class-design

USE case to Class Diagram - How do I?

Hi, I would like your guidance on how to create classes and their relationships (generalization, association, aggregation and composition) accurately from my USE case diagram (please see below). I am trying to create this class diagram so I can use it to create a simple online PHP application that allows the user to register an accoun...

UML Class Relationships

Hi, I would like to confirm whether I am on the right track when identifying common UML class relationships. For example, is the relationship between: 1 a stackoverflow member and his/her stackoverflow user account categorized as a composition relationship or an aggregation relationship? At first I thought it was an association because ...

UML Class Diagram for User Login

Hi, The diagram below is my very first attempt at creating a UML class diagram describing a user login into a website. I'm sure its a poor design and full of flaws, but I'm hoping to learn from you guys how you would design a simple login like this. I'm particularly interested in your use of design patterns and which patterns you woul...

Best approach for OOP Class relationship design

I have got a designing dilema. I have a class named UserAccount that represent a user that has the ability to log into a school system and access information like the courses he/she is taking, avatar, news, etc. Then there is another class named Course that represents any course given in this school. It holds information like the amount ...

Factory pattern vs ease-of-use?

Background, I am extending the ASP.NET Membership with custom classes and extra tables. The ASP.NET MembershipUser has a protected constructor and a public method to read the data from the database. I have extended the database structure with custom tables and associated classes. Instead of using a static method to create a new member...

How to "wrap" implementation in C#

Hello, I have these classes in C# (.NET Framework 3.5) described below: public class Base { public int State {get; set;} public virtual int Method1(){} public virtual string Method2(){} ... public virtual void Method10(){} } public class B: Base { // some implementation } public class Proxy: Base { private B _...

IList<Item> Collection Class accessing database

Hi, I have a database with Users. Users have Items. These Items can change actively. How do you access the items in a collection type format? For the user, I fill all the user properties at the time of instantiation. If I load the user's items at the time of the instantiation, and the items change, they will have old data. I was think...

Is it good to subclass a class only to separate some functional parts?

Suppose we have abstract class A (all examples in C#) public abstract class A { private Foo foo; public A() { } public void DoSomethingUsingFoo() { //stuff } public void DoSomethingElseUsingFoo() { //stuff } //a lot of other stuff... } But we are able to split it into two classes...

RPG Game loop and class structure (cocos2D for iPhone)

I'm looking to make an RPG with Cocos2D on the iPhone. I've done a fair bit of research, and I really like the model Cocos2D uses for scenes. I can instantiate a scene, set up my characters etc. and it all works really nicely... what I have problems with is structuring a game loop and separating the code from the scenes. For example, wh...

How can I modify my classes to use it's collections in WPF TreeView

Hello, i'am trying to modify my objects to make hierarchical collection model. I need help. My objects are Good and GoodCategory: public class Good { int _ID; int _GoodCategory; string _GoodtName; public int ID { get { return _ID; } } ...

Access variables from a number of sources

I'm creating my first game, and I've currently set up a 'GameState' class, to store player health etc. inside. This class is currently instantiated from the AppDelegate as I need to access it from all over my game. This is fine. For each class I'm working in, I can access the app delegate, and then find the GameState object... however, ...

Howto write a class where a property can be accessed without naming it.

I have a (dump) question regarding VB/C# I often use third party classes where I can access a child object with only specifying the id or key. Example: Instead of writing: DataRow row = GetAPopulatedDataRowSomeWhere(); Object result = row.Items[1]; // DataRow has no Items property Object result = row.Items["colName"]; // Also not pos...

this pointer to base class constructor?

I want to implement a derived class that should also implement an interface, that have a function that the base class can call. The following gives a warning as it is not safe to pass a this pointer to the base class constructor: struct IInterface { void FuncToCall() = 0; }; struct Base { Base(IInterface* inter) { m_inter = int...

Making Class methods instead of Instance Methods in VB.NET

I am not sure how clear my question is by the title, but I am trying to make Class methods instead of Instance methods in Visual Basic that way I don't have to waste memory and code creating temporary objects to execute methods that don't need instance variables. I am not sure if you can do that in VB but I know you can in Objective-C b...

How do I manipulate a tree of immutable objects?

I'm building an entire application out of immutable objects so that multi-threading and undo become easier to implement. I'm using the Google Collections Library which provides immutable versions of Map, List, and Set. My application model looks like a tree: Scene is a top-level object that contains a reference to a root Node. Each No...

How to design shape class

I want to design shape class. I need to distinguish several different shapes: -Point -Line -Triangle -Circle -Polygons The main purpose of this class is to calculate distance between two shapes. I've all methods for calculating those distances, but I want to have a single method that can be used, it should looks like this:...

In .NET, Why Can I Access Private Members of a Class Instance within the Class?

While cleaning some code today written by someone else, I changed the access modifier from Public to Private on a class variable/member/field. I expected a long list of compiler errors that I use to "refactor/rework/review" the code that used this variable. Imagine my surprise when I didn't get any errors. After reviewing, it turns out ...

Start thread with two parameters

I've got a method that gets called on an event, which presents me with two variables varA, varB (both strings). This method gets called with new information quite frequently, thus I have created a separate method that takes in the two parameters. I want to run this method in a thread, however have struck the issue that Thread.Start wil...

Is it better for class data to be passed internally or accessed directly?

Example: // access fields directly private void doThis() { return doSomeWork(this.data); } // receive data as an argument private void doThis(data) { return doSomeWork(data); } The first option is coupled to the value in this.data while the second option avoids this coupling. I feel like the second option is always better. It...

What all does a compiler add to an empty class declaration?

Suppose, I write class A { }; compiler should provide (as and when needed) a constructor a destructor a copy constructor = operator Is this all what the compiler provides? Are there any additions or deletions to this list? ...