This example shows how to use JPA with an entity. The entity manager is used in the persistence implementation.
It implements a
BookingService similar using a database for the storage, with a JPA entity.
This example uses blueprint and declarative service to deal with JPA entity manager.
The “command” bundle uses the
Bookingentity used in the
BookingService. As a best practice, this bundle should use a common bundle containing the
BookingServiceinterface, and then wrapping
BookingPOJO as a
JpaBookingentity for instance. For convenience and reduce the number of example artifacts, we gather interface and implementation in the same bundle (again, it's bad).
BookingService. It use declarative service to retreive one instance of a
BookingService. If you want to use several service provider, you have to stop the actual service and install the new one.
The build uses Apache Maven. Simply use:
mvn clean install
On a running Karaf instance, register the features repository using:
karaf@root()> feature:repo-add mvn:org.apache.karaf.examples/karaf-jpa-example-features/LATEST/xml
Then, you can install the datasource feature:
karaf@root()> feature:install karaf-jpa-example-datasource
Then, you can install the service command feature (commands booking:xxx will not be available until you have installed a provider):
karaf@root()> feature:install karaf-jpa-example-command
And install the service provider you want to use (for example EclipseLink using declarative service):
karaf@root()> feature:install karaf-jpa-example-provider-ds-eclipselink
Once you have installed the feature, you can see new commands available in the Apache Karaf shell.
booking:add command adds a new booking in the booking service. For instance:
karaf@root()> booking:add Doe AF520
booking:list command lists the current bookings:
karaf@root()> booking:list ID │ Flight │ Customer ────────┼────────┼───────── 1 │ AF520 │ Doe
booking:get command get the booking with id:
karaf@root()> booking:get 1 ID │ Flight │ Customer ────────┼────────┼───────── 1 │ AF520 │ Doe
booking:remove command removes a booking from the booking service:
karaf@root()> booking:remove 1