design-patterns

Protocol specification in XML

Is there a way to specify a packet-based protocol in XML, so (de)serialization can happen automatically? The context is as follows. I have a device that communicates through a serial port. It sends and receives a byte stream consisting of 'packets'. A packet is a collection of elementary data types and (sometimes) other packets. Some el...

In M-V-VM where does my code go?

So, this is a pretty basic question I hope. I have a web service that I've added through Add Service Reference. It has some methods to get list and get detail of a perticular table in my database. What I'm trying to do is setup a UI as follows: App Load Load service proxy Call the GetList(); method display the results in a ListBox c...

How to properly dispose of an object

Hi Guys, I am experiencing something weird and have a workaround already, but I don't think I understood it well. If I call the Method below numerous times within a class: public void Method() { Foo a = new Foo(); a.Delegate1Handler = ViewSomething(); } If I call Method() multiple times in one instance of the class that it is in....

Doubleton Pattern Implementation

I'm leveraging the Doubleton Pattern from the Doubleton Design Pattern on Code Project in my own code. I think it makes things a lot easier since the Singleton only provides one instance, but I get two with this pattern. I was wondering if it would make sense to have it implement an interface so I can inject it into my domain layer. ...

Optional Member Objects

Okay, so you have a load of methods sprinkled around your system's main class. So you do the right thing and refactor by creating a new class and perform move method(s) into a new class. The new class has a single responsibility and all is right with the world again: class Feature { public: Feature(){}; void doSomething(); ...

design decision between array or object save in database

i code some configuration setting. And need those values to be load, everytime my webapp start. yes, it's somekind autoload setting. But, right now, i have to choose between save it as object or array. is there any different between them when we save them in database ? which one is faster or maintainable or other pro and cons thanks ...

What design pattern to use for one big method calling many private methods

I have a class that has a big method that calls on a lot of private methods. I think I want to extract those private methods into their own classes for one because they contain business logic and I think they should be public so they can be unit tested. Here's a sample of the code: public void handleRow(Object arg0) { if (continu...

Modelling multiple simultaneous states

How can you go about modelling an object that can have multiple simultaneous states? For example, you could have a person that's waiting for a bus. That's one state. But they could also be reading a newspaper while waiting for the bus. Furthermore, they could be thinking about something while reading the newspaper. They could also be sn...

More swing design & actions

Im pretty new to gui programming so i've been reading through every post on this site about swing and design. Whats been answered over and over again is that one should have a multiton class for the actions. Like this: (GUI being some JFrame) Now, this works great for one-way actions, like OpenDialog. But the actions for buttons in Di...

Where does the query language sit within the MVC pattern?

I'd assume that since the query language sits within the controller (typically) that it belongs to that component, but if I play devil's advocate I'd argue that the query language is execute within the domain of the model, and is tightly coupled to that component so it might also be a part of it. Anyone know the answer? Is there a strai...

Best way to handle global state

Hi there, I was wondering if anyone could offer some advice on 'best practices' for using global state in a web application - specifically PHP, although im looking for generic best practices i.e. design patterns etc. At the moment I just use a static class, calling it Configs. I suppose this is similar to using the registry pattern but...

looking for a pattern with a management of items list in an object in asp.net

I've catalogs of a list items, each catolog containing a list product. I would like to display each category in a separate popup. The objective of this solution is to extract the categories and list product associated with the possibility to modify this list of products. objective was to modify the following two properties: product name...

What's the proper approach for writing multi-path "story" flows?

Hi, I wonder if you can help me. I'm writing a game (2d) which allows players to take multiple routes, some of which branch/merge - perhaps even loop. Each section of the game will decide which section is loaded next. I'm calling each section an IStoryElement - And I'm wondering how best to link these elements up in a way that is easi...

Sequencing ajax requests

I find I sometimes need to iterate some collection and make an ajax call for each element. I want each call to return before moving to the next element so that I don't blast the server with requests - which often leads to other issues. And I don't want to set async to false and freeze the browser. Usually this involves setting up some k...

Should I dive into ASP.NET MVC or start with ASP.NET Webforms?

I plan to pick up Silverlight in the future. Possibility of going into Microsoft WPF. Currently learning Objective-C 2.0 w/ Cocoa. I already know Pros and Cons of ASP.NET MVC vs ASP.NET Webforms. What I want to know is what would be more "efficient" for me to learn given the circumstances above? By efficient I mean learning one desig...

Separating data from the UI code with Linq to SQL entities

If it's important to keep data access 'away' from business and presentation layers, what alternatives or approaches can I take so that my LINQ to SQL entities can stay in the data access layer? So far I seem to be simply duplicating the classes produced by sqlmetal, and passing those object around instead simply to keep the two layers a...

Why doesn't DomainContext from WCF RIA Services implement the IDisposable pattern ?

Hi, Just doing some work with RIA services and I see in the MSDN documentation that neither it or any parents up its' hierarchy implement IDisposable. I'm wondering what the design decision was for this...as DomainContext is a stateful resource, wouldn't it be nice to have a Dispose() to release it when done ? Thanks, Scott ...

Is MVVM killing silverlight development?

This is a question I have had rattling around in my head for some time. I had a chat with a guy the other night who told me he would not be using the navigational framework because he could not figure out how it works with MVVM. As much as I tried to explain that patterns should be taken with a pinch of salt he would not listen. My poin...

Is it possible to implement Separated Interface in PHP?

I recently asked a question regarding the resolution of dependencies between Unit of Work and Data Mapper classes: http://stackoverflow.com/questions/3012657/dependency-injection-and-unit-of-work-pattern - (which was answered by Gabor de Mooij - thx) In PoEAA, Martin Fowler suggests using Separated Interface to manage these dependencie...

OO Design / Patterns - Fat Model Vs Transaction Script?

Ok, 'Fat' Model and Transaction Script both solve design problems associated with where to keep business logic. I've done some research and popular thought says having all business logic encapsulated within the model is the way to go (mainly since Transaction Script can become really complex and often results in code duplication). Howeve...