Re: Distributed versus local processing
Alaric B. Snell wrote, > On Thursday 31 October 2002 16:32, Paul Prescod wrote: > > Alaric B. Snell wrote, > > > Remote o = Naming.lookup (<registry name>); > > > Method m = o.getClass ().getMethod (<method>,new Object); > > > Object result = m.invoke (o, new Object); > > > > > > System.out.println (result.toString ()); > > > > This makes no logical sense. In order to get the data for a stock > > quote I have to download an appropriate class, find a static > > method, invoke a method coerce the result to string and return it? > > Not done much Java? Ok. What it says is: > > 1) Get a "connection" to the object given the name. Call the result'o' > 2) Find the zero-param method with the given name on that object > 3) Call the method (giving it an empty list of arguments) > 4) Ask the result to display itself I think Paul is probably boggling at the hoops you're jumping through merely to get a string result when you could just as easily have gotten the string directly from the remote service via a much less heavyweight protocol. There are times and places for extruding remote behaviour into a local execution context, but your toy example hardly gives a compelling example of one. > > > That tool can be compiled up and then used to call any zero > > > argument getter method anywhere. If you want to get into ones > > > with arguments then there's a UI issue of setting up arbitrary > > > Java objects for parameters, but it's still doable. You should > > > really call result.toString () in a sandbox, too, since it'd be > > > arbitrary code, but I'm leaving that out for the sake of ease. > > > > You think people should trust the Java sandbox with the execution > > of their most crucial business processes? I can't resist the temptation to plug the forthcoming Java Application Isolation API which (modulo flawed implementations) will make the local execution of untrusted remote code in the way Alaric's suggesting a much less risky proposition than it is now, http://www.jcp.org/jsr/detail/121.jsp It's in community review at the moment, and should be in public review in a couple of weeks. Hopefully you'll see it in the next rev of J2SE and a subset in J2ME. Cheers, Miles
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