In previous chapters, we went through a different level of knowledge crunching and domain analysis. We used EventStorming as our primary tool so as a result of our effort, we got plenty of paper rolls with lots of colorful sticky notes on them. But how can we make some working code from it? That is a good question, and this is precisely what we will start doing when moving along this chapter.

By the end of this chapter, we will have a basis of our domain model implemented in code. We will go through different styles of performing the behavior in domain entities and also will write some tests.

The following topics will be covered:

• Create a project for the domain model
• Add domain objects to the new project
• What are the entities and value objects
• How to ensure that domain model is always in a valid state