Home - Tulsa TechFest 2011

The CAP Theorem and its Consequences

In 2000, Eric Brewer postulated the CAP Theorem. It defines the behavior of distributed systems. Since then, we have based several architectures on this work.

The CAP Theorem states that any subsystem can have only two of these three attributes:

Consistency
Availability
Partition Tolerance

Consistency is the property that two users see the same state. Availability means that a node gives a meaningful response in a reasonable period of time. Partition Tolerance allows a system to continue operating in the face of repeated message loss.

If you can have only two, which two do you choose? Traditional architectures have chosen consistency over partition tolerance. New architectures are reversing that trend.

We will discuss architectural decisions, such as:

Eventual Consistency
Event Sourcing
Command Query Responsibility Segregation

I will demonstrate ways of coding these architectures, and the benefits and drawbacks of each technique.

Oct 7th

Correspondence: Building Occasionally-Connected Out-of-Browser Silverlight Applications

Silverlight is not just a browser plug-in. It is a platform for delivering rich desktop applications. When used out-of-browser, it has access to isolated storage and the ability to run off-line. Correspondence helps you take advantage of these features.

Correspondence automatically synchronizes your application's local data with other users and other devices. When you design your data model using its DSL, it generates both a local database and a network protocol. Then it gives you an object model to code against that seamlessly bridges local and remote.

I'll walk you through the development of a collaborative application, Thought Cloud. We'll cover the following topics:

The Facutal modeling language
The Community
The view model layer
Publish/subscribe communications
Good Silverlight citizenship
asynchronous behavior
network status
quota elevation

Oct 7th

Data Binding without INotifyPropertyChanged

Data binding in WPF and Silverlight is extremely powerful. However, it can also be painful. The most painful part is knowing when to raise PropertyChanged events.

Update Controls is an open source library that takes that pain out of XAML development. It discovers dependencies within your code, and fires PropertyChanged events on your behalf. It's not simply an INotifyPropertyChanged wrapper. It's completely automatic.

In this talk, I'll show you how to data bind in both WPF and Silverlight without INotifyPropertyChanged. I'll demonstrate patterns, starting with MVVM and MVC, and going beyond to Navigation Model and VM Tuple. These patterns enable a fluid style of rapid feature development not previously possible.

Theory
MVVM review
Stateful vs. Stateless View Models
MVC and MVP
Practice
Contact list example
Navigation model
View Model Tuple