Creating a custom UserDetailsService object

While we can link our domain model (CalendarUser) with Spring Security’s domain model (UserDetails), we have to maintain multiple representations of the user. To resolve this dual maintenance, we can implement a custom UserDetailsService object to translate our existing CalendarUser domain model into an implementation of Spring Security’s UserDetails interface. By translating our CalendarUser object into UserDetails, Spring Security can make security decisions using our custom domain model. This means that we will no longer need to manage two different representations of a user.

The CalendarUserDetailsService class

Up to this point, we have needed two different representations of users: one for Spring Security to make security decisions, and one for our application to associate our domain objects to. Create a new class named CalendarUserDetailsService that will make Spring Security aware of our CalendarUser object. This...