... . Of course i will have to lock the access to this method ..

Wouldn't that defeat the purpose of running the threads in parallel ?

I'm uncomfortable with your implementation of the locking to obtain and send data. Subtle bugs in this type code are notoriously difficult to notice/find/fix. My preference would be to use Thread::Queue, which will do all that for you, and probably simplify your main loop considerably. (The sample code, again).