2011-05-22 domain driven design

Domain Driven Design

Ismael Santos

@ifsantosrs

What is

DDD?

What is DDD?

Domain X Software

● Do you know what the software is talking about?

Ubiquitous Language

Ubiquitous Language

● Is a programming language?● Is an human language?● WTF is it??

Ubiquitous Language

Model Driven Design

● Is important to divide the application domain● The application construction must explain

about the domain

Entities

● Everything that needs an identity● Needs to be uniquely referenced● Examples: Order, Product, Route, etc.

Value Objects

● Elements that dont need an identity● Fast life-cicle● Can be constant● Example: Delivery address, Credit card

number, Font type, etc.

Agregates

● Encapsulate Entities and Value Objects from a comnon subject, to give easy acess to useful data

Entity

EntityValue Object

Value Object

Agregate

Factories

● Used to construct some elements when it is complex.

● Used in Agregates and Vaue objects● Encapsulate the contruction process

Services

● Is an operation that is not part of any Entity or Value Object

● Stateless● Follow the Ubiquitous Language

Modules

● Are like chapters from a story● Are about model, not about code

Repositories

● Used to store/retieve Entities and Agregates● Is centralized

Global vision

Ubiquitous Language Model Driven Design

Services

EntitiesValue Objects

Modules

FactoryAgregate Repository

References

● http://domaindrivendesign.org/resources/what_is_ddd

● http://en.wikipedia.org/wiki/Domain-driven_design

● http://www.infoq.com/minibooks/domain-driven-design-quickly

● http://vimeo.com/3545313

● Java Magazine, ed. 87

Feel free to DDD!

Thank you!