Book Image

Reactive Programming for .NET Developers

Book Image

Reactive Programming for .NET Developers

Overview of this book

Reactive programming is an innovative programming paradigm focused on time-based problem solving. It makes your programs better-performing, easier to scale, and more reliable. Want to create fast-running applications to handle complex logics and huge datasets for financial and big-data challenges? Then you have picked up the right book! Starting with the principles of reactive programming and unveiling the power of the pull-programming world, this book is your one-stop solution to get a deep practical understanding of reactive programming techniques. You will gradually learn all about reactive extensions, programming, testing, and debugging observable sequence, and integrating events from CLR data-at-rest or events. Finally, you will dive into advanced techniques such as manipulating time in data-flow, customizing operators and providers, and exploring functional reactive programming. By the end of the book, you'll know how to apply reactive programming to solve complex problems and build efficient programs with reactive user interfaces.
Table of Contents (15 chapters)
Reactive Programming for .NET Developers
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Preface

Inspecting sequences


After tracing what flows within a sequence, the second most useful diagnostic feature is to verify the sequence content against a predicted content or a static content (usually for testing purposes with mocking objects) simply because we need to check the message homogeneity. Luckily, there are different operators that help us achieve this.

Contains

This is maybe the easiest case to deal with when we need to check if/when a sequence contains a given value.

In reactive, we always deal with sequences; this is true also when we want to aspect a Boolean value, as in this case, if we were programming in a nonreactive way. The Contains extension method produces a new sequence that will fire a single message with a value informing us if we found what we're searching for immediately after the sourcing sequence is complete. This is easily visible by instrumenting Rx materializing our Contains sequence. Here's an example:

var r = new Random(DateTime.Now.GetHashCode());
 
//an infinite...