Mario, Thanks for the explanation. If I incorporate the JNDI configuration of amq, would Tomcat automatically start the broker? I need to create an embedded broker with network connectors. If I specify xbean configuration in JNDI, would Tomcat automatically create the broker and issue broker.start()?
Thanks, /U -------------- Original message ---------------------- From: "Mario Siegenthaler" <[EMAIL PROTECTED]> > I think the easiest way would be to use a broker that is started by > tomcat. This can be done using JNDI-configurations in the tomcats > server.xml (see http://activemq.apache.org/tomcat.html). > To connect to the broker you can either get the connection-factory via > JNDI (standard way) or just make a new ActiveMQ connection factory > pointing to vm://localhost (or whatever you named your broker). > You'll need to put the active-mq jar into the common/lib (or into the > server/lib if you only use jms-api functions and have the jms api with > common/lib) of your tomcat. Also you have to make sure that you don't > include a jms-api or activemq-jar in your war as that would cause the > feared ClassCastException. > > If you don't like the way I described above then you can also just put > the AMQ-jar in the common/lib (and not in any of the webapps) and > create the connection factory in each webapp for vm://localhost. This > will bring up a broker if there isn't already one running, so I > doesn't matter which webapp starts first. You'll not need any special > setup code. However I'm not sure where I'd put the activemq.xml > configuration file in that case. > > However I'd strongly recommend the first proposal, since it seems more > controllable and easier to configure. > > To your point 2: The class is serialized when it's passed around by > the broker (except you turn it off, of course only possible in the > vm-protocol). So you'll just have to make sure the thing is compatible > and you can put the jar X's in into both webapps and you don't need it > to put into common/lib. > > 3) No, I don't see any (technical) reason. However I'd recommend to > 'inject' the connection factory into the webapp, so the webapp is > completely agnostic to whether the broker is embedded or not. Else > you'll have more trouble moving them around. > > Mario > > On 6/18/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > > > > I am using activemq 4.1.1 on JDK6 with Tomcat 5.5.x. > > > > I have a couple of webapp contexts in a servlet container that use activemq > broker. > > I have been using an external broker but would like to embed the broker in > > the > > servlet container. I have the following questions. > > > > 1) Assume I have webapps A and B. Is it necessary that only one of the two > webapps > > assume the responsibility of starting the broker? I mean, I would like > > to > embed the > > starting of the broker in a jarfile that is shared by both the webapps. > > Its > hence easy for me > > to keep the jarfile agnostic to which webapp its operating in and execute > the broker start code > > at context startup. > > > > Stated simply, would this sequence cause two different brokers to attempt > > to > start? > > Should I build mechanisms to make sure the broker.start() is executed only > once? > > > > Webapp A: > > context load { // Time t > > Broker broker = new broker("tcp://localhost:61616"); > //pseudocode > > broker.start(); > > } > > > > Webapp B: > > context load { // Time t + 5 > > Broker broker = new broker("tcp://localhost:61616"); > //pseudocode > > broker.start(); > > } > > > > 2) Assume webapp A starts the broker. Also, let's say Class X is defined in > > a > jarfile > > common to both the webapps. > > > > Would this cause class cast exception if webapp B received an instance > > of > class X > > from the broker? (since I assume the broker would use the webapp A > classloader > > to load class X)? > > > > If so how do I avoid this class loading issue? Do I need to place the > activemq jarfiles > > as well as the application jarfiles which contains classes of the > > messages > dispatched > > over activemq to be in a shared system classpath common to both the > > webapp > contexts? > > > > 3) In a setup such as this where multiple webapps share the same embedded > broker, > > is it mandatory that they use an external broker? > > > > What are the other gotchas in using the embedded broker in this fashion? > > > > Regards > > > > /U > >
