1. Liquid Victor : Media tracking and aggregation [used to assemble this presentation]
2. Prehensile Pony-Tail : A static site generator built in c#
3. TestHelperExtensions : A set of extension methods helpful when building unit tests
4. Conference Scheduler : A conference schedule optimizer
5. IntentBot - A microservices framework for creating conversational bots on top of Bot Framework
6. LiquidNun : Library of abstractions and implementations for loosely-coupled applications
7. Toastmasters Agenda : A c# library and website for generating agenda's for Toastmasters meetings

• We Learn Things
  • Improved Understanding of the Problem
  • Better Naming of Objects and Operations
  • Separation of similar but different concepts
• Not Big Design Up-Front
  • Good Understanding Up-Front

• As the Business Sees It
• Implementation Agnostic
• Not storage-centric

Practices for designing systems from components that are highly cohesive but loosely coupled

A measurement of the strength of the relationships within a component

• Operations
• Data

How closely the data and the operations on that data match within the context of the component

A measurement of the strength of the relationships between components

• Operations
• Data

The greater the coupling between components, the more likely we are to have to change one as a result of a change to the other

A representation of a real-world entity in software

• Meaningful to the business users
• Encapsulates both state and behavior

A singular viewpoint on the facts and circumstances surrounding a Domain Object

• Flight
  • Traveler's perspecive
    • Departure & Arrival Times & Locations
    • Class of Service & Seat
    • Loyalty Miles
  • Gate Agent's perspective
    • Number of passengers
    • Boarding Time
    • Crew Members

A cluster of domain objects that can be treated as a single unit

• Item Added to Inventory
• Flight Scheduled
• Video Uploaded
• User Logged-In

1. Collect Domain Events
2. Refine Domain Events
3. Track Causes (Use-Case Modeling)
4. Aggregation (Sub-System Modeling)

• Access from Behind the Corporate Firewall only

  • Using the Company SSO solution only

• Users Can:

  • Search for Questions and Answers
  • View details of a Question and its Answers
  • Ask a Question
  • Answer an existing Question
  • Comment on existing questions and answers
  • Report an existing Question, Answer or Comment

• Activity can impact reputation

• Access from Behind the Corporate Firewall only

  • Using the Company SSO solution only

• Users Can:

  • Search for Questions and Answers
  • View details of a Question and its Answers
  • Ask a Question
  • Answer an existing Question
  • Comment on existing questions and answers
  • Report an existing Question, Answer or Comment

• Activity can impact reputation

• Notable Events

  • User Logged-in
  • Question Asked
  • Question Answered
  • Answer Upvoted
  • Comment Submitted

• Interesting Issues

  • Can a question be edited?
  • Can a comment be upvoted?
  • What happens with duplicates?
  • What is actually searched for?

• Notable Changes

  • Events roughly ordered
  • Added Question Removed event
  • Added Report Completed event
  • Filled-In Ubiquitous Language document

• Issues Resolved

  • Questions can not be edited -- comment instead
  • No upvotes of comments or questions (perhaps future)
  • Searches are for keywords and phrases

• Notable Flows
  • User log-in
  • Search
  • View Question
  • Ask Question
  • Answer Question
  • Submit Comment
  • Submit Answer
  • Upvote Answer
  • Report Question
  • Remove Question
  • Close Report

• Notable Aggregates
  • User
  • Report (moderation)
  • Search
  • Comment
  • Question

• Size and complexity of the domain
• Number and the assertiveness of participants

• Step 1 = many conversations
• Steps 2-4 = 1 conversation

You'll need to be able to transfer the physical surface to a virtual whiteboard

• The loudest voices should be from the business
• Technical voices should not be authoritative

• It will hopefully be improved on
• It will almost certainly change

• Facilitators - call attention to the UL often
• Use a spreadsheet for sortability

• There is no "right way" to draw these pictures
• Understanding is the important thing

• Block the time up-front
• Start in-person, then go virtual
• Have a facilitator
• Don't Fall in Love with the Model
• Update the Ubiquitous Language often
• Drawing semantics are not critical

• Modeling process from the perspective of the business experts
  1. Collect Events
  2. Refine Events
  3. Track Causes
  4. Aggregation (Sub-System Modeling)
• Powered by Domain Events
  • Triggered by Users, Business Processes and External Systems
  • Supported by Commands and Read Models
• Produces
  • Visual Model of the Domain
  • Ubiquitous Language
  • Shared Understanding

• http://IntroToEventStorming.azurewebsites.net
• Printable Version of these slides
• Eric Evans on Domain Models
• Alberto Brandolini on Event Storming
• Q&A Domain - Sample Event Storming
• Lucid Chart

• Introduction
• Event Storming Overview
• Sample Domain: Q&A
• Step 1 - Collect Domain Events
• Step 2 - Refine Events
• Step 3 - Track Causes
• Step 4 - Aggregate (v)
• Recommendations
• Summary
• Resources