Something keeps showing up in my programming, and it is that two things are the same from some viewpoint, but different from another. Like, imagine you build a graph of rail stations, connected by trains, then the classes Vertex and RailStation are sometimes the same, other times not. So, imagine I have a graph that very much represent...
I'm using BulkLoader to load an array of 10 or so FLV files. I want to be able to use and control these FLVs throughout my app independently. So for instance, FLV_1 may be displayed in duplicate but I want to pause one instance and play the other in tandem. I would like to pass the NetStream object around to other Video objects and di...
Let's start from another behavior: even if you declare method/variable as private, another instance of the same class can access it. It's OK I can live with it. I call these class private and not instance private. Now the question part: For example, in runtime I want to be able to check that all String variables in this class are not nu...
I have a Contact class that contains a PortalAccount object. When I want to create a "Portal Account" for a contact, an account is created remotely on a portal application using soap/axis and then the contact's portalAccount is populated and the contact is saved (local database holds information about the remote account, like user id an...
If I have limited time, but I want to start learning a few design patterns, which ones should I learn first? ...
I'm training a Junior developer. I would like to assign him with the task of designing and building an object oriented application. Are there any non-trivial sample exercises on the web which include good description of a problem and a suggested architecture diagram? ...
NOTE: Sorry for the long question! I'm trying to understand some key areas behind object orientation and I couldn't decide one way or another about my particular question. Let's say I have an object full of lovely data. Class bob. Bob myBob = new Bob("This string is data"); Let's say I want to save the contents of myBob to an xml f...
Hi all Trust me, I've put a lot of thought into this problem before asking here, and I think I got a solution, but I'd like to see what you guys can come up with before settling for my own :) SCENARIO: In the domain we got 3 entities: A treatment, a beautyshop and an employee. A beautyshop can hire 0 to many employees. Now, a beautysa...
I guess the question title sums it up. Is there a time when it would be considered good design for an ABC to have data members? I have been wondering if there is a situation where this is OK. The only ones I can come up with all are static, and even then it's kind of a stretch. ...
Hi all, On page 175, there is an example of Chocolate Boiler class. Something like this: public class ChocolateBoiler { private boolean empty; private boolean boiled; public ChocolateBoiler { empty = true; boiled = false; } // and then three methods to fill, drain and boil which changes the // status...
Consider this - a base class A, class B inheriting from A, class C inheriting from B. What is a generic way to call a parent class constructor in a constructor? If this still sounds too vague, here's some code. class A(object): def __init__(self): print "Constructor A was called" class B(A): def __init__(self): ...
Suppose I have a class like this, in pseudo-code: public class someClass { public void doSomething() { someClass aux = new someClass(); // here something is done to alter the internal structures of aux . . this = aux; } } The attribution "this = aux", would return an error since it's no...
I'm finding myself coding a big project in Javascript. I remember the last one was quite an adventure because hacky JS can quickly becomes unreadable and I want this code to be clean. Well, I'm using objects to construct a lib, but there are several ways to define things in JS, implying important consequences in the scope, the memory ma...
Instead of using an interface like this: public interface IStartable { void Start(); void Stop(); } I usually just make the constructor of an object run the Start() code, and implement IDisposable so that the dispose method runs the Stop() code. Is it just a matter of style? Or am I missing something important by not having s...
Imagine an interface with a method to create objects of type Address. The entities involved here are irrelevant. /** * @throws IllegalArgumentException if addy is null or invalid * @throws PersistenceException if db layer encounters a problem */ Object addAddress( Address addy ); addAddress inserts the domain object into the databa...
What are some apraoches i can take to rewrite fairly large procedural php roughly 2000 lines of code app as an oo app. And should i even try to do so, or should i build on top of the existing app? I wrote it when i was learning programming and i now i want to expand it. ...
What is the advantage of having this/self/me pointer mandatory explicit? According to OOP theory a method is supposed to operate mainly (only?) on member variables and method's arguments. Following this, it should be easier to refer to member variables than to external (from the object's side of view) variables... Explicit this makes it...
Hi fellow Pythonistas, I have a question concerning subtypes of built-in types and their constructors. I want a class to inherit both from tuple and from a custom class. Let me give you the concrete example. I work a lot with graphs, meaning nodes connected with edges. I am starting to do some work on my own graph framework. There is ...
I am writing a simple graphic editor for a university project using C#. I created a hierarchy where every type of shape - circles, rectangles, ellipses, ... - are inherited from a base class Shape, it contains a shape color as a protected field. public abstract class Shape { protected Color color; public Shape(Color c)...
Ok, the question might not be crystal clear. Let me give some details: Let's say I have an Shoe (CShoe) object factory class called CFactory. CFactory is a singleton class that creates and stores all instanciated shoes using a simple hashmap. It is then accessed through static methods to use the created objects. Is there a way to force...