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1
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3answers
489 views

Is it bad practice to check object types with an identifying member variable?

Preamble: I am making a simple board game in C++, in which AI characters move around squares on the board. There are different types of squares, each inherited from an abstract class, each with ...
2
votes
2answers
2k views

Interview question “What is virtual function” [closed]

It was funny for me, and I'm interesting the reaction for this question of the community. It was interview for C++/Qt developer, and question was asked "What is virtual function". Not something like ...
8
votes
3answers
487 views

Two components offering the same functionality, required by different dependencies

I'm building an application in PHP, using Zend Framework 1 and Doctrine2 as the ORM layer. All is going well. Now, I happened to notice that both ZF1 and Doctrine2 come with, and rely on, their own ...
0
votes
1answer
165 views

Polymorphism versus authorization

I have something bother me in the understanding of polymorphism (vs role): Note: I am using rails (but it's a general question) I have 4 models: User Pro Customer Company There is a polymorphic ...
3
votes
2answers
194 views

how to follow python polymorphism standards with math functions

So I am reading up on python in Mark Lutz's wonderful LEARNING PYTHON book. Mark makes a big deal about how part of the python development philosophy is polymorphism and that functions and code should ...
0
votes
2answers
190 views

Making subclass more type-specific with accessors

I have a super class: TriggerManager with a subclass TimedTriggerManager. NOTE: I'm working in java TimedTriggerManager only deals with TimedTrigger s, a subclass of Trigger. TriggerManager ...
7
votes
4answers
511 views

Besides polymorphism, what's compelling about OOP? [duplicate]

When I first came to OOP (at first in Java, and then C++) after years of working in C and VB, it was amazing. The idea of extending existing behaviour and operating generically over things of related ...
5
votes
3answers
1k views

is down-casting always bad?

At my company, we have many different "services" that work in parallel and send messages to each other using a common messaging system. All message objects are derived from a common generic object we ...
3
votes
3answers
483 views

Novel polymorphism - any reasons for this code?

As part of my work on a legacy C# application I've come across a novel (to me) use of an interface & concrete implementations. I can't think of any reason why you'd do the following, but I'm ...
2
votes
2answers
652 views

Questions about Polymorphism

So I understand the importance of Polymorphism, including how vital it is. But something I don't quite understand is what about the Constructor and any inherited Class the initial Base Class may ...
8
votes
4answers
943 views

Design pattern for polymorphic behaviour while allowing library separation

Let's say I have a hierarchy of Item classes: Rectangle, Circle, Triangle. I want to be able to draw them, so my first possibility is add a virtual Draw() method to each: class Item { public: ...
6
votes
4answers
6k views

Replacement for instanceof Java?

So I'm fairly new to programming in the real world (outside of academic projects) and have come across lots of posts saying that using instanceof is a bad thing to use to determine what class a ...
8
votes
8answers
2k views

Introducing polymorphism to new programmers [closed]

I've been teaching Java to a group of four people for about four months now. Prior to this, they've all had very limited or no other experience programming. We've gotten through basic control ...
1
vote
2answers
122 views

Interface extension

Suppose that I have an input stream interface, which defines a method for reading data. I also have a seekable interface which defines a method for seeking. A natural way of defining a input file is ...
2
votes
1answer
455 views

What does “polyadic” mean in the context of functional programming and type systems?

And how does it (or does not) correspond to "polymorphic"? Occasionally I see this notion like in: Implement and represent polyadic operations. I checked Wiktionary but it only gives a general ...
12
votes
6answers
610 views

OO Design, how to model Tonal Harmony?

I have started to write a program in C++ 11 that would analyse chords, scales, and harmony. The biggest problem I am having in my design phase, is that the note 'C' is a note, a type of chord (Cmaj, ...
5
votes
1answer
568 views

Abstract Factory Method and Polymorphism

Being a PHP programmer for the last couple of years, I'm just starting to get into advanced programming styles and using polymorphic patterns. I was watching a video on polymorphism the other day, and ...
0
votes
1answer
531 views

Java Dynamic Binding

I am having trouble understanding the OOP Polymorphic principl of Dynamic Binding ( Late Binding ) in Java. I looked for question pertaining to java, and wasn't sure if a overall answer to how dynamic ...
4
votes
2answers
330 views

Alternatives to type casting in your domain

In my Domain I have an entity Activity which has a list of ITasks. Each implementation of this task has it's own properties beside the implementation of ITask itself. Now each operation of the ...
3
votes
3answers
2k views

How to setup the c++ rule of three in a virtual base class

I am trying to create a pure virtual base class (or simulated pure virtual) my goal: User can't create instances of BaseClass. Derived classes have to implement default constructor, copy ...
4
votes
2answers
475 views

Reasons behind polymorphism related behaviour in java

I read this code somewhere class Foo { public int a; public Foo() { a = 3; } public void addFive() { a += 5; } public int getA() { ...
5
votes
13answers
1k views

Limitations of Polymorphism in statically typed languages

I program mostly in statically typed languages, like C++ and Java. A common strategy employed in languages like these to handle dealing with collections of objects which are related, but which need ...
5
votes
2answers
2k views

Is dependency injection by hand a better alternative to composition and polymorphism?

First, I'm an entry level programmer; In fact, I'm finishing an A.S. degree with a final capstone project over the summer. In my new job, when there isn't some project for me to do (they're waiting ...
0
votes
4answers
661 views

Objective-C message passing related queries

I am learning objective-C after having good knowledge of C/C++. I have 2 questions: Are Obj-C message passing and C++ vtable, two different ways of implementing polymorphism or Are they two very ...
3
votes
3answers
10k views

What is upcasting/downcasting?

When learning about polymorphism you commonly see something like this class Base { int prv_member; virtual void fn(){} } class Derived : Base { int more_data; virtual void fn(){} } What is ...
4
votes
1answer
2k views

implicit vs explicit interfaces

I think I understand the actual limitations of compile-time polymorphism and run-time polymorphism. But what are the conceptual differences between explicit interfaces (run-time polymorphism. ie ...
9
votes
5answers
834 views

Writing Testable Code vs Avoiding Speculative Generality

I was reading some blog posts this morning, and stumbled across this one: If the only class that ever implements the Customer interface is CustomerImpl, you don't really have polymorphism and ...
-1
votes
4answers
253 views

Polymorphism confusion

I have read once in a book about exception where "an object of type Exception can be an instance of any subclassof Exception". I kinda get it, but there's still confusion can anyone clarify me the ...
1
vote
1answer
662 views

Can the Abstract Factory pattern be considered as a case of polymorphism?

I was looking for a pattern/solution that allows me call a method as a runtime exception in a group of different methods without using Reflection. I've recently become aware of the Abstract Factory ...
13
votes
5answers
2k views

Is duck typing a subset of polymorphism

From Polymorphism on WIkipedia In computer science, polymorphism is a programming language feature that allows values of different data types to be handled using a uniform interface. From duck ...
50
votes
17answers
5k views

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

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 ...