Services can be "activated" and "passivated". Applications can be notified of this occurring
by Polygeneâ„¢ runtime by assembling them with an Activator
.
Activators methods are called around "activation" and "passivation": beforeActivation
,
afterActivation
, beforeActivation
, afterPassivation
. The
ActivatorAdapter
class help you keeping your code short when you only need one or two hooks.
To showcase how this works, we refactor the code to create a number of copies of the books, to be lend out
upon call to the borrowBook
method, which will return null if no copy is available. The book
copies are created in the activate
method.
Steps to do.
createInitialData
method to Library
.
HashMap<String,ArrayList<Book>>
.
Activator<ServiceReference<Library>>
class extending
ActivatorAdapter
.
afterActivation
method, use the ServiceReference
to get a
handle on the Library
and call its createInitialData
method.
@Activators
annotation to the LibraryService
declaring the new
LibraryActivator
.