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.
4
votes
2answers
224 views
Why Java does not support private/protected inheritance like C++? [closed]
While inheriting a class in C++, user can specify the access specifier like,
class Base
{
public int mem1;
protected in mem2;
};
class Derived1 : **private** Base
{
// mem1 will be ...
4
votes
5answers
460 views
How often is Inheritance used?
I admit that I am a junior developer, and so far I've only built simple web applications in ASP.NET MVC. But I've never had to use the inheritance aspect of Object Oriented Programming in my own ...
19
votes
7answers
646 views
Should I test inherited methods?
Suppose I have a class Manager derived from a base class Employee, and that Employee has a method getEmail() that is inherited by Manager. Should I test that the behaviour of a manager's getEmail() ...
0
votes
1answer
103 views
Code reuse via inheritance [duplicate]
I have a set of classes that are all dealing with some related tasks. These tasks do have different inputs and outputs. This causes it to become impossible to have the tasks done via shared code ...
2
votes
2answers
77 views
Template method within one class without subclasses or inheritance
I have an algorithm with mostly invariant parts that needs to be reused within one class so as to stay DRY.
Code duplication with repeating method structure
public void save(String key, int value) ...
5
votes
2answers
161 views
How does strengthening of pre conditions and weakening of post conditions violate Liskov Substitution principle?
I read that Liskov substitution principle is violated if :
Pre conditions are strengthened .
Post conditions are eased out.
But I don't get fully yet how these two points would violate Liskov ...
25
votes
5answers
1k views
Many small classes vs. logical (but) intricate inheritance
I'm wondering what is better in terms of good OOP desing, clean code, flexibility and avoiding code smells in the future. Image situation, where you have a lot of very similar objects you need to ...
6
votes
1answer
225 views
Declaring functions as final… except when it is me who does the deriving
I have a class in which I want to disallow other programmers from overriding one of it's methods, since it requires special knowledge of the inner workings of the class. Since I personally know how ...
1
vote
1answer
127 views
How to share common methods if objects have different roles?
If 2 classes have the following in common:
part of how their state is represented (both have a linear container)
multiple identical methods (identical code, not just signature)
But are not ...
3
votes
5answers
651 views
Why does Java allow to implement different interfaces, each containing a method with the same signature?
I recently found out that I can have two interfaces, one containing a method with the same signature as a method in the other interface. And I can have an interface or class that implements both of ...
4
votes
3answers
377 views
Looking for a real-world example illustrating that composition can be superior to inheritance
I watched a bunch of lectures on Clojure and functional programming by Rich Hickey as well as some of the SICP lectures, and I am sold on many concepts of functional programming. I incorporated some ...
2
votes
2answers
300 views
Alternative to “inheritance versus composition?” [duplicate]
Possible Duplicate:
Where does this concept of “favor composition over inheritance” come from?
I have colleagues at work who claim that "Inheritance is an anti-pattern" and want to use ...
4
votes
2answers
277 views
Naming methods that do the same thing but return different types
Let's assume that I'm extending a graphical file chooser class (JFileChooser).
This class has methods which display the file chooser dialog and return a status signature in the form of an int: ...
1
vote
2answers
219 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 ...
0
votes
0answers
51 views
Class hierarchy problem in this social network model
I'm trying to design a class system for a social network data model - basically a link/object system. Now I have roughly the following structure (simplified and only relevant methods shown)
class ...
0
votes
2answers
81 views
How do you handle objects that need custom behavior, and need to exist as an entity in the database?
For a simple example, assume your application sends out notifications to users when various events happen. So in the database I might have the following tables:
TABLE Event
EventId ...
7
votes
1answer
303 views
JavaScript objects and Crockford's The Good Parts
I've been thinking quite a bit about how to do OOP in JS, especially when it comes to encapsulation and inheritance, recently.
According to Crockford, classical is harmful because of new(), and both ...
2
votes
7answers
574 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 ...
0
votes
5answers
564 views
Inheritance vs composition in this example
I'm wondering about the differences between inheritance and composition examined with concrete code relevant arguments.
In particular my example was
Inheritance:
class Do:
def do(self):
...
-3
votes
2answers
298 views
Why don't inherited methods use child properties? (PHP)
I'm trying to get the code below to work in child classes. But it keeps failing because it is checking the basicDbClass rather than the child class.
For those complaining and voting my question down ...
2
votes
5answers
1k 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 ...
3
votes
1answer
237 views
What is the best way to use inheritance with ORMs?
If I have a People table and those people can be at different addresses, and each address can have more than one person, thats a many-to-many relationship.
So, using ORMs like Entity Framework and ...
2
votes
7answers
533 views
Inheritance using non-abstract base class
This post is based on the question http://stackoverflow.com/questions/49002/prefer-composition-over-inheritance/11758048#comment15634305_11758048.
Some people said - check whether there is “is-a” ...
2
votes
1answer
288 views
Composition vs. Inheritance
Here's what is given:
public interface Request {}
// there are 20 subclasses of Request
public class CreateUserRequest implements Request {
@NotEmpty
public String userName;
}
// request ...
7
votes
9answers
904 views
What OO Design to use ( is there a Design Pattern )?
I have two objects that represent a 'Bar/Club' ( a place where you drink/socialise).
In one scenario I need the bar name, address, distance, slogon
In another scenario I need the bar name, address, ...
37
votes
11answers
3k views
Why is it good to split a program into multiple classes?
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 ...
2
votes
3answers
715 views
Can I use a child class variables in its parent class?
I am programming in Objective C, iOS. I create a Class A which is a parent class, and Class B inherits to Class A.
Now I have Class B variables which I also need to use in Class A. And also one ...
1
vote
2answers
452 views
Is it a good programming practice to have a class with several .h files?
I suppose the class have several different interfaces. Some it shows to some class, some it shows to other classes.
Are there any good reason for that?
One thing I can think of is with one .h per ...
3
votes
2answers
191 views
Does Parallel Inheritance Make for Good Code?
I'm writing a database interface in PHP and I have a base dbTables class, as well as a base dbTableFields class.
dbTables has a function, getFields(), that instantiates dbTableFields objects, each of ...
1
vote
2answers
111 views
Extend the API or use the same name as a class in the API?
I have been running into this problem more and more: I am not happy with the current API, and end up making my own class that does what I wish the API did; however, I don't extend the 'super class' as ...
4
votes
1answer
245 views
Any valid reason to Nest Master Pages in ASP.Net rather than Inherit?
Currently in a debate at work and I cannot fathom why someone would intentionally avoid Inheritance with Master Pages.
For reference here is the project setup:
BaseProject
...
3
votes
2answers
228 views
Derived Classes and namespaces
I am deriving a class, for use in my application, from a class provided by another group. Should the derived class be in the namespace for my application or the namespace of the parent class?
While ...
7
votes
6answers
844 views
Why is subclassing too much bad (and hence why should we use prototypes to do away with it)?
I was reading up on design patterns, and I read that the prototype design pattern does away with excessive subclassing.
Why is subclassing bad? What advantage would using a prototype bring about over ...
2
votes
1answer
838 views
Rails - to use STI or not…that is the question
Six months ago, I asked a question about modeling data for my app, and received some advice pointing me towards STI (see Rails data model - best practices question for the details).
I played around ...
7
votes
5answers
764 views
Interface and Inheritance: Best of both worlds?
I 'discovered' interfaces and I started to love them. The beauty of an interface is that it is a contract, and any object that fulfills that contract can be used wherever that interface is required.
...
20
votes
4answers
5k views
Why should I prefer composition over inheritance?
I always read that composition is to be preferred over inheritance. A blog post on unlike minds, for example, advocates using composition over inheritance, but I can't see how polymorphism is ...
5
votes
3answers
661 views
When calling a method should we use base.methodname and this.methodname?
In C#, with an inherited class set -- when calling a method should we use keywords 'base.methodname and this.methodname'... irrespective of whether it is a overridden method or not?
The code is ...
1
vote
2answers
976 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 ...
4
votes
2answers
273 views
Who decided on the terminology downcasting and upcasting?
As far as I know, the terminology comes from how the inheritance hierarchy is traditionally displayed, with the extending types at the bottom, and the parent types at the top.
This is a bit ...
14
votes
3answers
5k views
Best design for Windows forms that will share common functionality
In the past, I have use inheritance to allow extension of Windows forms in my application. If all of my forms would have common controls, artwork, and functionality, I would create a base form ...
9
votes
3answers
711 views
Inheritance vs mixins in dynamic languages?
When should you prefer inheritance patterns over mixins in dynamic languages?
By mixins, I mean actual proper mixing in, as in inserting functions and data members into an object in runtime.
When ...
0
votes
2answers
183 views
Inheritance versus Composition in a business application
I have a training management and tracking system, with a high level structure as follows:
We have a Role1, e.g. Manager, Shift-boss, miner, etc. and a Candidate, training for that Role. The role has ...
1
vote
2answers
123 views
Does hierarchial inheritance belong to the past? [closed]
Recently it came to my attention that hierarchical inheritance may be a relic of thinking of classes as "structs with functions" rather than a product contract-driven mentality.
Consider, as a simple ...
6
votes
5answers
345 views
Java without implementation inheritance
In a recent video on Java, Joshua Bloch states at 4 minutes 20 seconds into the video:
And then there's inheritance, and that was a marketing necessity. You know, we can argue whether you really ...
17
votes
4answers
3k views
How prototypal inheritance is practically different from classical inheritance?
Inheritance, Polymorphism, and Encapsulation are the three most distinct, important features of OOP, and from them, inheritance has a high usage statistics these days.
I'm learning JavaScript, and ...
22
votes
9answers
2k 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? ...
4
votes
6answers
220 views
Using all the parameters of a function
Code Complete (2nd ed.) says:
"If you pass a parameter to a routine, use it. If you aren't using it, remove the parameters from the routine interface."
However, in the past I sometime had to do ...
3
votes
1answer
230 views
Is it possible to refactor inheritance to composition when virtual methods are called inside the base class?
Let's say I have a class called Country and two subclasses called AI and Player. The Country class has a number of virtual methods to allow player-specific or AI-specific behavior.
I want to make it ...
6
votes
6answers
2k views
When you use inheritance to reuse code, do you find it too tricky that it swallows the benifits of reuse?
I've been coding for about 8 years, however I still find inheritance is too flexible and sometimes it makes you totally confused with the code you have written. One simplest example would be:
...
6
votes
1answer
186 views
“Super” vs “protected method” for running common code
In many langauges, super() lets you call the parent method which you have overridden. I've been using super in my Javascript (with fake object oriented implementation) to run common code for a long ...
