| [[tut-services-step2,Step 2 - Hooking into the Service Activation]] |
| = Step 2 - Hooking into the Service Activation = |
| |
| Services can be "activated" and "passivated". Applications can be notified of this occurring |
| by Qi4j 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: |
| |
| - Add a createInitialData method to Library. |
| - In the implementation, create a couple of books of each title and store each copy in a HashMap<String,ArrayList<Book>>. |
| - Write an Activator<ServiceReference<Library>> class extending ActivatorAdapter. |
| - Override the afterActivation method, use the ServiceReference to get a handle on the Library and call its createInitialData method. |
| - Add the @Activators annotation to the LibraryService declaring the new LibraryActivator. |
