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Lets focus on business value
The presentation by Einar Ingebrigtsen focuses on maximizing business value through Domain Driven Design (DDD), concrete patterns like CQRS and MVVM, and the Bifrost framework that supports these methodologies. It discusses challenges in aligning technical implementations with business needs and emphasizes the importance of agile practices, creative collaboration, and iterative development. The framework aims to simplify application development while ensuring that developers understand and deliver the core business objectives.
Lets focus on business value
- 2. Lets focus onbusiness value Power point template by Colin Eberhardt
- 3. Agenda How to focuson business value Domain Driven Design Concrete patterns; CQRS, MVVM Bifrost – an open-source framework to cover it all
- 4. Who am I Einar Ingebrigtsen @einari einar@dolittle.com http_//www.dolittle.com http://blog.dolittle.com http://www.ingebrigtsen.info
- 5. Statistics Software projects 2009: - 32%successful - 24% failed - 44% challenged 2004: - Cancelled projects cost $55 Billion Annually http://www.projectsmart.co.uk/docs/chaos-report.pdf
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- 7. What are wegetting paid to do? Use the most fancy technology out there C# 5.0, Roslyn, F#, TPL, ASP.net MVC 3, SignalR, RavenDB Join the alpha geek crew and use all the latest buzz words and create an architecture around that showcase our technical skills?
- 8. What is businessvalue? The short answer Helping the business achieve its objectives Faster Simpler Cheaper Better More
- 9. Why is thishard to do? Developers don’t understand what the business needs The Business doesn’t understand what the business needs
- 10. Why is thishard to do? Even if we do understand what they want, we can’t build it because of ... Race Eager conditions Transactions Logging Serialization Performance loading Lazy Caching Mapping Auditing Concurrency Staleness loading
- 11. Why is thishard to do? If somehow we’ve managed to get our infrastructure in place and give the business what it needs, it’s TOO LATE! Legal New Market Changes Priorities Changes New New Acquisitions Requirements Competitor
- 12. Be agile! Not justin terms of process (Scrum, Kanban, XP) We need to be able to change decisions priorities CODE!!
- 13. Understand who youruser is
- 14. Feedback loop Talk tousers regularly Test TDD / BDD Executable Specifications Testers
- 15. Please fail! Fail regularlyand fail fast Be Agile and really iterate Be honest!
- 16. Domain Driven Design Focuson the core domain Creative collaboration between domain experts and software practitioners Create a common language and common understanding of the domain
- 17. Domain Driven Design Buildingblocks Aggregate Roots Value Objects Services Repositories Entities … and more…
- 18. Bounded Contexts Different representationsin different contexts
- 19. Bounded Contexts -Shopping
- 20. Bounded Contexts –Shift Management Employee Plays a central role – identified by Social Security Number Substitute It refers to the Employee by concept, but we do not need its address – only its availability and possibly its name for display purposes
- 21. Decoupling Application Level Makemany applications Unit Level Interchangeable components New Code Velocity
- 22. The opposite ofdecoupling DRY – Don’t Repeat Yourself Use of concrete implementations
- 23. Single Responsibility Principle Typesrepresent one thing Methods do only one thing Be fine grained and clear Easier to name
- 24. CQRS Client Command Queries Domain Event Handlers Publish Persist Update Domain Persistence Read Model
- 25. Command Expresses what shouldhappen Should express intent AddItem- / AddAccessory- ToCart - maps to AddProduct() on the AggregateRoot
- 26. EventSource The source ofevents The place that events originate from
- 27. Aggregate Root Holds onlyinternal state, if needed - no public state Exposes behavior as methods
- 28. Event Represents the truthin the system; “... this is what happened...” Simple DTO with primitive properties only!
- 29. MVVM Model Get from server View Observes Observable ViewModel
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- 31. Bifrost Full end toend framework for line-of- business application development Promotes good practices such as CQRS, MVVM through high focus on DDD You don’t need the entire thing, but will get benefits for every component you add
- 32. Bifrost Our motivation Aplatform for us to build LOB applications on Make us focus on delivering business value Easy to use, hard to use wrong “It just works!”
- 33. Bifrost Client focus JavaScript ASP.net Single Page Applications Web in general Silverlight WinRT (Experimental)
- 34. Bifrost Backend CQRS Cloudscale Realtime applications Clients persistently connected to the server
- 35. Bifrost - Architecture Client Result that affect Queries and Invoke Behavior Results / Read Models Meta Data Server Queries Domain Read Models Meta Data
- 36. CQRS – BifrostStyle Client Command Command Coordinator Command Handler(s) Aggregate Root Read Model Event Subscriber(s) Events EventStore
- 38. User story Persona: Hannah Works with human resources, she is responsible for hiring of permanent employees but also for finding substitutes when people are on sick leaves As Hannah I need to be able to quickly register any employees coming in before we got all the details about the person
- 39. User story Requirements FirstName - Required Last Name - Required Social Security Number – Required This is what identifies a person uniquely
- 40. Where are we?? Client Model View ViewModel Command Command Handler(s) Aggregate Root Read Model Event Subscriber(s) Events EventStore
- 41. Bifrost – Whatdid we solve? Decoupling Commands representing the behavior Events are the contract Read and behavior are two different things Working in parallel Making it easier to apply agile principles
- 42. Bifrost - Roadmap Realtimeapplications Clients persistently connected to the server Refine client model Formalizations Bounded Context, Modules … Simplifications Scale out options Redis, Azure ++
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- 45. Summary Domain Driven Design Willhelp you establish a language and understand what you’re creating CQRS Lets you establish a set of good patterns and practices, mind opener Bifrost One incarnation – but not look at it as a CQRS implementation, it is so much more Please rate the talk at http://tinyurl.com/BusinessValue2 http://blog.dolittle.com http://bifrost.dolittle.com
- 46. Thanks for your attention
Editor's Notes
- #16 Bring up Saga, EventStore, View->Query->ReadHonesty is really omportant – people tend to cover up failures!
- #22 Fewer regression bugsMore stabile softwareEasier to estimate and be on timeLess complexityWriting mostly new code at this point – true velocity!
- #23 DRY : Inheritance for instance – to save propertiesPut in place abstractions for your application needs – not rewrite things!
- #24 The S in SOLID