Working on macosx, I often find that things are easier than I thought – just drop something where it makes sense, or do what you would naturally do, and things work as expected. Often, at least.
I had the same experience today playing with OSGi services – one of my services needs to be informed of all configuration changes. OSGi provides a ConfigurationListener interface for that, but how are those registered with the framework?
That’s actually much easier than I thought at first – here’s the complete source code:
import org.osgi.service.cm.ConfigurationEvent;
import org.osgi.service.cm.ConfigurationListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* @scr.component
* immediate="true"
* metatype="no"
* @scr.service
*/
public class DebuggingConfigurationListener implements ConfigurationListener {
private final Logger log = LoggerFactory.getLogger(getClass());
public void configurationEvent(ConfigurationEvent e) {
log.info("Got ConfigurationEvent, pid={}, type={}", e.getPid(), e.getType());
}
}
Not bad hey? The scr.service annotation causes the class to be registered as a ConfigurationListener service, and the framework uses a whiteboard pattern to send configuration events to all such services.
Note to self: make things easier than what people expect.
