How to know if a thread is busy?

Question

I have a main class and a Thread class that is a client.
I need this feature: client receive a data and pass it to main class; main class, by its methods, process this data; during processing, client could receive a new data, but if main class is still processing, client must reject.
The question is: how does the client knows if the main class is still elaborating?

Answer 1

In a thread I have put this method:
public synchronized void setIsProcessing(boolean
ean b) {
isProcessing = b;
then in a while I have:
synchronized (this) {}
if (!isProcessing) ....
else .....
I'm calling setIsProcessing from main class when I'm
starting doing anything, but if in a thread arrive
another things, it seems it queues it, and sends to
the main class when main has finished (it seems
isProcessing is never setting to true).
Why?Using the keyword synchronized in a non-static method is implicitly the same as using synchronized(this). If within the second bit of code you have an infinite loop that doesn't release the monitor then setIsProcessing() can never actually be executed by another thread as that requires acquiring the same monitor that you're not releasing.
::The main practical reason for "implements Runnable"
instead
::of "extends Thread" is that Java doens't support
multiple inheritance
:: of classes. So if you extend thread, you can't
extend anything else
:: but if you implement Runnable, yo can extend some
other class.
So, this is the reason of "implements"? Sorry for
this "academic" question ..If by that you mean as a solution to the problems of a single inheritance model then yes.