A methodology that enables a system to be modeled as a set of objects that can be controlled and manipulated in a modular manner
-1
votes
0answers
67 views
Necessary thing for keyword “new” in c++ (oop) [on hold]
I am looking for the answer to a question which is as follows:
What is the necessary thing for the keyword "new" in c++ or oop c++?,and is there any difference between "new operator" and "new ...
-4
votes
2answers
42 views
Cache repository violating the SRP
interface IRepository {
Data getData();
}
class BaseRepository implements IRepository {
public Data getData() {
...
}
}
class CacheRepository implements IRepository {
private final ...
31
votes
5answers
3k views
When should I extend a Java Swing class?
My current understanding of Inheritance implementation is that one should only extend a class if an IS-A relation is present. If the parent class can further have more specific child types with ...
-6
votes
0answers
61 views
Help me in this java programs [on hold]
Write a program:
Must start if user says hello
Has to repeat until the user says bye
Ask user to enter his or her name, let him or her know if the entered name contains space or dot.
Each time print ...
-3
votes
0answers
47 views
Type safe substituion for parameter passing [on hold]
What are some examples of type safe substitution for parameter passing as well as for return types in subtyping introduced through subclassing. Does the Liksov Substitution Principle apply to them?
1
vote
1answer
39 views
How to use fields from an object after an exception is thrown and the object can't be fully created
The issue that I have is that I need information from an object that a method returns when it throws an exception. It is a little hard to describe so I have this java pseudo code example. I have a ...
0
votes
0answers
43 views
Good examples for use of design patterns in Unity [closed]
My students have learned OOP as well as the strategy design pattern during the first semester (Processing/Java), which lead to understanding Unity's component based architecture (similarity of ...
1
vote
0answers
15 views
How to Make Reusable Classes/Package in Laravel for Billing which uses PaymentExpress?
I am working on a Laravel Project where we are Payment Express. What currently we are doing is that we have Payment Express Class with static function (Not a single property) like given below:
Class ...
6
votes
1answer
430 views
How to make clear that a method can be overridden?
I have a library that I use in several applications. It has a method that returns a URL:
class UrlBuilder {
public function url($config) {
$config = do_some_checks($config);
return ...
5
votes
3answers
213 views
Is it ever appropriate to use subtyping for a has-a relationship?
One of the basic precepts of object oriented programming is that subtyping represents the "is-a" relationship. That is, the child is always a specific form of the parent. A common example is that a ...
1
vote
1answer
37 views
In a .NET Windows Forms app with a custom MVC, should a custom UserControl (view) implement any non-animating logic on its own?
This is strongly linked to these two questions:
http://stackoverflow.com/q/15800945/279112
Should Controller know about View & Model? or vice versa?
as well as this one:
...
2
votes
1answer
141 views
Checking preconditions the proper way
I have a class with around 1300 lines and it has many CRUD-like methods that need parameters to be checked, for some of them it's more than just a few rules.
For clarity purposes, I am going to use ...
4
votes
3answers
139 views
Who is responsible for checking object properties such as Visible/Enabled?
Say we have a user interface with Forms, Buttons and such. Each item has some properties (such as Visible, Enabled, etc.). Who should check on these properties and decide whenever to render the item ...
3
votes
1answer
207 views
How to pass data to OOP objects?
I'm new to this whole thing, so please tell me if I'm doing this wrong of if there's a better spot for my question.
I'm making a game with basic systems for projectiles, npcs and items. This game ...
1
vote
0answers
31 views
Why Does JavaFX's GridPane Attach Properties of the Layout to the Components?
I am currently learning JavaFX and I came across a very strange API for laying out GUI components. It is perhaps best explained by it's javadoc:
To use the GridPane, an application needs to set ...
9
votes
3answers
253 views
OOP design problem. Two kinds of empty Optional
I'm writing a quite simple application that deals with hotel rooms reservation. I've got a problem at one stage.
I'm processing a queue of orders. For every order one of the receptionists should ...
3
votes
5answers
187 views
What is the correct OOP relation between complex and real numbers?
On one hand
class complex {
double real;
double imaginary;
}
it is composition
on the other hand
class complex : double {
double imaginary;
}
it is inheritance
Which one is ...
-1
votes
1answer
38 views
algorithm to convert technical specification into object model [closed]
I have detailed specification of what should my program take as input, and give as output.
How to convert this specification into classes/methods/properties?
I used such algorithm:
Take ...
1
vote
1answer
46 views
Redesigning a builder to make it reusable
Let's say I have a builder class (which by the way is not techinically a builder, but it's not a factory either) to generate different rules for a game:
public class RuleBuilder {
private Game ...
-1
votes
2answers
97 views
Do you say “this” on protected members? [closed]
Background
I have never had a formal class in OOP/OOD although I understand how the protected members work. Being accessible by any instance/derived class, they are thereby less private (more ...
13
votes
4answers
1k views
How specific should the Single Responsibility pattern be for classes?
For example, suppose you have a console game program, which has all kinds of input/output methods to and from the console. Would it be smart to keep them all in a single inputOutput class or break ...
2
votes
2answers
84 views
How to handle when only certain derived classes need to be disposed?
I am trying to build a framework of objects where the main actors can be interchanged freely. At the moment I've done this by creating an abstract base class that all of my actors can be derived from. ...
1
vote
1answer
179 views
OOP: how to keep some state for a brief moment?
My job and my personal interests often have me writing parsing code, that is, code that converts from an input string written in a given formal language to a tree of model objects.
I come from a C ...
1
vote
2answers
64 views
Implementing an event scheduler for animations
The basic idea is to have some animated widgets that sit in a container, quite similar to Qt (the only actual difference is that my widgets are animated).
The animation is in some cases dependent on ...
0
votes
1answer
138 views
What would be the merits/disadvantages of an OOP language that forced the generator pattern?
In OOP languages, programs can define static methods that can generate objects with different parameters (including subclassed or pre-generated objects), but they are not as commonly used because we ...
0
votes
1answer
71 views
Passing a Serial Port Instance
Background
I am thinking about designing a (GoF/behavioral) command-pattern interface. I may decide to call this thing ICommand. I am thinking that I would have some sort of a queue containing a ...
5
votes
3answers
106 views
Understanding Multiple Dispatch
I've been reading around trying to understand multiple dispatching, and why it's so special.
On Wikipedia I came across this simple example:
(defmethod collide-with ((x asteroid) (y asteroid))
...
1
vote
1answer
124 views
Returning functions within Javascript objects
After coming across Douglas Crockford's views on class-free OOP, and doing away with new and this in Javascript I tried defining an object with its own variable and function, and returning it in a ...
0
votes
1answer
82 views
Question(s) about PHP PDO connections
Let's say I have a Db class [ db.php ] :
<?php
class Db
{
// class properties
private $db_driver = ''; // dsn credentials
private $db_dhost = '';
private ...
24
votes
7answers
3k views
How to return warnings alongside result of calculation to caller of a Java method? [duplicate]
I have a class, lets call it Calculator, with a method like this:
public double[] performCalculation(double[] someInData)
This method can generate a number of non fatal warnings (represented as an ...
1
vote
0answers
97 views
Making code more “modular”
As an semi-experienced procedural PHP developer, my OOP still needs a lot of work. I am still working through SOLID principles and other theories and guidelines of OOP, and am stuck with something ...
0
votes
2answers
71 views
What are 'good' cases for subtype overloads
To explain what I mean, I'm going to give an example of a bad case for a subtype overload.
Let's say we have a community of people. And depending on what kind people are in our community, our ...
-1
votes
0answers
62 views
Design approach for multi-shape graph nodes drawing
I am using Qt C++ to draw graph which represent and electronic circuit. The problem is that not all nodes have the same shape, I have 2 kind of nodes (circle, polygon), there is an edge class and node ...
27
votes
5answers
5k views
Is overriding concrete methods a code smell?
Is it true that overriding concrete methods is a code smell? Because I think if you need to override concrete methods:
public class A{
public void a(){
}
}
public class B extends A{
...
4
votes
4answers
291 views
Should an object be able to represent itself across components?
I'm working on a networked game. I have tried to design the various components (client, server, engine) to only about things within their domain. For example, the server should only be concerned with ...
0
votes
1answer
81 views
Design Pattern for Object Updates
I have a "Product" class that has some ID, and multiple other fields, and a function updateProduct(id, Product update). The intention is that "update" only contains the changed information - other ...
-1
votes
3answers
135 views
Modularity vs Polymorphism (OOD main concepts)
Booch gives 4 main concepts (principles) of OOD (see his book Object-oriented analysis and design with applications ):
Abstraction
Encapsulation
Modularity
Hierarchy
Usually we encounter to these ...
0
votes
2answers
230 views
Without using Singletons, what is a good way to manage a global resource? [duplicate]
Unlike many libraries SDL and OpenGL are designed to provide global resources; you can access them at any time from any class. There are justifications for this: They are written in C, meant to be ...
1
vote
1answer
101 views
Should “magic” getter functions be used for dynamically calculated values or just existing properties?
For example, if I had a Customer class and wanted to get all orders by them. Would it be better to do:
class Customer{
public function getOrders(){
return results from db query
}
}
...
1
vote
3answers
189 views
Can the circle-ellipse problem be solved by reversing the relationship?
Having Circle extend Ellipse breaks the Liskov Substition Principle, because it modifies a postcondition: namely, you can set X and Y independently to draw an ellipse, but X must always equal Y for ...
-2
votes
3answers
176 views
Is it possible to have private or protected objects in Java? Or are all objects considered public?
Is it possible to have private objects? For example, when you instantiate an object (classType object1 = new classType()), can that be private or protected or is it always public?
0
votes
1answer
65 views
How do you write super() in the UML format?Is it correct to write super(parameter: type): return type in the UML methods section?
Suppose you write a subclass that extends to a certain class and in that subclass, you use the super() method for your constructor.
Would you write "super(parameter: type): return type" in the UML?
2
votes
1answer
206 views
For Object Oriented Programming purists, are @annotations heresy?
Philosophical Question:
An issue that occurred to me is that especially when using frameworks like Spring or Hibernate ( which are everywhere in industry), we have annotate everything.
This is ...
-3
votes
2answers
59 views
How to allow Object creation of a class on only particular classes in PHP? [closed]
In PHP, let there be four classes A, B, C, and D. None of them inherits the other. They are all independent classes. Now, I want only B and C to be able to create Objects of the class A. D Should not ...
5
votes
6answers
267 views
Rule of thumb for deciding which class a method belongs to
For example, imagine a website which stores results about a certain sport or game, which has a typical "season" structure, such that there's both a Player and a Season class. To retrieve a player's ...
0
votes
1answer
69 views
Design patterns for ERP software with clients and web service
I'll will make ERP software for managing data for business activities. The solution must have two big parts: a WPF application for all the clients and an ASP MVC Web API application for all the ...
6
votes
3answers
350 views
Best practices for using public, protected, private?
Is it fair to say that it is good practice to default everything to private up front when coding something?
And then only upgrade it to protected if a subclass needs it, or public if another class ...
0
votes
1answer
94 views
How to store state data when the data is related to another entity?
In order to increase the parallel-ability of my objects, I try to make them read-only and include only data that naturally belong to the entity. I have
class Object { ... };
class Processor {
...
7
votes
3answers
505 views
Should every object know how to present/draw themselves?
David West in his book Object Thinking (chapter 10, section 1, sub-section 2) proposed that in an ideal OO environment, every objects should be capable of presenting themselves upon request; be it to ...
1
vote
2answers
74 views
Is it good design to log something related to an object from the callee?
I am designing a class whose object is instaniated with a user idn which creates a pdf with that user specific details. It should log something depending on success or failure which can be determined ...
