Object-oriented design is the process of planning a system of interacting objects for the purpose of solving a software problem.

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1answer
158 views

How can I structure my code when I have orthogonal arrays of features?

Example: You have a game with different schools of magic (fire, ice, etc). Each school has a set of properties that pertain to independent features of the game, such as: strings to be displayed on ...
2
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2answers
69 views

How do I recreate this Access Control/Group/ whatever methodology in OO/MVC

I am looking at trying to rewrite an application that is mostly procedural to an MVC/OO approach in order to teach myself a deeper understanding of both. BUT, I am having some conceptual issues with ...
5
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2answers
481 views

Open Close Principle (OCP) vs Dependency Inversion Principle (DIP)

I was trying to understand the difference between Open Closed Principle (OCP) and Dependency Inversion Princible (DIP). Based on research I've made on the internet so far, I came to the conclusion ...
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3answers
122 views

Service method, bean as an argument and mandatory attributes

There is a service: createUser(User user) where you can create a new user, with so many attributes (name, address lines...). Now, some user attributes are mandatory. Other attributes are not ...
0
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1answer
135 views

Boolean properties in Class A control availability of members in Class B: Design Pattern?

Given the following code: class AnimalDescriptor { String species; boolean hasLegs; boolean hasTeeth; boolean hasHair; public AnimalDescriptor(String species, boolean hasLegs, ...
0
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1answer
229 views

Flexible / Dynamic object creation or Alternative to list of lists [closed]

I have a xlsx file, that has some tabs with different data. I want to be able to save each row of a tab in a list. The first thing that comes to mind is a list of lists, but I was wondering if there ...
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3answers
215 views

Add behavior without changing existing class

I have a class Container, which represents wrapper around std::list. This class contains following public methods: void add(Shape *item) void next() void setBegin() Shape* curr() and protected ...
13
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6answers
2k views

Should a class know about its subclasses?

Should a class know about its subclasses? Should a class do something that is specific for a given subclass for instance? My instincts tells me that is a bad design, it seems like an anti-pattern of ...
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3answers
293 views

Problems with Facades and then evolution in software

I initially started a project with Facades and Polymorphism as a way to create simple extensible design following SOLID Principles. Here is a sample code: public interface IInterface { void ...
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0answers
260 views

JavaScript Class Module: How to avoid an antipattern

I've seen a number of different methodologies when it comes to applying class-based inheritance to JS/ECMA-based projects. Over the past several months, I've been applying IIFE Namespaces to my class ...
5
votes
2answers
445 views

What is the difference between self-types and trait inheritance in Scala?

When Googled, many responses for this topic come up. However, I don't feel like any of them do a good job of illustrating the difference between these two features. So I'd like to try one more time, ...
1
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1answer
252 views

Interface Dependencies or Abstract Classes

I have a decision to make and I am wondering what would be the better solution. I am refactoring an older application and intend to really get into the nuts and bolts of it. There are 8 report types ...
0
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3answers
364 views

Requirement gathering and use cases examples [closed]

I've heard a lot about requirement gathering and use cases in theory, but in practice often happens that we ask ourselves "should we include this? should this be a use case? in which language should ...
4
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4answers
298 views

How would you model an objects representing different phases of an entity life cycle?

I believe the scenario is common mostly in business workflows - for example: loan management the process starts with a loan application, then there's the loan offer, the 'live' loan, and maybe also ...
7
votes
4answers
291 views

Is throwing an error in unpredictable subclass-specific circumstances a violation of LSP?

Let's say I wanted to create a Java List<String> (see spec) implementation that uses a complex subsystem, such as a database or file system, for its store so that it acts as a persistent ...
1
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4answers
461 views

Explanation needed, for “Ask, don't tell” approach?

I'm taking a course on design patterns in software engineering and here I'm trying to understand the good and the bad way of design relating to "coupling" and "cohesion". I could not understand the ...
8
votes
4answers
721 views

How do we keep dependent data structures up to date?

Suppose you have a parse tree, an abstract syntax tree, and a control flow graph, each one logically derived from the one before. In principle it is easy to construct each graph given the parse tree, ...
47
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10answers
2k views

What is meant by, “A user shouldn't decide whether it is an Admin or not. The Privileges or Security system should.”

The example used in the question pass bare minimum data to a function touches on the best way to determine whether the user is an administrator or not. One common answer was: user.isAdmin() This ...
4
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3answers
201 views

How to conciliate OOAD and Database Design?

Recently I've studied object oriented analysis and design and I liked a lot about it. In every place I've read people say that the idea is to start with the minimum set of requirements and go ...
0
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3answers
243 views

When should method overloads be refactored?

When should code that looks like: DoThing(string foo, string bar); DoThing(string foo, string bar, int baz, bool qux); ... DoThing(string foo, string bar, int baz, bool qux, string more, string ...
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4answers
411 views

Does it make sense to generate java classes from class diagram?

As we do design & analysis before development, wouldn't be convenient to be able to generate Java classes from a class diagram? This would promote more exhaustive design and better codes, right? ...
1
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3answers
157 views

Law of Demeter in MVC regarding Controller-View communication

The scenario: Having a Controller that controls a view composed of complex subviews. Each one of those subviews is a separated class in a separate file. For example, one of those subviews is called ...
3
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4answers
505 views

Are trivial protected getters blatant overkill?

Something I really have not thought about before (AS3 syntax): private var m_obj:Object; protected function get obj():Object { return m_obj; } private var m_str:String; protected function get ...
6
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1answer
1k views

Understanding Visitor Pattern

I have a hierarchy of classes that represents GUI controls. Something like this: Control->ContainerControl->Form I have to implement a series of algoritms that work with objects doing various ...
13
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4answers
625 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 ...
2
votes
2answers
194 views

How to structure my GUI agnostic project?

I have a project which loads from database a XML file which defines a form for some user. XML is transformed into a collection of objects whose classes derive from single parent. Something like ...
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4answers
442 views

How do I decide to which class a method should belong

I have TopicBusiness.class and PostBusiness.class. I have no problem with deciding into which class methods such as addPostToDatabase() or getAllPostsFromDatabase() should go. But what about ...
3
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1answer
97 views

Is avoiding the private access specifier in PHP justified?

I come from a Java background and I have been working with PHP for almost a year now. I have worked with WordPress, Zend and currently I'm using CakePHP. I was going through Cake's lib and I couldn't ...
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1answer
93 views

Proper library for enums

I'm trying to refactor some code such that the display is separate from the implementation, and I'm not sure where to put the existing enums. My project is currently structured as follows: ...
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2answers
369 views

Dependency injection with Finite State Machines and the Interface Segregation Principle

I am trying to figure out what is the best way to setup a FSM and also keep my interfaces clean and use an IOC container to use DI. Let's just visit the Head First design pattern textbook example of ...
23
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3answers
3k views

Rich Domain Models — how, exactly, does behavior fit in?

In the debate of Rich vs. Anemic domain models, the internet is full of philosophical advice but short on authoritative examples. The objective of this question is to find definitive guidelines and ...
17
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7answers
1k views

Does functional programming ignore the benefits gained from the “On the Criteria To Be Used in Decomposing Systems into Modules” (data hiding)?

There's a classic article named On the Criteria To Be Used in Decomposing Systems into Modules that I just read for the first time. It makes perfect sense to me, and is probably one of those articles ...
4
votes
2answers
540 views

How much logic can be put into an object-pooling factory class before it does more harm than good?

The main language I'm interested in doing object pooling in is AS3, which is known to need it in many cases. In the past I've always made a brand new factory class for every type I was going to try ...
3
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3answers
302 views

Making some methods mostly contain method calls, while others doing “the lowest level” work [duplicate]

So I thought about this, and I don't know if it's included or not in any methodology. I think the advantages of this coding style is that, at the lowest level, the code is extremely testable, and ...
1
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1answer
163 views

When should one use composition instead of re-writing the functionality?

Say, I have a class A which has methods m1,m2,m3,m4,m5.... m100. I am making another simpler class B and I require only m2,m3 and m5 in B. Should I be ideally using compositions and put a reference ...
2
votes
2answers
423 views

OOP Objects, nested objects, and DAO's

Here's something I keep struggling to figure out the best solution to. I've had this problem while working with PHP and Java so it's a fundamental understanding of OOP issue. Examples are in PHP. ...
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0answers
138 views

How should Object Model wrapper classes behave when underlying objects are deleted?

I'm currently building an object model library for use in a project. It wraps our internal concepts - Servers, Folders, Items - in an object hierarchy (IFolder, IItem, etc), and we have several ...
3
votes
2answers
155 views

How do I alter an open source library for my own use?

I'm programming in Objective-C. I want to include a camera library, DLCImagePicker, in my project. There is a variable I need to change, but it is private and I have no access to it. I've thought of ...
5
votes
3answers
303 views

How should I create a combined interface for two logically independent modules?

I'm having trouble coming up with a good way to structure the interfaces for two modules that are logically independent but whose implementations may be combined for the purposes of performance or ...
1
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2answers
184 views

Pattern / methodology for representing large database records as objects

A bit of background information: We have an old database application written in Access that lets users monitor their workload, and the code is... 'procedural' might be too kind. The vast majority of ...
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2answers
329 views

A better alternative to incompatible implementations for the same interface?

I am working on a piece of code which performs a set task in several parallel environments where the behaviour of the different components in the task are similar but quite different. This means that ...
1
vote
4answers
456 views

How to get Object Oriented Programming Concepts? [closed]

What is the best way or best resources or tutorials to learn Object Oriented Programming? For instance, when I begin a program with Java and all my code goes into just one class and I can't estimate ...
0
votes
3answers
251 views

Liskov substitution principle when implementing two unrelated interfaces

Suppose I have two unrelated interfaces with the same method: interface Table { /** * @param width (0 < width <= 100) */ void setWidth(int width); } interface Square { ...
4
votes
5answers
705 views

What is the name of this particular kind of over-engineering? [closed]

When faced with (even a small) project, I tend to fall into the following bad practice. I think about the structure of the problem. Then I create some base classes, derive from them and then derive ...
1
vote
3answers
150 views

Force user to extend class or use configuration

What is better practice: force user to extend abstract class or make class with configuration? Eg. pseudocode: ClassA{ this.name this.weight this.height this.width constr(config){ this.name = ...
0
votes
1answer
171 views

Architecting Domain Layer and other modules with dependency injection in mind

I am currently new to Dependency Injection pattern. I am influenced by link by Mark Seemann. I have a confusion regarding whether an interface for an agent class of some agent module should be ...
0
votes
6answers
548 views

What are the reasons to create UIView subclass?

I've noticed that there are a lot of UIView subclasses in my legacy project. Mostly the only reason of such a subclass is to split bigger view into custom subviews and provide layout for its subviews ...
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1answer
85 views

How much time should be spent with use cases?

I'm starting to work with agile iterative approach to software development and this question seems quite natural. After gathering the requirements I should write a few use cases to describe how the ...
0
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3answers
150 views

Deciding how to model customer when it can be both natural and legal person

Suppose that we are developing some application that requires us to be able to manage customers and that those customers can be both natural and legal person. There are some different ways on which we ...
2
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2answers
316 views

Is this a good use case?

I've been studying object oriented analysis and, so to get started with this in practice I've decided to first of all build my own management system to have my customers data and so on. Trying to ...