(Quick Reference)
                scope
Purpose
Changes the scope of a service
Examples
class BookService {
    static scope = "session"
    …
}Description
By default services are "singleton" scoped which means that clients of a service only ever use a single instance (a singleton) of the service. This behaviour can be changed by specifying a 
scope attribute with on the following values:
- prototype- A new service is created every time it is injected into another class
- request- A new service will be created per request
- flash- A new service will be created for the current and next request only
- flow- In web flows the service will exist for the scope of the flow
- conversation- In web flows the service will exist for the scope of the conversation. ie a root flow and its sub flows
- session- A service is created for the scope of a user session
- singleton(default) - Only one instance of the service ever exists
See 
Scoped Services in the user guide for more information.