Re: Application Scoped Object in Web Service

"Mike Schilling" <>
Thu, 18 Oct 2007 22:34:12 -0700
Matt wrote:


I'm an experienced C# dev working on a new project in Java (haven't
touched it since college) and was wondering if I could get some input
on my design. I have a search engine object that will take a non-
trivial amount of time to instantiate and that I need to be exposed
via a web service - it will be a singleton, so that every web service
request will be serviced by it rather than having the overhead of
instantiating a new search engine object with each call.

In C#, I would typically create a Windows service backend that would
host the singleton object and then hook the web service up via .NET
remoting over a TCP binary channel. This has worked great in the past,
but being new to Java I was wondering if there is a better solution to
my problem available in this camp. In Java, I am currently building a
backend service/daemon that will host the singleton and expose it to
the web service via RMI... basically the same pattern with different

Perhaps I'm missing something, but why not co-locate the seatrch engine with
the web service? Create it in Servlet.init() and dispose of it in
Servlet.destroy(); (As far as I know, there's no equivalent of
Servlet.init() in .NET; it allows you to perform initiialization when the
container starts up, as opposed to when the first request is received.)

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