Domain Driven Design aligns software with business domains through collaboration with domain experts. Event Storming identifies the “events” that are important to a business domain through collaborative exploration with domain experts. Combining these approaches both simplifies building event driven applications and provides an excellent foundation for development. In this presentation we will use Domain Driven Design principles and Event Storming techniques to build an event driven microservices application and an event driven monolithic application.

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Domain Driven Design, Event Storming,
and Event Driven Applications

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Me
Event
Driven
Architecture
with
Quarkus,
Kafka,
and
Kubernetes
Jeremy Davis
Chief Architect
@argntprgrmr
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Event Storming
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Building a System Using

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Event Storming
Deliberate,
Collective
Learning
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▸ https://www.eventstorming.com
▸ https://www.eventstorming.com/book/
▸ https://openpracticelibrary.com/practice/event-storming

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You Need a LOT of Space
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Event Storming
Past-Tense Verbs
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User
View
Aggregate
Command
Business Process
External System
Colors are a convention
and have meaning

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Home Office Events
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Homeoffice Event Storm

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The colors mean something
Coffeeshop Event Storm
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Domain Driven Design
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Building a System Using

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▸ https://www.domainlanguage.com
▸ https://martinfowler.com/bliki/DomainDrivenDesign.html
Domain Driven Design
Tackling
Complexity
in
the
Heart
of
Software
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Key Concepts
Important Things
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We aren’t going to cover
all of this stuff

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Bounded Contexts
Bounded Contexts Get Lots of Love in the Microservices World
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Also useful for
microservices within a
single system

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Bounded Contexts
Bounded Contexts Get Lots of Love in the Microservices World
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Also useful for
microservices within a
single system

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Ubiquitous Language
This Is Really, Really Important
Enables Collaboration
● Agreed upon by
domain experts and
dev team
● Constantly revisited
and kept current
● Starts with the
Domain Model
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More Concepts
Application Architecture
Let’s look at some code
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Aggregates
Aggrates
Let’s look at some code
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Value Objects
Aggrates
Let’s look at some code
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Repositories
Data Access
Let’s look at some code
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Services
Orchestration
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*Result
Credit to Chris Richardson
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linkedin.com/company/red-hat
youtube.com/user/RedHatVideos
facebook.com/redhatinc
twitter.com/RedHat
Red Hat is the world’s leading provider of enterprise
open source software solutions. Award-winning
support, training, and consulting services make
Red Hat a trusted adviser to the Fortune 500.
Thank you
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GitHub Project
https://github.com/quarkuscoffeeshop
Documentation
https://quarkuscoffeeshop.github.io/
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Resources

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Event Storming
Alberto Brandolini on Youtube
DDD
Eric Evans on Youtube
More Eric Evans on Youtube
DDD on InfoQ
Hexagonal Architecture
Java Design Patterns Site
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Resources

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https://github.com/quarkuscoffeeshop
Commerzbank
Jeremy Davis
Chief Architect
@argntprgrmr
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