Easier Configuration Admin

We are likely to introduce a new service that makes Configuration Admin significantly easier to use. How? By using the Java type machine. Though properties are nice and flexible, they tend to cause cluttered code because of the required checks and conversions. The new model therefore defines configuration types with interfaces. For example, this is how a simple configuration type for a web service would look like:

package com.acme.webconf;
public interface WebConf {
 int port();
 String host();
}

The PID is defined by the interface name, in this example it is com.acme.webconf.WebConf. This "record" has a port (an integer) and a host name (a String). A bundle that wants to receive this information, only has to register a Configurable<WebConf> service. For example:

 @Component
public Webserver implements Configurable<WebConf> {
 public void setup(WebConf conf ) {
   web( conf.port(), conf.host() );
 }
 public void deleted(WebConf conf) {
   stop();
 }
}

No more type error prone type conversions, no more spelling errors in property names or PIDs! And you're not restricted to a single PID, you can extend the interfaces with other interfaces and each extended interface name will automatically be used as PID, merging all underlying configuration records. Annotations in this specification will also make data validation easier.

It is also possible to use factories. In that case, register a ConfigurableFactory, which looks like:

 public interface ConfigurableFactory<WebConf> {
  Configurable<WebConf> newInstance();
  void noConfigurations();
}

This specification will make Configuration Admin significantly easier to use.

Peter Kriens

P.S. Did you already register for the community event?
P.S. And did you look at the Masterclass On OSGi (with certificate) in Girona?