May threads force other threads to sleep?!

Question

Hi all,
Really hope someone may help me!! I have four classes. The master program, class A, calls class B (not a thread) when an action occurs. The actions effect the behaviour of the third class ObjectThread. B may sometime force the ObjectThread thread to sleep for some time (not predetermined). Then when it's time, B awakens ObjectThread, which continues.
The problem is that I don't want B to lock while an ObjectThread is sleeping. Hence I have created class C (also a thread), which is called only when ObjectThread needs to sleep. Input to C is a handle to the respective ObjectThread. But I can't get class C to force ObjectThread to sleep! I've tried not having C as a thread, but merely as a simple class, then it works but the whole thing locks.
How can I make the C thread perform first:
handleToObjectThread.sleep (); (this I guess may be managed with while loops)
then whenever I feel like it in the B class
handleToObjectThread.interrupt ();
Please help!!
/ jez

Answer 1

i assume that ObjectThread has a loop in its run() method...
why not at the start or end of the loop, get it to check to see if it should be sleeping
then class B could just set a flag (boolean) or an int (time to sleep) in ObjectThread
so..
ObjectThread extends Thread{
private boolean sleep=false;
public void run(){
  while(doit){
   if(sleep){
    try{
     while(!sleep){
      Thread.sleep(whatever);
    catch(InterruptedException ie){};
   //rest of loop
public void goToSleep(){
  sleep=true;
public void wakeUp(){
  sleep=false;
interrupt(); // only if you need to wake immediately
}