Services typically have configuration. Configurations are directly supported in Polygene™. A
ConfigurationComposite
is a subtype of EntityComposite
. That is because
configurations are stored in EntityStores, can be modified in runtime by client code and has
the same semantics as regular entities.
Polygene™ also handles the bootstrapping of configuration for the services. If the ConfigurationComposite is
not found in the configured entity store, then Polygene™ will automatically locate a properties file for each
service instance, read those properties into a ConfigurationComposite instance, save that to the
entity store and provide the values to the service. The properties file must be with the same name as
the service instance with the extension "properties"
in the same package as the service.
For this exercise, create a LibraryConfiguration
that contains "titles", "authors" and "copies".
The first two are a string with a comma separated list, and the "copies" is just an Integer with how many
copies are made of each title.
Steps to do.
LibraryConfiguration
interface that extends ConfigurationComposite
,
and has three Property
instances named "titles"
, "authors"
and
"copies"
, where the first two are of String
type and the last is of
Integer
type.
LibraryActivator
and remove the @Activators
annotation from the
LibraryService
and the corresponding createInitialData
method.
LibraryMixin
remove the member injection of the ValueBuilderFactory
, and
instead inject the ValueBuilderFactory
in the constructor.
LibraryConfiguration
via the constructor. The injection scope is @This
.
LibraryService.properties
and place it in the directory
org/apache/polygene/tutorials/services/step4
in the classpath (for instance, src/main/resources
).
Put something like;
titles=Domain Driven Design, Pragmatic Programmer, Extreme Programming Explained authors=Eric Evans, Andy Hunt, Kent Beck #Number of copies of each book. copies=3in this file.
LibraryConfiguration
in the LibraryMixin
constructor.