Now, if the J2EE container used this (or a similiar) system in a
non-intrusive way, say via interceptors ala JBoss, that would be really
nice. You could have the turn on/off feature and not have to implement
or extend any classes/interfaces. Would make a nice addition to an admin
console as well.
Robert
Berin Loritsch wrote:
Damon E. Sorrentino wrote:
One thing WebSphere 5.0 supports is a diagnostic tracing service that
administrators and developers can enable or disable at the component
level. For example, WebSphere has an HTTP_Transport component with
several public classes:
com.ibm.ws.http.ChunkedInputStream
com.ibm.ws.http.ContentLengthInputStream
com.ibm.ws.http.HttpConnection
com.ibm.ws.http.HttpRequest
com.ibm.ws.http.HttpResponse
.
.
.
I'm not sure if this is necessarily related, but Avalon has an API
available
to instrument your code. It is quite configurable and works pretty well.
THe instrument APIs provide (1) a way to extend your code to expose
runtime
values, (2) a way to publish those (inside the same VM, or even
outside if
desired), and (3) a way to view the instrumentation. The client is a
Java
Swing based app that provides some really nice meters.
Another benefit besides just seeing the runtime state of your server is
also being able to tell the VM to do a garbage collection cycle. The
client
runs in its own JVM, and uses AltRMI to talk to the container code.
Best benefit of all:
Regardless of whether you choose to use Avalon for your container needs,
you can still use the instrumentation code. The Avalon containers
make it
a little easier because they are already integrated, but it is still an
extension.
Its pretty cool stuff, and it is pretty useful. Leif Mortenson is the
brainstormer behind it, and I have found him to be a rocket scientist
in regards to Java memory management. Not even the GUI client leaks
memory!
You can turn on and off the types of instruments you want to watch.
The administrator or developer can then enable certain types of
tracing within each class, i.e. entry/exit, event, and debug traces,
through their administration console web application. You can enable
any combination of these trace types.
This type of functionality proves useful when trying to run different
J2EE applications inside multiple application servers.
-damon
