Tagged Questions
2
votes
2answers
103 views
Where should I parse data obtain with a DAO
I have a DAO that brings data from a web service, that data comes in a string, in the likes of:
*NAME|John Doe *DATEOFBIRTH|1978-23-01*ID|anID123 (...)
I have a DTO that I wanna fill up with the ...
3
votes
2answers
139 views
Are there any well-known quantitative approaches to evaluate a particular design whether it satisfies or violates the SOLID design principles? [duplicate]
I designed an application framework by considering the SOLID design principles and supported by design patterns. However, I wonder if there are any automated tools or well-known approaches to evaluate ...
2
votes
1answer
205 views
Best OOP design pattern for a sequence of operations
I am working on an application, a module of which does the following financial operations sequentially:
When a user requests for a certain amount to be transferred into her bank account:
check ...
0
votes
1answer
37 views
Program Structure for Table Cells Representing Objects
So I have a program with "cue" objects and each have their own table cell. The thing is that the table cells have loading bars on them that represent the progress of the cues. This presents the ...
1
vote
3answers
302 views
What is the difference between polymorphism and factory method? [closed]
Can I say that polymorphism is same as factory method?
EDIT: So basically I can say that a factory method is used to determine at run time which object is required whereas polymorphism already knows ...
0
votes
2answers
126 views
How to design member access for an Article-type class? [duplicate]
I am doing a final project in a C++ class writing a very simple usenet-like client/server. I figure that since it's usenet-like I'll have a NewsGroup class and an Article class, I'm now working on my ...
4
votes
2answers
227 views
Preventing Liskov Substitution violation
I am reimplementing some component and noticed that the original version has a Liskov Substitution violation. It's not all that critical, though I'd like to get rid of it in the new implementation . ...
2
votes
2answers
133 views
Changing __class__ in a factory?
I'm parsing a set of XML files of different kinds (these kinds are known in advance).
These are my requirements:
I want an object to represent each XML document (object-xml mapping)
I'd rather ...
3
votes
3answers
182 views
Visitor stability vs instanceof flexibility
I am writing on a GUI program which allows for the visual creation of some configuration file. I have a class hierarchy for the configuration model and I use an object tree of that hierarchy in ...
1
vote
1answer
71 views
How to get a reference to a central AssetLoader in every Widget?
I'm working on a simple UI system for a game. The building blocks are Widget objects, which can contain each other. There are several sub classes of Widget, e.g. LabelWidget, ImageWidgetand ...
2
votes
4answers
368 views
Good design pattern for a c++ wrapper around a c object
I have written an extensible c++ wrapper around a very hard to use but also very useful c library. The goal is to have the convience of c++ for allocating the object, exposing its properties, ...
0
votes
1answer
211 views
Liskov substitution and abstract classes / strategy pattern
I'm trying to follow LSP in practical programming. And I wonder if different constructors of subclasses violate it. It would be great to hear an explanation instead of just yes/no. Thanks much!
P.S. ...
3
votes
4answers
230 views
Representing complex object dependencies
I have several classes with a reasonably complex (but acyclic) dependency graph. All the dependencies are of the form: class X instance contains an attribute of class Y. All such attributes are set ...
1
vote
1answer
255 views
Use decorator and factory together to extend objects?
I'm new to OOP and design pattern.
I've a simple app that handles the generation of Tables, Columns (that belong to Table), Rows (that belong to Table and have Columns) and Values (that belong to ...
0
votes
1answer
117 views
would a composite design pattern be useful for group membership?
I'm trying to think about the best way to handle group memberships on a website. People sign up and select checkboxes in a list of interests. Every week we send out interest-themed emails to those ...
0
votes
2answers
148 views
When modeling a virtual circuit board, what is the best design pattern to check for cycles?
To make it simple assume you have only AND and OR gates. Each has two inputs and one output. The output of two inputs can be used as an input for the next gate For example:
A AND B -> E
C AND D -> F
...
5
votes
1answer
156 views
Object oriented wrapper around a dll
So, I'm writing a C# managed wrapper around a native dll. The dll contains several hundred functions. In most cases, the first argument to each function is an opaque handle to a type internal to the ...
10
votes
7answers
1k views
What can go wrong if the Liskov substitution principle is violated?
I was following this highly voted question on possible violation of Liskov Substitution principle. I know what the Liskov Substitution principle is, but what is still not clear in my mind is what ...
2
votes
1answer
137 views
How can I design my classes to include calendar events stored in a database?
I'm developing a web calendar in php (using Symfony2) inspired by iCal for a project of mine.
At this moment, I have two classes: a class "Calendar" and a class "CalendarCell".
Here you are the two ...
4
votes
3answers
276 views
What is a good design model for my new class?
I am a beginning programmer who, after trying to manage over 2000 lines of procedural php code, now has discovered the value of OOP. I have read a few books to get me up to speed on the beginning ...
1
vote
1answer
118 views
design pattern advice: graph -> computation
I have a domain model, persisted in a database, which represents a graph. A graph consists of nodes (e.g. NodeTypeA, NodeTypeB) which are connected via branches. The two generic elements (nodes and ...
2
votes
1answer
337 views
Design patterns and multiple programming languages
I am referring here to the design patterns found in the GOF book. First, how I see it, there are a few peculiarities to design pattern and knowing multiple languages, for example in Java you really ...
8
votes
7answers
708 views
Interfaces on an abstract class
My coworker and I have different opinions on the relationship between base classes and interfaces. I'm of the belief that a class should not implement an interface unless that class can be used when ...
6
votes
5answers
562 views
Open source software with good code documentation to improve design skill [closed]
As I'm trying to get better at designing good software I'm wondering if there are out there good (as in well written) open source software with lot of code documentation that aims to explain details ...
3
votes
4answers
470 views
When, Where, and How to Unit Test
I'm very familiar with xUnit frameworks and I try to implement unit tests on every project I start. Somewhere along the way, I realize that I'm writing the same tests over and over again, and then I ...
3
votes
2answers
222 views
Design suggestions needed to create a MathBuilder framework
Let explain what I'm trying to create. I'm creating a framework, the idea is to provide base classes to generate a math problem.
Why do I need this framework? Because at first time, I realized when I ...
31
votes
8answers
2k views
Is OOP becoming easier or harder?
When the concepts of Object Oriented Programming were introduced to programmers years back it looks interesting and programming was cleaner. OOP was like this
Stock stock = new Stock();
...
3
votes
7answers
731 views
Design patterns: moving object references around an application
I'm new to Programmers and I am looking to increase my knowledge of programming. Recently, a user on Stack Overflow told me using singletons is a bad idea, that they encourage tight coupling and that ...
5
votes
2answers
160 views
Adapter Pattern to expose different aspects of an object — Is this a correct use?
Quite frequently, I use an Adapter-like design to expose different aspects of data objects.
For example, in a 3D modelling application I use an object hierarchy to represent the 3d models in the ...
9
votes
3answers
445 views
Do I suffer from encapsulation overuse?
I have noticed something in my code in various projects that seems like code smell to me and something bad to do, but I can't deal with it.
While trying to write "clean code" I tend to over-use ...
0
votes
2answers
261 views
how should I design Objects around this business requirement?
This is the business requirement:
"
A Holiday Package (e.g. New York NY Holiday Package) can be offered in different ways based on the Origin city:
From New Delhi to NY
From Bombay to NY
NY itself ...
4
votes
4answers
209 views
How do I handle priority and propagation in an event system?
Let's say I have a simple event system with the following syntax:
object = new Object();
object.bind("my_trigger", function() { print "hello"; });
object.bind("my_trigger", function() { print ...
2
votes
1answer
882 views
Subscribe/Publish Model in Web-based Application (c#) - Best Practices for Event Handlers
I was recently exposed to a desktop application that uses an publish/subscribe model to handle commands, events, etc. I can't seem to find any good examples of using this in a web application, so I ...
3
votes
2answers
314 views
What are some good small-scale refactoring tests?
I'm looking to test potential candidates on their ability to develop concise, reusable code. I feel like a good test of that skill would be to give them a very small scale application or class ...
0
votes
1answer
298 views
Wrapping a 3rd party API - Gateway Pattern connections
Given a 3rd party API with a very cumbersome object with many different responsibilities-- we decide to wrap using small, manageable, single-responsibility objects. This is the gateway pattern (I ...
42
votes
15answers
7k views
Is it better to return NULL or empty values from functions/methods where the return value is not present?
I am looking for a recommendation here. I am struggling with whether it is better to return NULL or an empty value from a method when the return value is not present or cannot be determined.
Take ...
5
votes
1answer
109 views
Checking members and instantiating in properties
Consider this:
public MyClass
{
private Resource _myResource;
public Resource MyResource
{
get
{
if(_myResource == null)
{
...
0
votes
1answer
151 views
Designing classes containing the same objects but different amount of them
I am creating a main object, MACHINE, which will contain a diversity of several other objects -- AXIS, AMPLIFIER, ENDEFFECTOR, etc. The number of contained objects will vary depending on the MACHINE ...
5
votes
3answers
616 views
Duplication in parallel inheritance hierarchies
Using an OO language with static typing (like Java), what are good ways to represent the following model invariant without large amounts of duplication.
I have two (actually multiple) flavours of the ...
