From EventStorming to CoDDDing - Javaland 2019

To really understand what our users need so that we can build the right thing, we want to have a first-hand experience of 'real-life stories' before we model and create our software. To quote Alberto Brandolini "it is not the domain expert's knowledge that goes into production, it is the developer's assumption of that knowledge that goes into production". EventStorming is a visual technique that minimizes assumptions by engaging in collaborative deliberate learning across different disciplines. This helps to solve complex business problems in the most effective way.

Although the learning of the domain helps us to understand the domain better, EventStorming can be quite an overwhelming experience. Developers can be left with the question of how to turn a few stickies on a wall into working code.

Join us in this talk in which we show the basic principles of EventStorming. We will cover the different forms of EventStorming and in which situation they best can be applied. And, we will show how you can leverage DDD (Domain-Driven Design) patterns in an EventStorming software modeling session that will ultimately result in coding TDD (Test Driven Development) style!

Transcript

1. From EventStorming
   to CoDDDing
   

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2. 2
   Strategic Technology Consultants -
   Agile Technical Coaches -
   Domain-Driven Design - Continuous
   Delivery - EventStorming - Example
   Mapping
   @kenny_baas
   baasie.com
   @joaoasrosa
   joaorosa.io
   

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4. 4
   @kenny_baas @joaoasrosa
   

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7. 7
   The fundamental horror of this anti-pattern
   is that it's so contrary to the basic idea
   of object-oriented designing;
   which is to combine
   data and process together.
   - Martin Fowler
   @kenny_baas @joaoasrosa
   

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8. 8
   What's worse, many people think that
   anemic objects are real objects,
   and thus completely miss the point of what
   object-oriented design is all about.
   - Martin Fowler
   @kenny_baas @joaoasrosa
   

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9. 9
   @kenny_baas @joaoasrosa
   

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10. 10
    @kenny_baas @joaoasrosa
    

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11. We all know or should know that language is fluid, liquid, subject to the
    whims of the people. Language evolves, as it should. Because language
    changes to accommodate new users, the older users resist and complain.
    http://tednellen.blogspot.com/2013/04/language-is-fluid.html
    

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16. 16
    @kenny_baas @joaoasrosa
    

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17. 17
    Confirmation Bias
    @kenny_baas @joaoasrosa
    

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18. 18
    @kenny_baas @joaoasrosa
    

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19. 19
    It is not the domain experts knowledge
    that goes to production, it is the
    assumption of the developers
    that goes to production
    - Alberto Brandolini
    @kenny_baas @joaoasrosa
    

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20. 20
    @kenny_baas @joaoasrosa
    

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21. 21
    The greatest obstacle to discovery is not ignorance -
    it is the illusion of knowledge.
    - Daniel J. Boorstin
    @kenny_baas @joaoasrosa
    

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22. 22
    @kenny_baas @joaoasrosa
    

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25. 25
    Big Picture
    Process Design
    and Modelling
    Software
    Modelling
    @kenny_baas @joaoasrosa
    

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26. 26
    @kenny_baas @joaoasrosa
    

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27. 27
    @kenny_baas @joaoasrosa
    

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28. 28
    @kenny_baas @joaoasrosa
    

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31. 31
    Source: https://medium.freecodecamp.org/coding-explained-in-25-profound-comics-8847ea03819c
    @kenny_baas @joaoasrosa
    

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32. 32
    Source: https://nl.pinterest.com/pin/550846598149452758/
    @kenny_baas @joaoasrosa
    

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33. 33
    Source:https://www.dw.com/en/maligned-ronaldo-statue-replaced-at-madeira-airport/a-44279114
    @kenny_baas @joaoasrosa
    

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34. 34
    Solution Space
    Our world as we designed it
    Bounded Context
    Software Architecture
    Linked to the business
    Problem Space
    Our world as we perceive it
    (Sub)Domains
    Business Architecture
    Independent of Software
    @kenny_baas @joaoasrosa
    

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35. 35
    @kenny_baas @joaoasrosa
    

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36. 36
    A model is a simplified representation of a thing
    or phenomenon that intentionally emphasizes
    certain aspects while ignoring others.
    Abstraction with a specific use in mind.
    @kenny_baas @joaoasrosa
    

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37. 37
    @kenny_baas @joaoasrosa
    

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38. 38
    @kenny_baas @joaoasrosa
    https://blog.ncrunch.net/post/london-tdd-vs-detroit-tdd.aspx
    

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40. 40
    Source: https://nl.pinterest.com/pin/550846598149452758/
    @kenny_baas @joaoasrosa
    1. Write a coarse-grain test
    a. Outside-in testing
    2. Start with entrypoint of our model
    3. Design-by-Coding
    4. Assess if the models can easily
    evolve to support other features
    

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41. 41
    @kenny_baas @joaoasrosa
    

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42. 42
    1. Protects business invariants
    2. Design them small
    3. Reference other by ID only
    4. Update other using eventual
    consistency
    @kenny_baas @joaoasrosa
    

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43. 43
    @kenny_baas @joaoasrosa
    Source: https://unsplash.com/photos/eYZpTMc7hno
    Domain logic that doesn’t belong to a
    - Entity
    - Value Object
    Significant process or transformation that
    concerns the domain logic
    Isolate in a standalone interface
    declared as a service
    Part of the ubiquitous language
    

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44. 44
    @kenny_baas @joaoasrosa
    

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45. 45
    Source: http://www.mamuz.de/article/from-big-ball-of-mud-to-emergent-design/0Pw682Kxk
    @kenny_baas @joaoasrosa
    

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47. 47
    Source: http://www.mamuz.de/article/from-big-ball-of-mud-to-emergent-design/0Pw682Kxk
    @kenny_baas @joaoasrosa
    1. Visualise
    a. Business information flow
    b. Behaviour of the system
    2. Protect domain logic with tests
    a. Inside-out
    b. Outside-in
    3. Experiment models to fit the
    behaviour
    a. Ubiquitous language will
    emerge
    4. Protect models with Bounded
    Contexts
    

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48. 48
    @kenny_baas @joaoasrosa
    

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49. 49
    Software Development is
    a learning process, working code is a
    side effect.
    - Alberto Brandolini
    @kenny_baas @joaoasrosa
    

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50. 50
    Try at least to find three models,
    even if you think you already found
    the “right model”
    @kenny_baas @joaoasrosa
    

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51. 51
    Serious software development is
    the practice of symmathesy.
    “Sym” = together, “mathesy” = learning.
    - Jessica Kerr
    @kenny_baas @joaoasrosa
    

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52. #CatTax
    

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