I don t think logging is the way to go here, at least not any of the types of logging built into Restlet or the Java API. Those are intended for either programmatic debugging-oriented logging or access logging intended to provide statistics on which resources are being used and by whom. But the real problem is that you wouldn t be measuring the real-world experience which your users would have of your service.
If you want to measure the response times that your users will be experiencing, then you really need to have an approach to sampling which lives outside of your application stack, and ideally outside of your datacenter, so as to simulate as closely as possible the real-world conditions under which your users will be using your service.
If you only need to test the results of fairly straightforward GET
and POST
requests, a service like Pingdom would probably suffice. If your service is more complex, then you may need to write your own sampling app/script, which could serve as a proxy from Pingdom, et al, to your actual service. You should host the sampling proxy on a separate server from your actual service. Google s App Engine might be convenient for this.