Re: Multiple Servers and Shared Editing Contexts
Re: Multiple Servers and Shared Editing Contexts
- Subject: Re: Multiple Servers and Shared Editing Contexts
- From: David Aspinall <email@hidden>
- Date: Tue, 18 Nov 2003 12:06:34 -0500
I had some of difficulty with the JMS kit also. I wanted multiple
messages (data changes, forecast request, and eventually session
events) I ended up rewriting the kit.
My classes ended up as
JMSCoordinator.java
JMSClient.java
+ -- JMSChangeNotificationClient
+ -- + -- JMSChangePublisher
+ -- + -- JMSChangeSubscriber
+ -- JMSForecastClient
+ -- + -- JMSForecastRequester
+ -- + -- JMSForecastProcessor
The forecast request is initiated much like the change notification, in
that it listens for interesting EO changes, then requests the
forecaster tool to recompute the client's plan automatically, which
then updates cached forecast values in the database, which the client
apps pick up as change notification.
For the notification I also altered it to check the current database
context to see if the updated object was even loaded and only re-fault
it if it was already in memory.
I have also been thinking about only passing global ID's around, rather
than snapshots. Although it seems efficient to send the snapshot, I
found large objects could really hit the JMS server. So if I passed
just the ID and made the object into a fault, then it is re-fetched
only if it is still being accessed.
I also had difficulty with the Java Class Loader. The JMS jar's were
loading in one framework, but it was being initialized by a different
class loader than the frameworks. I was constantly getting class not
found errors for things that I knew were loaded. I ended up having to
create a JAR's framework to merge all the 3rd party jars and allow them
to be loaded by the same loader that the application was using.
Oh, and I had more trouble using RMI on windows, so I switched to TCP
for everything.
I submitted some of the early stuff (before I started rewriting) to
wonder, but I didn't notice if they used any of it.
If you are interested I have placed the JMS and change notification
stuff on my .Mac directory (heh, as a jaguar archive).
http://homepage.mac.com/daspinall
David
On 18-Nov-03, at 10:40 AM, Karl wrote:
Did you ever try using one of the notification frameworks? I am
playing with the Wonder JMS-based framework but can't seem to get it
working just yet.
I would like to propagate updates individual rather than having to
reload all of the data. The number of updates is small compared with
the total amount of data.
Karl
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