You
are correct that the code can block if Tcl thread A blocks on doing some
work. To share a single thread amount multiple threads, the single thread
can provide non-blocking operations. For example:
Tcl
Thread A:
loop waiting for request from
other Tcl threads {
*
accepts the request with a notifier
*
call into Java code along with the notifier
* Java
code starts another Java worker thread
to do the work and returns immediately.
}
When the Java worker thread
finishes, use the
notifier object to wake up
anybody waiting.
Tcl
Thread X:
* create a
notifier
* send request to Tcl Thread A
along with the notifier
* wait on the
notifier
* gets the
result
This
mechanism uses multiple Java threads to do work in parallel. It also
provides a blocking interface for Tcl Thread X. There are a number
variation on this scheme depending on how you implement the
notifier.
Of
course, the problem is that the above is not part of TclBlend. If you are
short on time, then you may need to find a different
solution.
--
Jiang Wu
-----Original Message-----Jiang,
From: Mike Schwartz [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, July 18, 2000 11:19 AM
To: Jiang Wu
Cc: [EMAIL PROTECTED]
Subject: RE: [Tcl Java] tclBlend / tcl thread workaround
thanks for the response
You can do:Tcl Thread A -> package require java -> start JVM ... Tcl Thread B -> send request to Tcl thread A for Java work using
message passing on the event queue of ATcl Thread C -> send request to Tcl thread A for Java work ...
...
I don't think this will work because the Java-side code can have one thread
block while waiting for another thread's work to complete. For example:
Tcl Thread C above will not be able to run because Tcl Thread B has tied up the single connection to the JVM, and Tcl Thread B needs C to complete. I.e., the system would deadlock.
Any other thoughts appreciated. At this point I'm about to give up on using TclBlend and rework my software to use a different approach that avoids the whole tclblend/tclthreading problem
- Mike
