where StringList class StringList : List<String> { /* no further code!*/ } I ran into several of these in Irony.
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4answers
725 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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1answer
148 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 ...
1
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1answer
26 views

Compose nested EventEmitters elegantly

I am developing a server-side JavaScript tool, and trying to do so in a modular way. I have a Parser class that is an EventEmitter - you call parse and it will eventually emit data and end events. It ...
1
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0answers
71 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# ...
2
votes
1answer
129 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 ...
3
votes
2answers
77 views

Database design for polymorphic data

I have an application that needs to log communications with users over several different mediums: Email, SMS, Voice, Website Announcements, etc.. in a traditional database. I have considered 3 ...
2
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6answers
739 views

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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2answers
141 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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6answers
18k views

Why are constructors not inherited?

I am confused as to what the problems could be if a constructor was inherited from a base class. Cpp Primer Plus says, Constructors are different from other class methods in that they create ...
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4answers
154 views

Is there an alternative to instanceof when filtering a Java stream by class?

I have an unexpected situation in a project in which all types extending one class are packed into a Java collection; but only a specific extension of that class contains an additional method. Let's ...
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2answers
72 views

what is the difference between inclusion and inheritance [duplicate]

the question is self explanatory, I just want to know when to use the inclusion and when to use inheritance, and which one serves for re-usability. in other words, which one meets the Object ...
2
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3answers
281 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 ...
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4answers
217 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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1answer
120 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 ...
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2answers
969 views

Code re-use in C++, via multiple inheritance or composition? Or…?

I originally asked this question on StackOverflow, but I was directed here, and I think my problem is perhaps as much conceptual as technical, so here goes. If you’re defining a hierarchy of abstract ...
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0answers
76 views

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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2answers
58 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 | ...
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1answer
66 views

Would this be considered a plugin or template type architecture?

I would like to build a system that basically offers the option to make various APIs interchangeable for usage to the end user. For example, the person using the software would have the option of ...
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3answers
234 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 ...
3
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2answers
100 views

Database Design for Inheritance

In my project I have an object Player (attr example: pl_id, pl_data1) that is one of these types: Its GoalKeeper (attr example: gk_data1) OR Defender (attr example: df_data1) OR Forward (attr ...
29
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9answers
4k views

Are abstract classes / methods obsolete?

I used to create a lot of abstract classes / methods. Then I started using interfaces. Now I am not sure if interfaces aren't making abstract classes obsolete. You need a fully abstract class? ...
46
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17answers
4k views

Is OO-programming really as important as hiring companies place it?

I am just finishing my masters degree (in computing) and applying for jobs. I've noticed many companies specifically ask for an understanding of object orientation. Popular interview questions are ...
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2answers
168 views

Why is inheritance generally viewed as a bad thing by OOP proponents [duplicate]

I keep hearing the phrase "Favour Composition over Inheritance" from GoF which is being annoyingly mentioned repeatedly by my friend who thinks it is a valid blanket statement but is it not more ...
2
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3answers
548 views

OOD: Java inheritance and access to child methods via casting

I have several classes Parent and Child1 ... Child9 implemented in Java. Parent is an abstract class, containing all the common variables of the child classes (a lot, which is the main reason why I ...
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1answer
167 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 ...
0
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1answer
159 views

overriding implemented base class methods

I read somewhere that the chain of inheritance breaks when you alter a behavior from derived class. What does "altering a behavior" mean here? Is overriding an already implemented method in base class ...
1
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2answers
140 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 ...
3
votes
2answers
425 views

Are there any OO languages without inheritance?

During a code review today, a colleague of mine said something interesting: prototype is only useful when you need inheritance - and when's inheritance ever a good idea? I thought about this and ...
36
votes
9answers
5k views

Is creating subclasses for specific instances a bad practice?

Consider the following design public class Person { public virtual string Name { get; } public Person (string name) { this.Name = name; } } public class Karl : Person { ...
2
votes
3answers
142 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 ...
44
votes
11answers
11k views

Why is it good to split a program into multiple classes? [closed]

I'm still a student in high school (entering 10th grade), and I have yet to take an actual computer course in school. Everything I've done so far is through books. Those books have taught me concepts ...
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vote
2answers
243 views

How to avoid redundant code in designing inheritance in C++

Say I have a Base class called Car and it has 3 derived classes say Ford, Honda and Audi. The issue is, all three derived classes have exactly same code but minor difference in calling member ...
2
votes
2answers
615 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 ...
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votes
1answer
122 views

Is this a good use of a base class? [closed]

I am developing some HW drivers, which access registers. I have a few classes, for example. ClassRegisterBlock1, ClassRegisterBlock2. In each of these classes, they define the bits to manipulate, ...
1
vote
2answers
282 views

Java: how can I make the return type, of an inherited method in a subclass, the same as the subclass?

I am rather inexperience in Java, and I'm having a problem in forming a subclass of a class I have created. The class I have made, called Vector2D, contains methods, such as add(Vector2D addend), that ...
2
votes
2answers
252 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 ...
3
votes
1answer
124 views

Augmenting functionality of subclasses without code duplication in C++

I have to add common functionality to some classes that share the same superclass, preferably without bloating the superclass. The simplified inheritance chain looks like this: Element -> ...
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1answer
232 views

Implementation of instance testing in Java, C++, C#

For curiosity purposes as well as understanding what they entail in a program, I'm curious as to how instance testing (instanceof/is/using dynamic_cast in c++) works. I've tried to google it ...