I started out with a generic interface called ILogin. The interfaces requires that you implement two properties: UserID and Password. I have many login-type classes that implement this interface. As my project grew and grew, I found that many classes repeated the UserID and Password code. Now I decide that I need a base Login class. ...
Some background info; LanguageResource is the base class LanguageTranslatorResource and LanguageEditorResource inherit from LanguageResource LanguageEditorResource defines an IsDirty property LanguageResourceCollection is a collection of LanguageResource LanguageResourceCollection internally holds LanguageResources in Dictionary<string...
This is somewhat of a follow-up question to this question. Suppose I have an inheritance tree as follows: Car -> Ford -> Mustang -> MustangGT Is there a benefit to defining interfaces for each of these classes? Example: ICar -> IFord -> IMustang -> IMustangGT I can see that maybe other classes (like Chevy) would want to implement...
Consider this: public class TestClass { private String a; private String b; public TestClass() { a = "initialized"; } public void doSomething() { String c; a.notify(); // This is fine b.notify(); // This is fine - but will end in an exception c.notify(); // "Local variable c may not have been ...
We have a decent sized object-oriented application. Whenever an object in the app is changed, the object changes are saved back to the DB. However, this has become less than ideal. Currently, transactions are stored as a transaction and a set of transactionLI's. The transaction table has fields for who, what, when, why, foreignKey, a...
template <class M, class A> class C { std::list<M> m_List; ... } Is the above code possible? I would like to be able to do something similar. Why I ask is that i get the following error: Error 1 error C2079: 'std::_List_nod<_Ty,_Alloc>::_Node::_Myval' uses undefined class 'M' C:\Program Files\Microsoft Visual Studio 9.0\VC\include...
There are two schools of thought on how to best extend, enhance, and reuse code in an object-oriented system: Inheritance: extend the functionality of a class by creating a subclass. Override superclass members in the subclasses to provide new functionality. Make methods abstract/virtual to force subclasses to "fill-in-the-blanks" when...
I have a code: class AbstractQuery { virtual bool isCanBeExecuted()=0; public: AbstractQuery() {} virtual bool Execute()=0; }; class DropTableQuery: public AbstractQuery { vector< std::pair< string, string> > QueryContent; QueryValidate qv; public: explicit DropTableQuery(const string& qr): AbstractQuery(), qv(q...
I control access to some of my static web resources with some PHP logic. Because directory-based authorization through the webserver is not suitable or easily possible. A combination of things determines whether access is granted or denied. And these rules change from time to time. In the beginning it was a simple regex path match, a...
I am trying to learn Python and WxPython. I have been a SAS programmer for years. This OOP stuff is slowly coming together but I am still fuzzy on a lot of the concepts. Below is a section of code. I am trying to use a button click to create an instance of another class. Specifically-I have my main panel in one class and I wanted to...
Given a class instance, is it possible to determine if it implements a particular interface? As far as I know, there isn't a built-in function to do this directly. What options do I have (if any)? ...
Generally I connect and retrieve data using the standard way (error checking removed for simplicity): $db = mysql_select_db("dbname", mysql_connect("host","username","passord")); $items = mysql_query("SELECT * FROM $db"); while($item = mysql_fetch_array($items)) { my_function($item[rowname]); } Where my_function does some useful ...
What would be the best way to manage large number of instances of the same class in MATLAB? Using the naive way produces absymal results: classdef Request properties num=7; end methods function f=foo(this) f = this.num + 4; end end end >> a=[]; >> tic,for i=1:1000 a=[a Request];en...
I've been studying OOP for quite a while now and I have a good grasp of the theory. I read the Head First book on OOP and, while it reinforced a lot of the theory, I found the case studies to be somewhat trivial. I find that I'm applying OOP principles to my code each day, but I'm not sure if I'm applying them correctly. I need to get...
It's easy to wrap optional memcached caching around your existing database queries. For example: Old (DB-only): function getX x = get from db return x end New (DB with memcache): function getX x = get from memcache if found return x endif x = get from db set x in memcache return x end The th...
Or should they always be a function when business logic is invloved ? Example: Order.RequiresPayment property or function ? There are business rules as for when it is true or not IS there a pattern that may determine this? ...
Hello! I have got two classes, one a subclass of the other (say Animal and Dog). The superclass has got some initializers (say initAnimal), the subclass has some initializers (say initDog). The problem is that it is perfecly legal (from the compiler’s viewpoint) to do something like Dog *adog = [[Dog alloc] initAnimal], ie. initialize a ...
I must confess I'm somewhat of an OOP skeptic. Bad pedagogical and laboral experiences with object orientation didn't help. So I converted into a fervent believer in Visual Basic (the classic one!). Then one day I found out C++ had changed and now had the STL and templates. I really liked that! Made the language useful. Then another day...
I'm going to try to ask my question in the context of a simple example... Let's say I have an abstract base class Car. Car has-a basic Engine object. I have a method StartEngine() in the abstract Car class that delegates the starting of the engine to the Engine object. How do I allow subclasses of Car (like Ferrari) to declare the En...
I'm relatively new to NHibernate, but have been using it for the last few programs and I'm in love. I've come to a situation where I need to aggregate data from 4-5 databases into a single database. Specifically it is serial number data. Each database will have its own mapping file, but ultimately the entities all share the same basic...