design-patterns

New design patterns/design strategies

I've studied and implemented design patterns for a few years now, and I'm wondering. What are some of the newer design patterns (since the GOF)? Also, what should one, similar to myself, study [in the way of software design] next? Note: I've been using TDD, and UML for some time now. I'm curious about the newer paradigm shifts, and or ...

Design pattern question: encapsulation or inheritance

Hey all, I have a question I have been toiling over for quite a while. I am building a templating engine with two main classes Template.php and Tag.php, with a bunch of extension classes like Img.php and String.php. The program works like this: A Template object creates a Tag objects. Each tag object determines which extension class (...

Which Code Should Go Where in MVC Structure

My problem is in somewhere between model and controller.Everything works perfect for me when I use MVC just for crud (create, read, update, delete).I have separate models for each database table .I access these models from controller , to crud them . For example , in contacts application,I have actions (create, read, update, delete) in c...

design-pattern libraries ready-to-use?

symfony has released some of their components free to use outside the framework. i have used the event dispatcher and dependency injection...they are awesome! i wonder if there are other components/libraries (from other frameworks etc) that in the same way help you manage various design patterns? eg. decorator, facade, singleton, chai...

Why do API's (like Facebook, last.fm etc) generate session keys for logged in users?

Hi All, I am building an RESTful API for an application I am working on and client coders need to be able to submit data to the API on behalf of a user. All the popular API's I've used require me to send the generated session token (created when a user is logged in) for the user with a request to post information on the users behalf. M...

Passing data structures to different threads

I have an application that will be spawning multiple threads. However, I feel there might be an issue with threads accessing data that they shouldn't be. I'm relatively new to threading so bare with me. Here is the structure of the threaded application (sorry for the crudeness): MainThread / ...

[Delphi] How would you refactor this code?

This hypothetical example illustrates several problems I can't seem to get past, even though I keep trying!! ... Suppose the original code is a long event handler, coded in the UI, triggered when a user clicks a cell in a grid. Expressed as pseudocode it's: if Condition1=true then begin //loop through every cell in row, //if aCell/...

With MVVM, does each UI window have its own ViewModel?

When I'm designing multiple views under the MVVM pattern, does each view get its own ViewModel or do they all share the same one? I understand that this is ultimately a flexible decision, but what is the best practice? My gut tells me to have a ViewModel for each view (i.e. each separate UI window). All of the blog examples of MVVM sh...

How to program a connection pool?

Is there a known algorithm for implementing a connection pool? If not what are the known algorithms and what are their trade-offs? What design patterns are common when designing and programming a connection pool? Are there any code examples implement a connection pool using boost.asio? Is it a good idea to use a connection pool for persi...

How to state pattern with asp.net mvc?

Hi One question but I'm looking for two solutions: static dynamic Static means I know all states. Dynamic means I don't know states because end user can define it. Static How to create and organize views, viewmodels and actions? I know that state pattern is well suited for that scenario but how to pass data from view models and put ...

Replace conditional with polymorphism refactoring or similar?

I have tried to ask a variant of this question before. I got some helpful answers, but still nothing that felt quite right to me. It seems to me this shouldn't really be that hard a nut to crack, but I'm not able to find an elegant simple solution. (Here's my previous post, but please try to look at the problem stated here as procedural ...

View artifacts leaking into the model of MVC

In an ASP.NET MVC application (which has very little chance of having its view technology ported to something non-HTML, but whose functional requirements evolve weekly,) how much HTML should ideally be allowed to be directly represented in the Model? I might come across as a design bigot for this, but I regard it as bad practice to allo...

Writing Great Software

Hi, I'm currently reading Head First's Object Oriented Analysis and Design. The book states that to write great software (i.e. software that is well-designed, well-coded, easy to maintain, reuse, and extend) you need to do three things: Firstly, make sure the software does everything the customer wants it to do Once step 1 is complete...

how to make objects globally accessible?

i have this code: class IC_Core { /** * Database * @var IC_Database */ public static $db = NULL; /** * Core * @var IC_Core */ protected static $_instance = NULL; private function __construct() { } public static function getInstance() { if ( ! is_object(self::$_instan...

c++ Design pattern for CoW, inherited classes, and variable shared data?

I've designed a copy-on-write base class. The class holds the default set of data needed by all children in a shared data model/CoW model. The derived classes also have data that only pertains to them, but should be CoW between other instances of that derived class. I'm looking for a clean way to implement this. If I had a base class F...

how to handle exceptions/errors in php?

when using 3rd part libraries they tend to throw exceptions to the browser and hence kill the script. eg. if im using doctrine and insert a duplicate record to the database it will throw an exception. i wonder, what is best practice for handling these exceptions. should i always do a try...catch? but doesn't that mean that i will hav...

design patterns in java

Hello crew I want to learn core java design patterns. Could any one of you suggest good pdf where I could know about the design patters in java with simple examples. Thanks in advance :-) ...

A self-creator: What pattern is this? php

I have several classes that are basically interfaces to database rows. Since the class assumes that a row already exists ( __construct expects a field value ), there is a public static function that allows creation of the row and returns an instance of the class. Here's a pseudo-code ( so there are mistakes and missing improvements in ...

Approaching Java from a Ruby perspective

There are plenty of resources available to a Java developer for getting a jump-start into Ruby/Rails development. The reverse doesn't appear to be true. What resources would you suggest for getting up-to-date on the current state of java technologies? How about learning how to approach DRY (don't repeat yourself) without the use of meta...

Which is the better C# class design for dealing with read+write versus readonly

I'm contemplating two different class designs for handling a situation where some repositories are read-only while others are read-write. (I don't foresee any need for a write-only repository.) Class Design 1 -- provide all functionality in a base class, then expose applicable functionality publicly in sub classes public abstract cla...