Re: synchronize vs gate

I have a singleton in a web service that provides a collection and
self-updates it on a periodic basis:

doSelfUpdate()

  create temporary collection (time consuming)
  syncronize
    update temporary collection from current collection (fast)
    create temporary reference 'old' to current collection
    point current collection reference to temporary collection
  end syncronize
  do stuff with 'old' collection (time consuming)
  done

getCollection()
  synchronize
  just waiting on monitor
  end synchronize
  return collection
  done

It seems to me each thread accessing the getCollection method must
wait on the monitor every time it is accessed -- which is not what I
want. I just want to open and close the gate for a few milliseconds
while the self-update is being done. What do y'all think about
something like this:

boolean isBusy=false;

doSelfUpdate()
  create temporary collection
  isBusy=true;
    update temporary collection from current collection
    create temporary reference 'old' to current collection
    point current collection reference to temporary collection
  isBusy=false;
  do stuff with 'old' collection
  done

getCollection()
  maxWait=10000
  waited=0
  while(isBusy && waited <maxWait) {
     waited+=500
    if(waited>=MaxWait) log error;
     wait 500
     }
  return collection
  done

IMHO this means each thread consuming getCollection is a tiny bit
slower because it has a condition that must be tested, but as a group
they are not waiting in line for the monitor. Is this right?