implementing ddd concepts in php
DESCRIPTION
A brief introduction to the concepts of domain driven design and their application to PHP.TRANSCRIPT
Implementing DDD Concepts in PHP
Steve Rhoades
Panasonic Avionics
http://github.com/steverhoades@steverhoadeshttp://linkedin.com/in/steverhoadeshttp://stephenrhoades.com
Aleksey KhudyakovRoave, LLC
http://github.com/Xerkushttp://roave.com
Special Thanks
Marco Pivetta, Roave LLC http://github.com/ocramius
Overview• Ubiquitous Language• Bounded Context• Value Object• Entity• Repository• Collection• Mapper• Identity Map• Unit of Work• Services
What is Domain Driven Design
Collection of principles and patterns that help developers craft elegant systems
Ubiquitous Language
Allows for precise communication of ideas between stakeholders and developers
Developers should speak the language as well as include the language in the code base
Bounded Context
Keep varying business processes separated
Overlapping of business concerns should communicate through services
Value Object
An object that contains attributes but does not have an identity
Value Objects are Immutable
Don’t forget behaviors!
Entity
An entity is an object in your application that has an identity.
Anemic Entity anti-pattern
Look like Value Objects but have identity
Lack behavior
Repository
A segregated interface that utilizes the ubiquitous language to hide the infrastructure layer
Storage, Memory, Remote Service
Collections
Mapper (Data Mapper)
Used to pull Entity data from persistence
Developers can create custom Data Mappers without affecting the rest of the application
• Unit Test• MongoDB• Redis• MySQL• Oracle• Web Services• File System
Identity Map
Caches Entities in memory to ensure there is only one instance in memory at any given time
Martin FowlerP of EAA
READ THIS!
Services
Utilized when the natural processing on an Entity or a Value Object is no longer valid
Domain Services should not contain state
Application Services and Domain Services are often confused
Application Services orchestrate demands from a given use case or workflow
Application Services “should not” contain business logic will make calls to Domain and Infrastructure services as well as Entities
Helpful to think of an Application Service as a command object
Unit of Work(example of Application Service)
Maintains a list of objects affected by a business transaction and coordinates the writing out of changes and the resolution of concurrency
- Martin Fowler, P of EAA
Further Resources• Domain Driven Design, Eric Evans• Patterns of Enterprise Application Architecture,
Martin Fowler• Applying Domain-Driven Design and Patterns,
Jimmy Nilsson• Implementing Domain Driven Design, Vernon
Vaughn
Please Review
https://joind.in/9594