The tag has no wiki summary.

learn more… | top users | synonyms

3
votes
2answers
73 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
votes
3answers
279 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 ...
0
votes
3answers
142 views

Why static members can't be abstract and don't implement polymorphism? [duplicate]

I'm a Java/C#/PHP developer, through my OOP programming experience I find myself asking the same question: Why static members can't be abstract and don't implement polymorphism especially in ...
0
votes
1answer
189 views

Is not being able to resolve a function call to its declaration a drawback of Polymorphism?

Consider a class that prints an "outline" table for a particular product line. Say you have several, A, B, C, D. The mechanism of the table generation is the same, but the data is different. I ...
2
votes
2answers
101 views

Is it possible to have Ad-Hoc polymorphism with runtime dispatch?

As I did understand, and as it's described here, ad-hoc polymorphism is limited to compile-time dispatch. That is, if we have a function that expects an argument that belongs to a typeclass, we must ...
2
votes
3answers
128 views

Why return back or assign to a supertype rather than the implementation type?

I have been doing a lot of reading about polymorphism, inheritance and typing (specifically how it applies to Java). I have seen some interesting examples, but not much explanation as to why. I.e.: ...
0
votes
1answer
182 views

Why overriding a static method does not result in polymorphism in java

Many say that we can not override a static methods. But we can override a static method. The question is, when we override a static method why it does not result in polymorphism ?
0
votes
1answer
95 views

Are there any programming languages that use strict evaluation that also have overloaded values?

Haskell supports overloaded values, where a single overloaded value can behave sort of like a superposition of values each with a different type. For example, here's a simple type class: class Truthy ...
2
votes
1answer
193 views

How do multiple levels of inheritance affect virtual function call overhead in C++?

I am considering using a class hierarchy with more than a single level of inheritance, where virtual member functions form a "chain", for example: struct Base { virtual void foo(); }; struct D1 : ...
1
vote
1answer
102 views

Ignoring the generic part of a type while an object is being passed

I have a message class that holds the name of a destination, and a generic variable acting as the message payload public class Message<T> { public string Destination public T Payload ...
1
vote
4answers
392 views

When to not use dynamic in C# [closed]

I'm making a class similar to the following: public class KeyValue { public readonly string key; public readonly object value; } Value could be of any object type as a result of this ...
2
votes
3answers
198 views

Is 'design with types first' ultimately the same as 'design with interfaces first'?

In Object Oriented Programming, we're taught to think in terms of Polymorphism (the idea that the implementation is decoupled from the interface - and that it makes sense to think of the interface ...
3
votes
1answer
187 views

Redundancy caused by polymorphism

I have two chat rooms, one has administration behaviour, and one doesn't. I have factored out all of the common code into a base chat room, but the AdministerChatroom behaviour I have pulled out into ...
17
votes
12answers
3k views

Is method overloading anything more than syntactic sugar? [closed]

Is method overloading a type of polymorphism? To me it seems like simply the differentiation of methods with the same name and different parameters. So stuff(Thing t) and stuff(Thing t, int n) are ...
3
votes
4answers
234 views

Is there a way to avoid type-checking in this scenario?

I have a class SuperClass with two subclasses SubClassA and SubClassB. I have a method in a different class which takes a SuperClass parameter. The method should do different things depending on the ...
1
vote
2answers
172 views

Is it an anti-pattern to use void* and enums to enable type-checking?

Say in a game engine, you have Objects that composited of different components. One of these is a RenderComponent which can be either a Mesh, a Sprite or a Light. Now, all these are vastly different ...
2
votes
2answers
256 views

Does it make sense to use interfaces if you don't have polymorphism?

Suppose I have distinct classes that have the same behavior, which can be represented like this: public interface Behavior { void operationA(); } public class ImplementerA implements Behavior { ...
0
votes
0answers
26 views

How to deal with multiple output modes of multiple types?

Note: The business domain being a bit complicated to explain, I replaced the names of actual classes by more illustrative examples. I'm writing an application in which the business layer returns a ...
2
votes
5answers
356 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 ...
1
vote
4answers
273 views

Combinatorial explosion of interfaces: How many is too many?

I'm a relative newcomer to OOP, and I'm having a bit of trouble creating good designs when it comes to interfaces. Consider a class A with N public methods. There are a number of other classes, B, C, ...
0
votes
1answer
124 views

Clean way to use mutable implementation of Immutable interfaces for encapsulation

My code is working on some compost relationship which creates a tree structure, class A has many children of type B, which has many children of type C etc. The lowest level class, call it bar, also ...
0
votes
1answer
149 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 ...
2
votes
1answer
127 views

What's the right OO way to create a counter/inventory class that works for both differentiated and undifferentiated countables?

You are writing a videogame about trading beans. Red beans, black beans, pinto beans, you name it. As everybody knows all beans are the same. You write the "Inventory" class for a trader in that ...
4
votes
4answers
4k views

What are the benefits of using Polymorphism 'in the real world' - as opposed to not using it? [duplicate]

I understand what Polymorphism is, but since I only ever programmed in Java and 'dived' pretty quickly into OOP, I'm having a hard time understanding exactly what it's benefits are (and I feel the ...
3
votes
1answer
139 views

Different scoring algorithms for different competition elements

I am creating a scoring system for a competition that is somewhat obscure, but it resembles the Olympics in terms of its high-level structure. Therefore, I will ask my question in terms of an ...
4
votes
2answers
801 views

What is the process of determining which method in a class hierarchy should execute known as?

I thought I understood inheritance and polymorphism, but I was given this question, and I can't, for the life of me, figure out what the proper answer is or what they're trying to get at: The ...
1
vote
2answers
153 views

Does subtype polymorphism distinguish between inheriting behavior, or inheriting an interface?

To provide some context, I've seen some comments lately that equate inheriting behavior from a supertype, with inheriting a pure interface with no behavior. But there are pretty significant, and ...
0
votes
0answers
94 views

Succinct Lazy Initialization Pattern

Background I often use the following lazy initialization pattern: public class Clazz { private Object object; private Object getObject() { Object object = this.object; if( object == ...
0
votes
0answers
41 views

How would I handle a set of differing event classes with differing handler interfaces in a single event processor?

I'm working on an event processor framework for a simple game I'm writing, in which multiple types of events are handled in a loop. Since these events carry distinct pieces of data (i.e. one carries a ...
1
vote
5answers
180 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 ...
4
votes
3answers
765 views

Java - Use polymorphism or bounded type parameters

Suppose I have this class hierarchy... public abstract class Animal { public abstract void eat(); public abstract void talk(); } class Dog extends Animal { @Override public void eat() ...
2
votes
1answer
117 views

Is it bad practice to encapsulate a single operation in a class? [duplicate]

I recently had a back and forth over at StackOverflow about my answer to this question. The question was simple. The author wanted to transform a number into an abbreviated version that appended a K, ...
1
vote
3answers
139 views

Refactoring - Utility classes behavior under a common interface

I was suggested to put my question here, so I'm doing so ;) I need a common interface which represents some specific behavior: public interface Contract(){ public void methodA(); public void ...
1
vote
1answer
378 views

Readability vs benefits of polymorphism

We are dealing with a lot of CRUD operations in our application. Each database table has one or more corresponding SQLContainer instances to perform various types of operations. All of these ...
2
votes
6answers
733 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 ...
0
votes
1answer
195 views

Does C++ support subtyping?

I know it might be a silly question to ask, but I didn't quite get an a absolute clear answer on this matter, so I thought I'd put it here. Does c++ support the subtyping in the sense that it ...
13
votes
4answers
691 views

Switch vs Polymorphism when dealing with model and view

I can't figure out a better solution to my problem. I have a view controller that presents a list of elements. Those elements are models that can be an instance of B, C, D, etc and inherit from A. So ...
1
vote
3answers
403 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
1k views

Interview question “What is virtual function”

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
486 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
148 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
171 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
119 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
471 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
853 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
470 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
562 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 ...
7
votes
4answers
741 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
5k 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 ...
7
votes
8answers
1k views

Introducing polymorphism to new programmers

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 ...