Monday, July 31, 2006

open source SOA platform released!

We've been busy getting the latest release of FUSE FUSE 1.2 out of the door - the best new feature is perhaps the Eclipse Tooling - check out the tutorials

We have also included single-sign on security and are now using the Liferay portal!!

Monday, May 01, 2006

Filters for JMX over JMS in Lingo

Just going through some code in lingo and realised that I'd only half put in support for specifiying group and server names for the JMS destination used for communicating between the JMX Connector and Connector server - Doh!

By default any MBean Server using the Lingo Connector will be logically grouped and results of operations and attribute values will be averaged - which can be handy for looking at server stats - e.g. average memory usage across a cluster.

As Lingo's JMX over JMS uses wildcards, by using the destinationGroupName and destinationServerName properties, you can restrict the view from the connector.

On the server side - it would be good practice to always specify the group name and server name, then depending on what the client side connector wants to view, specify exact matches or wild cards.

Saturday, April 29, 2006

File Store Persistence for ActiveMQ

I've recently been working on a file based persistent store (called Kaha) for the ActiveMQ messaging project. There were a couple of reasons for doing this:

  • firstly we are about to re-architect the message dispatching for persistent messages, so having something with a simple interface (Collections) would enable some rapid prototyping
  • It's got to be compatible with the Apache licence - ruling out some well known alternatives
  • I wanted to see if I could provide a faster persistent engine than the current ones we use in ActiveMQ.
For messaging systems, the general pattern for persistence is that messages are short lived in the store - being written and deleted extremely quickly. Messages only tend to be read for message consumers that haven't been active for a while (or slow consumers - when messages are read from the store so as not to constrain other consumers).

Persisted messages are generally read in insertion order, but also need to be accessed by their id so they can be deleted (message acknowledgements can be received out of order - e.g. for Queues). So using a mixture of persistent Maps and Lists from the developers view is ideal.

The Kaha persistence adaptor is available in the latest snapshot of ActiveMQ, though we are not going to push this as a new feature until the 4.1 release. But if you're brave enough - give it a try :)