1. Event Driven Architecture
When we have to use an Event Driven Architecture?
Initially, Current Practices and Future

2. What we will cover here What is the Event Driven Apps?
When is the Event Driven Architecture was started?
What is the Benefit?
When we have to use?
What is the Implementation in the real world?
What is the trend?

3. What is the Event Driven Apps?
What is an Event?
What is in an Event?
What is the Reaction when an Event fires?

4. Ask Wiki!
An event is a notable thing that happens inside or outside your business
The term event is often used interchangeably to refer to both the specification (definition) of the event, and each individual occurrence (instance) of the event
Each event occurrence has an event header and event body as the delivered information

5. How’s an Event being consumed?
It should be Published!
And then Fired!
And someone must Listen!
And he /she will give some Reaction!
Or, just ignore it!...

6. Simply, EDA will be as
Event Listener
Event Action

7. Publishing Events

8. Various Reactions to the Events

9. The Problem on Event Trigger
Triggered by Predictable Events
Triggered by Un Predictable Events
Required Active Listeners

10. Listening Event Activity

11. The Problem on the Action
Synchronous Action
Asynchronous Action

12. When is the Event Driven Architecture was started?
Four years from now, "mere mortals" will begin to adopt an event-driven architecture (EDA) for the sort of complex event processing that has been attempted only by software gurus building operating systems or systems management tools, and sophisticated developers at financial institutions. (Roy Schulte, an analyst at Stamford, Conn.-based Gartner )

13. What is the Benefit? Scalable Reaction based Staged
Staged + Reaction =

14. When we have to use? Samples:
Best used for Asynchronous Flows of Work and Information
When you need a Fast Responsive in front, but Asynchronous process in the background
Fire and Forget handling
Samples:
The Web Server

15. What else? (Quiz) Use these following key words:
Replication
Scheduler
Reporting
Synchronization
Messenger
Then add with word “Engine“

16. What is the Implementation in the real world?
SOA based implementation
Messaging based solution
Automation solution
Workflow solution

17. Sample of Messaging Solution

18. Sample of Workflow

19. Sample of Complex Workflow

20. Existing Sample
NatPOS WindMills using SEDA Implementation

21. What is the trend? Workflow enabled application
From Enterprise Level to Single Instance Application

22. From Enterprise Level: Biztalk

23. To Single Instance: WWF
Sequential Workflow
State Machine Workflow
Rule Driven Activities

24. WWF in brief Sequential Workflow State Machine Workflow
structure
prescribes
processing order
External
events drive
processing
order
Step1
State1
Event
State2
Step2
Event
Prescriptive, formal
Automation scenarios
Flowchart metaphor
Reactive, event-driven
Skip/re-work, exception handling
Graph metaphor
Rules-driven Activities
Rule1
Step1
Rules + data state
drive processing
order
Data
Rule2
Step2
Data-driven
Simple Conditions, complex Policies
Constrained Activity Group

25. Demo

26. Questions & Discussions

27. Thank you
References:
4 Years prediction on SOA implementation - Gartner
Event Driven Architecture – InfoQ article
Microsoft .NET Framework 3.0, 3.5, WWF
NatPOS workflow engine - WindMills