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.
3
votes
6answers
289 views
Can we say “If a parent class never appears in my codes except in its child class, it should be composition instead of inheritance”?
I read some posts about "composition over inheritance","where to use composition/inheritance" , "Is-a relationship..." or "Liskov substitution principle" for some time, but I am not sure if I get the ...
-2
votes
0answers
29 views
Simple inherit question? with javascript [migrated]
I am trying to figure out why object three won't access traits from object two when i use the document.write feature.
when I try to use this code on JS Bin "hello does not pop up on the screen like i ...
-2
votes
0answers
51 views
How to improve architecture [closed]
I've been presented with the following code and asked to improve the architecture. My thinking is going with interfaces and inheritance. Would you suggest using a design pattern? What would you ...
0
votes
2answers
123 views
Per my design requirements, does this design hierarchy seem reasonable?
Background
Construction
Note that I am using C# here, but it may not be necessary to provide input to my conceptual questions about design. Consider the following design methodology...
I work at a ...
9
votes
3answers
235 views
Are Python mixins an anti-pattern?
I'm fully aware that pylint and other static analysis tools are not all-knowing, and sometimes their advice must be disobeyed. (This applies for various classes of messages, not just conventions.)
...
0
votes
3answers
188 views
What to do if I need more than one base class in C#? [closed]
Let's say I have a grid with square fields. For the fields I have an abstract Field class. This class has several subclasses, for example EmptyField or RoadField. Some of these fields can be connected ...
8
votes
7answers
320 views
A property that can represent both a single date and a date range: How to properly model that?
I work in a system that can represent a "shipping estimate" in two ways:
A specific date: The item is guaranteed to ship at that date
A day interval: The item will be shipped "X to Y" days from ...
1
vote
1answer
100 views
Is this a misuse of “composition over inheritance”?
The general sentiment seems to be that composition is preferable, in most cases, over inheritance, as it leads to less coupling. But for a case like this,
module Publishable
def new?
...
2
votes
1answer
134 views
Creating multiple instances of an implementing class
I currently have an abstract class and multiple classes extending it. My problem is, that there has to be a way to create a variable number of instances of an extending class. The number of instances ...
2
votes
1answer
98 views
Child class accessing its parent's method from Ancestor method
I find myself right now banging my head with the following issue (in PHP):
I have an abstract base class, which has a non-abstract method, inherited and unchanged all over the inheritance chain ...
5
votes
1answer
86 views
How do I more effectively design this per its intended design while ensuring I'm meeting SOLID design principles?
I know what SRP is, but am questioning my current design of an object I call an entity. Below is a picture of the design I am referring to. If I shift the code from the GeometricInformation and ...
1
vote
1answer
104 views
How to avoid having nested generic in class
I'm working on a side project, and I turned on all rules for code analysis in Visual Studio, and I got the warning notice:
Warning CA1006 Consider a design where ...
3
votes
2answers
308 views
Cleanest way to expand a base class without explicitly mapping properties in C#
Lets assume I have following base class:
public class Base
{
public int Id {get; set;}
public string SomeText {get; set;}
public string SomeOtherText {get; set;}
public static Base ...
2
votes
2answers
200 views
Do common MVC frameworks violate the LSP and is there a MVC framework which does not?
You who have worked with a framework implementing the MVC architectural pattern most likely know how these frameworks are usually implemented.
They contain a base Controller class, which you extend, ...
2
votes
0answers
201 views
Is it a good practice to use virtual inheritance as default? [closed]
Why virtual inheritance is not used as default? Default as in by the programmer and not the language.
If not, why? What are the cases where it may fail? Is there some run time overhead? Is it ...
8
votes
4answers
397 views
Parallel hierarchies - partly same, partly different
There are quite a few similar questions out there 1, 2, 3, 4, but non seems exactly the case in this question, nor do the solutions seem optimal.
This is a general OOP question, assuming ...
4
votes
1answer
88 views
Is Python's inheritance an “is-a” style of inheritance or a compositional style?
Given that Python allows for multiple inheritance, what does idiomatic inheritance in Python look like?
In languages with single inheritance, like Java, inheritance would be used when you could say ...
2
votes
2answers
197 views
What is meant by reuse of inheritance?
A 2013 study of 93 open source Java programs (of varying size) found
that
While there is [no] huge opportunity to replace inheritance with composition (...), the opportunity is significant ...
2
votes
2answers
238 views
How much implementation should I provide in an abstract class? [closed]
I have an abstract class AbstractService and about 10 classes that extend from AbstractService. However, I'm not sure how many methods and what methods I should implement in the abstract class and how ...
-1
votes
1answer
117 views
Inheritance hierarchy design approach - Javascript [closed]
For the below code, that creates inheritance hierarchy,
function Animal(){
this.name = "Animal";
// toString is a function in the main Object that every
// object inherits from
...
-4
votes
1answer
74 views
What actually happens in inheritance (java)? [closed]
class A {
int a;
int b;
A(int i,int z) {
a = i;
}
void abc() {
System.out.println("a is " + a);
System.out.println("b is " + b);
}
}
class B ...
36
votes
5answers
2k views
How is defining that a method can be overridden a stronger commitment than defining that a method can be called?
From : http://www.artima.com/lejava/articles/designprinciples4.html
Erich Gamma: I still think it's true even after ten years. Inheritance is a cool way to change behavior. But we know that it's ...
0
votes
2answers
110 views
Best practice for encapsulating a parameter that requires multiple interfaces to be implemented
I encounter this issue multiple times, but I'm never sure how best to deal with it.
Basically, some methods I write require the implementing object to support multiple interfaces. The example I have ...
2
votes
3answers
89 views
Is there particular circumstance that throwing root superclass exceptions is a good practice?
I've been taught that exceptions should be have concise meanings and should contain a message that explains to the client what the exceptional situation is. I am wondering, since I found a piece of ...
0
votes
3answers
381 views
Using super keyword to access super class members
I have following questions about the super keyword in java:
I have a code below with classes:
A Extends no class contains integer variable i
B Extends class A contains integer variable i
C Extends ...
7
votes
5answers
454 views
Refactoring three very similar classes using inheritance?
I'm currently working on refactoring the code-base for one of our services. I'm been going through reviewing everything, and I feel it's a bit scattered, and could probably adhere to OOP principles ...
4
votes
3answers
315 views
Composition over inheritance but
I'm trying to teach myself software engineering and coming up against some conflicting information which is confusing me.
I've been learning OOP and what abstract classes / Interfaces are and how to ...
17
votes
1answer
2k views
Why not make a language with mixin-only inheritance? [duplicate]
It seems that in all class-based or prototypal OOP languages, mixins are either an afterthought or a secondary feature. However, to me it looks like traditional inheritance is just a specific case of ...
0
votes
2answers
338 views
Am I overusing Inheritance or this is exactly what it is here for?
I have a class called BagItem and another class called EquipmentItem both classes are exact the same in methods, etc, with the exception of 1 property.
BagItem have:
public InventoryBagType BagType ...
2
votes
4answers
166 views
Is it a good idea to make method behavior depend on the calling thread?
I want to subclass a 3rd party class, in order to make it thread-safe.
I have a good idea of how to implement this, but there is a problem: the superclass has a property, which affects the behaviour ...
1
vote
1answer
125 views
Is this the preferred way to do inheritance in JavaScript?
Hey there I'm not new to programming nor javascript but I'm new to the object oriented world of javascript as it differs from languages I know such as java, c# when it comes to object oriented ...
1
vote
2answers
205 views
To god (class) or not to god? [duplicate]
I'm working on a project that requires several different users in the system, all of which have overlapping responsibilities; we've isolated two possible ways of tackling this problem, but we're ...
0
votes
2answers
166 views
What is the pattern that uses multiple instances rather than multiple classes called? When would I use it?
Sometimes I find it useful to have a single class with multiple instances (configured differently via their properties), rather than multiple classes (inheritance).
??? Pattern
Single class (Fruit)
...
0
votes
1answer
72 views
Subclassing vs Using properties to discriminate types
Often when writing code I wonder what the best way is to discriminate between types (by which I don't necessarily mean types used in typesystems). That brings up 3 questions:
What is better?
When is ...
18
votes
1answer
497 views
Why does(/did) Bertrand Meyer think subclassing is the only way to extend a “closed” module?
In Meyer's Object-Oriented Software Construction (1988) he defines the open/closed principle as follows:
A module will be said to be open if it is still available for extension. For example, it ...
2
votes
2answers
311 views
Python OO problem
I started learning Python yesterday and I ran into a problem. I like to hear some thoughts on it.
As an exercise, I decided to build a chatserver. As part of the exercise, I wanted to write some ...
5
votes
8answers
304 views
Designing around shallow constness with inheritance
Background
I'm writing an image handling class. For this question two requirements of the class are of interest:
Must have "deep" const correctness.
Must allow sub-image aliases, a.k.a. sections or ...
1
vote
2answers
469 views
How to solve this inheritance problem
I have the following classes:
public abstract class StaticFileController<File, QueryData> : AsyncController
{
private string _resourceName;
public StaticFileController(string ...
-3
votes
1answer
63 views
How can we access non static protected method in main{as we cannot access protected members by creating objects} for java? [closed]
package foo;
public class scj{
protected void disp()
{
System.out.println("package");
}
}
*********************
import foo.scj;
public class aq extends scj{
public static void main(String ...
3
votes
5answers
309 views
Inheritance when following the Repository Pattern in PHP
I am trying to build a PHP application using the Repository Pattern but I'm not sure how I should implement the save method.
I have an abstract class called ItemRepository which have the following ...
3
votes
1answer
102 views
When are subclasses redundant?
I am working on a ML project that will involve malware and I want to represent the statistics files used for training the classifier via StatsFile objects. However, I am wondering whether I should use ...
0
votes
2answers
131 views
What exactly is interface compliance in C++?
I was reading this. It says that
Some people believe that the purpose of inheritance is code reuse. In
C++, this is wrong. Stated plainly, “inheritance is not for code
reuse.”
The purpose ...
1
vote
1answer
83 views
“Is a” relationship or, in other words Inheritance
Say I define an interface IAnimal which has a pure virtual (abstract) method called eat like this:
class IAnimal
{
virtual void eat(Food*) = 0;
};
In the future I inherit form IAnimal and create ...
1
vote
0answers
74 views
If the externally callable interface of a class is called its API, what is “what can be overridden” called?
It's about what the class gives access to through inheritance. It has a three letter abbreviation but not API. I've seen this before but can't remember at the moment.
The term is usually used in ...
1
vote
1answer
124 views
Accepted Patterns For Base Class with both Static And User-Defined Data Sources
I have a requirement to build a 'base' profile library (in C# - NET 4.5.2) for various different internal (technical) consumers. This profile consists of metadata fields that would be shared by a ...
4
votes
3answers
535 views
How can I add properties to subclasses and access them without casting from a superclass?
I'm trying to model a multi-dimensional point class in C#. I have about eight different types of points, and there may be more in the future. Right now, I have a superclass (PointBase) that holds all ...
3
votes
3answers
289 views
“Correct” way to use inheritance
Within a small project, a class Storage is meant to store any type of Item. Now, an Item has a String name, and an interaction. For example, a clock item might implement the interaction increment(int ...
4
votes
2answers
231 views
C++ design for encoder/decoder classes with different stored types
I need to handle different elements in a vector, each element owning a specific parameter (integer or string), so that I can easily handle encoding/decoding of a series of elements.
Encoding a list ...
11
votes
3answers
1k views
Is an interface considered 'empty' if it inherits from other interfaces?
Empty interfaces are generally consider bad practice, as far as I can tell - especially where things like attributes are supported by the language.
However, is an interface considered 'empty' if it ...
1
vote
2answers
43 views
Declaring 'chained' interface inheritance
I assume this is largely language-agnostic, but I'm working in C# if it's not
Let's say interface I3 inherits from I2, which in turn inherits from I1. I could write this:
interface I1 { ... }
...
