oop

Exporting a non public Type through public API

I am trying to follow Trees tutorial at: http://cslibrary.stanford.edu/110/BinaryTrees.html Here is the code I have written so far: package trees.bst; import java.util.ArrayList; import java.util.List; import java.util.StringTokenizer; /** * * @author sachin */ public class BinarySearchTree { Node root = null; class Node ...

PHP Object References in Frameworks

Before I dive into the disscusion part a quick question; Is there a method to determine if a variable is a reference to another variable/object? (Just want to check I am passing references around correctly and not make duplicate versions of my objects). For example $foo = 'Hello World'; $bar = &$foo; echo (is_reference($bar) ? 'Is refe...

PHP MVC Framework Structure

I am sorry about the amount of code here. I have tried to show enough for understanding while avoiding confusion (I hope). I have included a second copy of the code at Pastebin. (The code does execute without error/notice/warning.) I am currently creating a Content Management System while trying to implement the idea of Model View Co...

How do I call functions of an object inside the same object?

I have the following Javascript code add_num = { f: function(html, num) { alert(this.page); }, page : function() { return parseInt(this.gup('page')); }, gup : function(name) { name = name.replace(/[\[]/,'\\\[').replace(/[\]]/,'\\\]'); var regex = new RegExp('[\\?&]'+name+'=([^&#]*)'); var results = regex....

How to determine which inheriting class is using an abstract class's methods.

In my console application have an abstract Factory class "Listener" which contains code for listening and accepting connections, and spawning client classes. This class is inherited by two more classes (WorldListener, and MasterListener) that contain more protocol specific overrides and functions. I also have a helper class (ConsoleWra...

Parametrized Strategy Pattern

I have several Java classes which implement the strategy pattern. Each class has variable number parameters of different types: interface Strategy { public data execute(data); } class StrategyA implements Strategy { public data execute(data); } class StrategyB implements Strategy { public StrategyB(int paramA, int par...

learning OO with PHP

Hi there I've started to learn OO programming, but using the PHP language with the help of the "PHP 5 Objects, Patterns, and Practice" book. The thing is that I wish to learn to use into same time the CakePHP framework which make use a lot of the MVC pattern. Because I don't know much about OO and less about MVC I wish to understand the...

Dependency Injection & Singleton Design pattern

How do we identify when to use dependency injection or singleton pattern. I have read in lot of websites where they say "Use Dependency injection over singleton pattern". But I am not sure if I totally agree with them. For my small or medium scale projects I definitely see the use of singleton pattern straightforward. For example Logger...

Trouble with inheritance

I'm relatively new to programming so excuse me if I get some terms wrong (I've learned the concepts, I just haven't actually used most of them). Trouble: I currently have a class I'll call Bob its parent class is Cody, Cody has method call Foo(). I want Bob to have the Foo() method as well, except with a few extra lines of code. I've at...

Is method hiding ever a good idea

In C# the new modifier can be used to hide a base class method without overriding the base class method. I've never encountered a situation where hiding a method was the best choice available. Are there any situations where method hiding is the best choice? ...

Learning to write organized and modular programs

I'm a computer science student, and I'm just starting to write relatively larger programs for my coursework (between 750 - 1500 lines). Up until now, it's been possible to get by with any reasonable level of modularization and object oriented design. However, now that I'm writing more complex code for my assignments I'd like to learn to...

Socket server with multiple clients, sending messages to many clients without hurting liveliness

I have a small socket server, and I need to distribute various messages from client-to-client depending on different conditionals. However I think I have a small problem with livelyness in my current code, and is there anything wrong in my approach: public class CuClient extends Thread { Socket socket = null; ObjectOutputStream out; ...

how to do validations when composing object of a class in other class ?

Hi, I have an IPAddress class which has one property named ip and in its setter I am validating data coming and if data is invalid it throws an error. (Its code is as the following): private string ip; public string IP { get { return ip; } set { string PartsOfIP = value.Split('.'); if (PartsOfIP.Length == 4) { foreach (st...

What should layers in dotnet application ?

I am using layered architecture in dotnet (mostly I work on web projects). I am confuse what layers should I use ? I have small idea that there should be the following layers. user interface customer types (custom entities) business logic layer data access layer My purpose is sure quality of work and maximum re-usability of code. ...

How much abstraction is too much?

In an Object Oriented Program: How much abstraction is too much? How much is just right? I have always been a nuts and bolts kind of guy. I understood the concept behind high levels of encapsulation and abstraction, but always felt instinctively that adding too much would just confuse the program. I always tried to shoot for an amoun...

Compilation Error: "The modifier 'public' is not valid for this item" while creating public method on a class for explicitly implementing the interface.

I am getting this error while creating public method on a class for explicitly implementing the interface. I have the workaround: by removing the explicit implementation of PrintName Method, But surprised why i am getting this error. Can anyone explain the error. Code for Library: using System; using System.Collections.Generic;...

Pattern for iPhone background loading during init?

Hi everyone, I'm currently kicking off a background thread to do some REST queries in my app delegate's didFinishLaunchingWithOptions. This thread creates some objects and populates the model as the rest of the app continues to load (because I don't block, and didFinishLaunchingWithOptions returns YES). I also put up a loading UIViewC...

Using generics with XmlSerializer

Hi, When using XML serialization in C#, I use code like this: public MyObject LoadData() { XmlSerializer xmlSerializer = new XmlSerializer(typeof(MyObject)); using (TextReader reader = new StreamReader(settingsFileName)) { return (MyObject)xmlSerializer.Deserialize(reader); } } (and similar code for deserializ...

what does "domain" and "persistence" mean?

i always encounter these 2 words. i know that when you are talking about domain model you are talking about objects. and persistence layer is a layer you store your data, eg. mysql database. but could someone explain these words more thoroughly? why is it called domain? why persistence? thanks! ...

Object oriented design of game in Java: How to handle a party of NPCs?

Hi folks, I'm making a very simple 2D RPG in Java. My goal is to do this in as simple code as possible. Stripped down to basics, my class structure at the moment is like this: Physical objects have an x and y dimension. Roaming objects are physical objects that can move(). Humanoid objects are roaming objects that have inventories ...