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
