About the book

Written by: K. Scott Allen
Pages: 300
Publisher: Packt Publishing 
ISBN: 1904811213

Introduction

WF allows developers to build workflow enabled applications, and Scott Allen’s book does not disappoint introducing the core concepts of WF and progressively introducing the more complex parts of WF.

The great thing about WF is that if you are creating any application that represents some sort of workflow you will really appreciate this new technology.

Initial thoughts

This book on the face of it looks very manageable, it’s not 1000 pages long, and when you flick through it you don’t see page after page of tables explaining types/methods – documentation is for that.

It is often the case that people read technical books in their spare time, and it’s essential that the book has a consistent structure – ideally we want the book to flow from chapter to chapter seamlessly - Allen’s book does exactly that.

The first half of the book covers the essential need to knows with the second half of the book delving into the more intermediate/advanced features of WF.

One thing to remember with this book is that the title implies that it is of introductory level only, so don’t expect to be an absolute whizz at WF upon completion – do expect however to have a core understanding of what WF is and how to incorporate the technology into your applications.

Getting to grips with Workflow

Perhaps the simplest type of workflow is one that executes the next activity when its preceding activity has been completed – having never used WF before I really appreciated the amount of time Allen dedicated in his book to making sure that the reader grasped the core concepts of this workflow.

Something which I really liked about this book was that rather than spending page after page talking about the API the reader was given some theory then a clear example of applying that knowledge in a working example, and along the way Allen would point out any key types with clear explanations of why they were important.

We are treated to a fully functional example of a workflow in WF very early on in the book, with the workflow replicating a simple bug tracking example.

Although the first application is a very simple one it is actually fairly hard to code up, remember that we are replicating a business process – activities in that process may not be completed for hours, days, weeks, months and so on - WF comes out of the box with the ability to resume its previous state which is an invaluable feature. WF can harness the power of SQL Server 2005 to store the state of a particular workflow, and then resume the workflow at a later stage.

It is clear from the outset that WF is incredibly useful for anything that is loosely (or strictly) based on a process of activities – maybe you also want to create a bug tracking application that can maintain state? What about an ecommerce site that uses WF for payment processing and the like? Maybe an expense application where line managers have to sign off expenses and so on – all of these scenarios would benefit immensely from the use of WF.

It’s worth noting that from the people I speak to on a daily basis (programming pros) everyone mentions either WF or WCF being really great technologies that are going down a treat with all sizes of businesses – and individuals of course!

Base Activity Library

WF comes with many activities ready to use out of the box and Allen dedicates a whole chapter explaining when to use each activity and how to apply them to real world scenarios.

Having gained a decent understanding of WF this chapter really helps to guide you in the right direction, after all this book is an introduction so it’s understandable that the reader may need guidance in this early period of using WF.

State Machines

Towards the end of the book we are introduced to event driven workflows, it’s not totally new to us however as we have already looked at some event driven activities earlier on in the book which helps us grasp this concept quite rapidly.

Allen makes sure to cover helpful topics like state machine tracking and how to effectively inspect our state machines throughout this chapter.

Other key coverage

Allen also dedicates chapters in the book to hosting the workflow runtime, creating custom activities, communication in workflows and finally wraps the book up with a chapter dedicated to rules and conditions.

Summary

I found Allen’s book a joy to read, progressing from chapter to chapter smoothly and I was left feeling more and more comfortable with WF as the book progressed. Upon completion of reading the book I had no negative opinions of any chapters – the book provided everything that a newcomer to WF requires along with some well thought out demo applications.

Strongly recommended to anyone who has never used WF before and wants to see how WF can benefit their applications.

About Granville Barnett

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