2008/5/9 Stefano Bagnara <[EMAIL PROTECTED]>: > James Strachan ha scritto: > > > > > 2008/5/8 Stefano Bagnara <[EMAIL PROTECTED]>: > > > > > I'm starting analysis on how to replace our default spool with ActiveMQ > and > > > [...] in James we currently have a single "message store" and we can > > > > > > "lock on a message" (so no other thread will take it) "retrieve it", > "update > > > and unlock it" (alter its state or state+content) or "remove it". How > would > > > you manage this with ActiveMQ? > > > > > > > > > With ActiveMQ you'd use a queue per state/maillet, remove it from the > > queue, do something with it then put it on some other queue(s) (either > > changed or the same message). The simple JMS/MOM model of sending to a > > queue or consuming from a queue turns out to be very fast; allowing a > > highly SEDA based asynchronous model to go really fast since there's > > no locking or leasing required - and messages can flow very > > asynchronously to boost throughput. > > > > What does it happen under the hood when I use so many queues? Is the > message fully written to disk each time I move it from a queue to another or > does it simply update a reference when it belongs to the same store?
Yeah, currently we do that. Another option is to use durable topics where a message is written once and all durable topic subscribers just get a kinda pointer to it. > I looked at the website and found an error in this page: > http://activemq.apache.org/camel/spring-xml-extensions.html > "An error occurred: Connection refused. The system administrator has been > notified." > I looked at the CWIKI sources > (http://cwiki.removeme_apache.org/confluence/display/CAMEL/Spring+XML+Extensions) > and I see this: > > {snippet:id=e3|lang=xml|url=activemq/camel/trunk/components/camel-spring/src/test/resources/org/apache/camel/spring/builder/spring_route_builder_test.xml} > Not sure but maybe you have to add svn.apache.org/repos/asf/ in front of > it? Unfortunately its due to the recent svn issues we've had at Apache. Snippets that were working totally fine in loads of confluence wikis are now totally borked :( https://issues.apache.org/jira/browse/INFRA-1607 feel free to vote for it :) > > > I understand this is a lot of questions, but I would really appreciate > any > > > hint, even partial. I'm collecting ideas :-) > > > > > > > :) > > > > Thank you! Your answers are even more than what I expected! You're > suggestion seems to be very very useful and I think you saved me weeks of > thoughts! You're most welcome! :) As an aside - for a while I've been pondering about adding a maillet support into Camel for easy Camel <-> JAMES integration. Something wacky to think about - which might be a bit too much Camel internals for now but bear with me.. Camel has a really neat extensible type conversion library... http://activemq.apache.org/camel/type-converter.html so that you can grab a message body or header as any type you like; be it a stream, string, byte[], Document, TrAX Source or whatever. Very handy for wiring things together! When you invoke beans in a route like this... f rom("activemq:SomeQueue").bean(SomeBean.class) we use the bean integration to figure out how to invoke the bean method from a message... http://activemq.apache.org/camel/bean-integration.html One of the little known things is that to invoke a bean, Camel first tries to coerce the bean into a Processor and if it can it uses that http://activemq.apache.org/camel/processor.html An example of this is the ActiveMQ component for Camel which allows you to invoke any JMS MessageListener within any Camel route - irrespective of what message is being used... http://activemq.apache.org/camel/activemq.html This is implemented by writing a Camel Type Converter that can turn any MessageListener instance into a Camel Processor - see the toProcessor() method https://svn.apache.org/repos/asf/activemq/trunk/activemq-core/src/main/java/org/apache/activemq/camel/converter/ActiveMQMessageConverter.java So we could have awesome JAMES integration in Camel by doing the same thing; creating converters between Camel's Message / Exchange types and JAMES/JavaMail's APIs for messages, or for creating a Processor from a Maillet so that we can invoke a Maillet within any Camel route - whether the message is coming from JMS, file system, database or JavaMail/JAMES etc > I'll start with your hints and I'll come back with more questions as soon > as I'll have rode the camel! ;-) Great! :) -- James ------- http://macstrac.blogspot.com/ Open Source Integration http://open.iona.com
