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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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, ...
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1answer
230 views

Names for generic classes - how to avoid naming them just “object”? Use synonyms?

When programming, I often end up naming some generic class (think of an abstract base class for stuff you manage in your project) something like FooObject, FooComponent or FooItem (where Foo is an ...
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2answers
542 views

Object-Oriented design and proper Java architecture for my program

This is the very first time that I think I want to create a program which really uses OOP principles and I want to do it in the most effective and efficient way. First of all we are given this (great)...
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2answers
199 views

Handling “unspecified” values in software

So I'm working on a software product where we have a number of fields that the customer can leave blank, some of which are numeric. To persist these in the database we use nullable columns. Easy peasy....
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8answers
4k views

Are classes with only a single (public) method a problem?

I am currently working on a software project that performs compression and indexing on video surveillance footage. The compression works by splitting background and foreground objects, then saving the ...
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3answers
233 views

A pattern to “atomically” update a pair of objects

Is there a standard pattern in OOP to kind of "atomically" update a pair of objects, like a pair of bank accounts on a transaction? I would like to have somehow a single public method exposed that ...
2
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2answers
627 views

C# Design Issue [closed]

I am building a small application and I am trying to understand the best way to approach the design. I am looking for some guidance/advice how best to approach the following issue. What I have is ...
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2answers
229 views

How to remove redundant code that enables button. Or “if” statement

I got probably "micro optimization" problem. I got "History number", "Next Number", "Reset" buttons, as well "label" for text. Every time I click At "Next number" button I would like to show random ...
2
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3answers
148 views

Refactor an old model of a LastUser Modification on every Object?

I have a software requirement, that needs to store the user that made the last modification to another object, for every object (assume that all objects are already mapped and into a BD). So we have ...
2
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1answer
611 views

What kind of object relational mapping is appropriate here?

In my database I have a table that looks like this Master(ID, Name, Attr1...). Every ID will have at least 1 entry in additional tables that have additional attributes. Those tables specialize the ...
2
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1answer
98 views

Are there any known effects on cognitive load of many files with one file per object?

There has been a trend in the Ruby/Rails community to create lots of objects that have very small functionality (SRP anyone?) and live in their own file. These are often extracted from large, bloated ...
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10answers
7k views

Can we live without constructors?

Let's say in some reason all objects are created this way $obj = CLASS::getInstance(). Then we inject dependencies using setters and perform starting initialization using $obj->initInstance(); Are ...
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2answers
616 views

How to handle status integers from database in object oriented code?

Consider a database table of Items that have a status flag represented by an integer. A few of the status might be: 0 - Past Storage; 1 - Current Inventory; 5 - Scrap; 6 - Rework; 15 - Processing; ...
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3answers
232 views

Benefits of using config files over making many small classes?

My friend and I are building a mobile game and ran into the following design problem: We will have many different types of units all with different stats and abilities. However, all unit types ...
3
votes
1answer
222 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 ...
3
votes
3answers
192 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 ...
8
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2answers
5k 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
777 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
184 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
342 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
369 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 ...
14
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5answers
3k 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
313 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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2answers
2k 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, ...
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1answer
679 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
2k 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 ...
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4answers
508 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 ...
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4answers
618 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 ...
2
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4answers
1k views

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

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
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4answers
1k 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, ...
54
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10answers
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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 ...
5
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3answers
518 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 ...
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3answers
383 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
570 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? ...
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3answers
234 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 ...
6
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4answers
817 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 ...
13
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1answer
9k 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 ...
12
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4answers
1k 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
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2answers
290 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 ...
5
votes
4answers
1k 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 ...
4
votes
1answer
144 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
96 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: ...
2
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2answers
942 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 ...
56
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3answers
13k 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 ...
22
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7answers
2k 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
695 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
324 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 ...
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1answer
182 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
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2answers
1k 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. Let'...
2
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0answers
366 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 ...