Implementing Domain-Driven Design

Create a Root Entity with Unique Identity

Model one Entity as the Aggregate Root. Examples of Root Entities in the preceding modeling efforts are Product, BacklogItem, Release, and Sprint. Depending on the decision made to split Task from BacklogItem, Task may also be a Root.

The refined Product model finally led to the declaration of the following Root Entity:

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public class Product extends ConcurrencySafeEntity  {     private Set<ProductBacklogItem> backlogItems;     private String description;     private String name;     private ProductDiscussion productDiscussion;     private ProductId productId;     private TenantId tenantId;     ... }

Class ConcurrencySafeEntity is a Layer Supertype [Fowler, P of EAA] used ...