how to detect end of thread/test in beanshell listener script?

[Wen, Fred TRAN:EX]

I use jmeter for function testing purpose (i.e. one thread loops once)
on a sequence of http samplers. So to me end of test/thread are the
same. I want to use beanshell listener to write something to stdout at
the end of the test. I've tried ctx.ThreadGroup.isDone() or
ctx.ThreadGroup.next() but they cannot distinguish if the listener is
invoked at the last sampler. 
Is there any way to achieve my objective?

Thanks
Fred Wen