[JBoss-dev] creating persistent MBeans dynamically

[Matt M. <mm...@ap...>]

Hi all,

  I have two questions here, a specific one relating to the subject, and a
more general question pertaining to the larger problem that I'm trying to
solve.

  First off, what is the best way to create new MBeans while the server is
running, in a persistent fashion?  Say, for example, I have a class Widget,
and a class WidgetFactory.  Suppose I create a WidgetFactoryMBean that has a
method

createNewWidget(String mbeanName, Object[] widgetFeatures);

  that has the purpose of creating a new instance of Widget, wrapping it in
a ModelMBean with the name <mbeanName>, and adding that mbean to the server.

  If I use the mbean server API for this, then the new MBean is loaded in
the VM, but dissapears on server restart.

  One solution for this, I imagine, would be, instead of using the mbean
server API, to actually write a *-service.xml file to the deploy folder each
time createNewWidget() is called.  Another solution might be to maintain
references to the widgets in the widget factory, and serialize and load them
through it. There are likely many more solutions.

  Have any of you tried something like this before? Is there code that does
this in the JBoss source tree?

  Now for the more general question...

  What I am trying to do is to allow dynamic generation of persistent
objects in the server.  These objects need to be exposed as web services,
and have access to databases, other web services, and JMS topics.  As
instances of the same class, all of these ojects will have the same
interface, yet will have different state, and need to expose this through
the web service protocol.  Once I have created these instances, I don't want
them to go away unless I specifically remove them.  If I restart the server,
they should show up again (technically different instances with identical
state).

  Ultimately, all I want to do is to say "create a widget named foo" via web
services, restart the server, say "tell me something about the widget named
foo" via web services, and get a response.

  I know that there are many ways to skin a cat.  Is there a better way
here?  Would EJB or some other structure make more sense?  I am generally
trying to stay away from EJB for the moment to avoid the overhead of RMI (I
don't need distributed objects), but I am open to any solution that makes
sense.

  - Matt