1.
Introduction to Domain Driven Design <ul><ul><li>Aqris Software </li></ul></ul><ul><ul><li>Ürgo Ringo </li></ul></ul>

2.
Sample use case – enter activity <ul><ul><li>Basic flow </li></ul></ul><ul><ul><li>User wants to enter new activity. System displays new form where some fields have been filled based on last entered activity. User enters activity and submits form. System validates and adds activity into persistence storage if it's valid. </li></ul></ul><ul><ul><li>Business rules </li></ul></ul><ul><ul><li>- activity description must not be empty </li></ul></ul><ul><ul><li>- activity must start before it ends </li></ul></ul><ul><ul><li>- activity duration must not overlap with existing ones </li></ul></ul><ul><ul><li>- JIRA key must exist in JIRA </li></ul></ul>

3.
“Domain Model” - non-DDD way UML class diagram

4.
Show form - non-DDD way <ul><ul><li>UML sequence diagram </li></ul></ul>

5.
Submit form – non-DDD way UML sequence diagram

6.
Benefits of non-DDD way <ul><li>easy to learn </li></ul><ul><li>simple OR mapping </li></ul><ul><li>easier to avoid performance problems Good for small systems(?) </li></ul>

7.
Problems of non-DDD way <ul><li>procedural implementation </li></ul><ul><li>anemic domain model </li></ul><ul><li>boilerplate service layer </li></ul><ul><li>fat controllers Expensive to develop/maintain </li></ul>

8.
How to improve design <ul><ul><li>Using ideas of DDD and Domain Model </li></ul></ul><ul><ul><li>Domain Driven Design – E. Evans </li></ul></ul><ul><ul><li>Patterns of Enterprise Application Architecture – M. Fowler </li></ul></ul>

9.
What is DDD (1) <ul><li>Entity e.g Activity, Project, User </li></ul><ul><li>ValueObject e.g Duration, Address </li></ul><ul><li>Service e.g JiraService, EmailNotificationService, TransferService </li></ul>

10.
What is DDD (2) <ul><li>Facade e.g EnterActivityFacade, ViewActivitiesReportFacade </li></ul><ul><li>Specification e.g ActivityDurationSpecification, UsernameSpecification </li></ul><ul><li>Repository e.g ActivityRepository, ProjectRepository </li></ul><ul><li>Factory e.g ActivityFactory </li></ul>

11.
Domain Model - DDD way UML class diagram

12.
Show form - DDD way UML sequence diagram

13.
Submit form - DDD way UML sequence diagram