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Into the domain
The document outlines key concepts of Domain-Driven Design (DDD), a methodology for developing software that aligns closely with business requirements, focusing on core domains and their identification. It details various components such as models, bounded contexts, aggregates, domain events, and the separation of command and query responsibilities (CQRS). Additionally, it introduces best practices for implementing domain-specific languages (DSL) and emphasizes the use of a ubiquitous language for improved communication in software projects.
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Into the domain
- 1. Into the Domain MayankBairagi Software Consultant Knoldus Software
- 2. Agenda (Part 1) ➢ DomainDriven Design : An Overview ➢ Domain ➢ Model ➢ Bounded Context ➢ Context Map ➢ Relationship Patterns ➢ Domain Objects ➢ Aggregates ➢ Repository ➢ Domain event ➢ CQRS
- 3. Agenda (Part 2) ➢ DomainSpecific Language ➢ DSL : Introduction ➢ Anatomy ➢ Composing DSL ➢ Why Scala for DSL ➢ DSL Design in Scala ➢ Best Practice
- 4. WHAT IS DOMAIN? Domain is a sphere of knowledge, influence and activity - wikipedia
- 5. WHAT IS DOMAIN? Domain is a sphere of knowledge, influence and activity - wikipedia Domain Driven Design is a methodology for evolving software that closely matches our business requirement.
- 6. WHAT IS DOMAIN? Domain is a sphere of knowledge, influence and activity - wikipedia Domain Driven Design is a methodology for evolving software that closely matches our business requirement. Domain-driven design (DDD) is an approach to developing software for complex needs by deeply connecting the implementation to an evolving model of the core business concepts.
- 7. How to Identifycore domain? Ask questions
- 8. How to Identifycore domain? Ask questions like ➢ What keeps you awake at night
- 9. How to Identifycore domain? Ask questions like ➢ What keeps you awake at night. ➢ What makes your system worth writing.
- 10. How to Identifycore domain? Ask questions like ➢ What keeps you awake at night. ➢ What makes your system worth writing. ➢ Why not buy it off the self.
- 11. How to Identifycore domain? Ask questions like ➢ What keeps you awake at night. ➢ What makes your system worth writing. ➢ Why not buy it off the self. ➢ Why not outsource it.
- 12. How to Identifycore domain? Ask questions like ➢ What keeps you awake at night. ➢ What makes your system worth writing. ➢ Why not buy it off the self. ➢ Why not outsource it.
- 13.
- 14. What is Model? Don't think of the model as code.
- 15. What is Model? Don't think of the model as code. Models are abstract set of tools used to solve domain problem.
- 16. What is Model? Don't think of the model as code. Models are abstract set of tools used to solve problem within a domain. Don't try to model reality.
- 17. Models to solveproblem related to temperature
- 18. This is notour world
- 19. Everything simple isfalse Everything which is complex is unusable - Paul Valery
- 20. Ubiquitous Language In orderto search freelancer or project, we will consider inflectional and thesaurus feature of elasticsearch to make the search more relevant. Additionally we will also exclude the stop words from the search to make it more accurate.
- 21. Ubiquitous Language In orderto search freelancer or project, we will consider inflectional and thesaurus feature of elasticsearch to make the search more relevant. Additionally we will also exclude the stop words from the search to make it more accurate.
- 22. Ubiquitous Language In thesearch functionality we will consider all the synonyms of the search phrase so that it does not exclude relevant results. Moreover we will not differentiate any search word by its number (singular or plural), tense, participle etc so that the result becomes more accurate. Additionally as expected in any search, we will ignore all the noise words that do not have any value in the search. Such noise words could be “am”, “but”, “where”, “about” etc.
- 23. Model(s) may represent ➢your core domain.
- 24. Model(s) may represent ➢ yourcore domain. ➢ ➢ a supporting domain
- 25. Model(s) may represent ➢ yourcore domain. ➢ a supporting domain ➢ a generic subdomain.
- 26. Model(s) may represent ➢ yourcore domain. Focus ➢ a supporting domain Consider outsource ➢ a generic subdomain. Consider off the shelf
- 27.
- 28. Bounded Context A domaincan have multiple model , each model can be represented by its bounded context. Delineate applicability of particular module. Explore model in isolation. Own code and persistence mechanism.
- 31. Context Map Draw acontext map of all the bounded context. Map what actually exists , not what you wish exsited.
- 32. Domain Object Entity ➢ Musthave an identity ➢ Must have a life cycle ➢ Most likely Mutable ➢ May be composed of other entities and value objects. Value object ➢ No Identity ➢ Defined by its encapsulated attributes ➢ Treat value objects as immutable. ➢ Delegate business logic to value object.
- 33. Aggregates ➢ Group of relatedentities and value objects ➢ Useful when defining transaction, distribution and persistence. ➢ If two things need to be consistent together Aggregate together ➢ Else They belongs to separate aggregates. ➢ Within a bounded context there may have multiple aggregates.
- 34. Aggregate root ➢ Designate oneentity as aggregate root. ➢ Allow external reference to only the aggregate root. ➢ Persist aggregate root along with its object graph.
- 38. Services A place foroperations that aren't naturally part of a domain object. Services should be treated as immutable. Operations on services are stateless.
- 39. What is DomainEvent ?
- 40. What is DomainEvent ? Something important that happens within the domain that may lead to a stat change is domain object.
- 41. What is DomainEvent ? Something important that happens within the domain that may lead to a stat change is domain object. A domain event can lead to another domain event. eg. 6 balls can trigger an over.
- 42. What is DomainEvent ? Something important that happens within the domain that may lead to a stat change is domain object. A domain event can lead to another domain event. eg. 6 balls can trigger an over. Domain events are immutable.
- 43. What is DomainEvent ? Something important that happens within the domain that may lead to a stat change is domain object. A domain event can lead to another domain event. eg. 6 balls can trigger an over. Domain events are immutable.
- 44. Event Log Domain eventshould be logged into event log. Current state can be computed by reading the event log. If necessary for performance , current state can be cached. Can also serve as an audit log.
- 45. Command Query ResponsibilitySegregation (CQRS) Separate Read/Write model. Define one model for writing data (command) Define another model for reading data (query) Both model operate on same aggregate.
- 48. References ➢ Domain Driven Design: Tackling complexity in the heart of software (By Eric Evans). ➢ http://martinfowler.com/tags/domain%20driven%20design.html ➢ http://dddcommunity.org/ ➢ https://www.youtube.com/watch?v=RNUn2R7TptM ➢ http://www.slideshare.net/thinkddd
- 49.