Re: Object pooling
On 21-09-2010 12:58, Robert Klemme wrote:
On 09/21/2010 04:20 AM, Arne Vajh?j wrote:
On 20-09-2010 05:09, Robert Klemme wrote:
On 19 Sep., 23:24, Arne Vajh?j<a...@vajhoej.dk> wrote:
On 19-09-2010 14:13, Tom Anderson wrote:
On Sun, 19 Sep 2010, Robert Klemme wrote:
On 19.09.2010 15:49, Tom Anderson wrote:
I have some heavyweight objects that i would like to try pooling.
To be specific, they're JAX-WS (actually JBossWS) Service (and/or
port) objects. My observations so far are that they take hundreds of
milliseconds to make (if you count instantiation of the service,
instantiation of the port, and extra time taken the first time a
method on the port is called, it seems to be 200-800 ms, depending),
and that the spec doesn't guarantee that they're threadsafe (and as
it happens, i believe that in the JBossWS implementation, neither
the
service nor the port is threadsafe).
Since you are using web services which is a pretty much standard way
of accessing business logic I would expect some prepackaged solutions
to be available.
So would i. I haven't come across any, though.
Axis allows you to define the scope of the service to request,
session or application.
The last will reuse. But it does require the service methods
to be individually thread safe. If that does not work for
you, then you need to look for another solution.
That means you either create a bottleneck or have to do the pooling
internally.
No.
If the methods are thread safe you can make parallel calls
on the same object.
They might still block internally. Either you have a pool internally
which needs some level of synchronization for handing out objects and
taking them back. Or you reuse the same instance which likely has some
state that is not thread sharable (a socket comes to mind). The whole
point of this thread was to pool what amounts to WS service objects
which, according to OP, are not guaranteed to be thread safe. Reusing a
single instance does not scale in this case.
As I wrote "it does require the service methods to be individually
thread safe" and that was intended to mean natural not by internal
blocking.
But given the context then that scenario may indeed be rather unlikely.
Arne
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