Hi,
While doing some work on a project where I wanted to create a Map of
elements derived from a Jini configuration I came to the usual
crashing halt because the current Jini configuration approach provides
Java-like syntax, but does not provide any 'real' semantics.
So as a way to get what I wanted done (inspired by what Van Simmons
had done with the Compute Server project), I came up with an approach
to use Groovy classes that can be used as a source with the Jini
configuration approach.
The Jini configuration approach defines an interface for obtaining
objects needed to configure applications, such as Exporter or
ProxyPreparer instances, or other application-specific objects, from
configuration files, databases, or other sources. Configuration
entries are identified by a component and a name.
For example, using the following Groovy class:
@Component('french.fry.bean')
class BeanConfig {
Map getServiceMap() {
Map serviceMap = [ 'foo' : new
org.rioproject.core.ServiceElement()]
return serviceMap
}
}
One could obtain the serviceMap property using the
Configuration.getEntry() method as follows:
Map<String, ServiceElement> serviceMap =
(Map<String,
ServiceElement>)config.getEntry("french.fry.bean",
"serviceMap",
Map.class);
Although this example is trivial, I think you can see the advantage of
using Groovy (POGOs) instead of the static configuration file
approach. All entries you look for will be properties in the Groovy
class. They can be constructed using logic, closures, whatever, and
return the value for the entry accordingly. We also have the advantage
of creating hierarchies of configuration, where POGO configs extend
base configuration classses, provided a much nicer 'overrides'
capability then the approach currently offered with the existing
configuration approach. IMO, this is much more powerful than what we
have now, and also easier to understand.
We have converted all the configuration files in Rio over to POGOs,
the appropriate ConfigurationProvider wiring has been provided, and we
really like it.
I wanted to post this to see if there was any interest on adding this
sort of a capability to River, and to solicit any comments.
Regards
Dennis
