Patterns, Principles, and Practices of Domain-Driven Design

14 Introducing the Domain Modeling Building Blocks

WHAT’S IN THIS CHAPTER?

• The role of tactical patterns in creating an effective object-oriented domain model
• Introducing value objects, entities, domain services, and modules to model your domain and behaviors
• An overview of the lifecycle patterns: aggregate, factory, and repository
• The emerging patterns of event sourcing and domain events

Wrox.com Code Downloads for this Chapter

The wrox.com code downloads for this chapter are found at www.wrox.com/go/domaindrivendesign on the Download Code tab. The code is in the Chapter 14 download and individually named according to the names throughout the chapter.

Mapping the implementation model back to the analysis model and ensuring they are bound to one another is hard. To guide developers and clarify designs, Evans has built upon the domain model pattern that was first catalogued in Martin Fowler’s book Patterns of Enterprise Application Architecture. He introduces a pattern language containing a number of building block patterns to enable the creation of effective domain models. The patterns, built around best-practice, object-oriented techniques, are sometimes referred to as the tactical patterns of Domain-Driven Design (DDD). Many of the patterns themselves are not new, but Evans was the first to group them in this manner as an aid for developers to create effective domain models. This chapter gives a high-level introduction to the tactical building block patterns of Domain-Driven ...