/**
* The <code>addNode()</code> method adds a node to this synchronization group. This method should
* only be called before the <code>start()</code> method is called.
*
* @param t the simulator representing the node to add to this group
*/
public synchronized void addNode(Simulation.Node t) {
// if we already have this thread, do nothing
SimulatorThread st = t.getThread();
if (threadMap.containsKey(st)) return;
st.setSynchronizer(this);
// create a new synchronization event for this thread's queue
SynchEvent event = new SynchEvent(st);
threadMap.put(st, event);
// insert the synch event in the thread's queue
event.clock.insertEvent(event, period);
goal++;
}
/**
* The <code>removeNode()</code> method removes a node from this synchronization group, and wakes
* any nodes that might be waiting on it.
*
* @param t the simulator thread to remove from this synchronization group
*/
public synchronized void removeNode(Simulation.Node t) {
// don't try to remove a thread that's not here!
SimulatorThread st = t.getThread();
if (!threadMap.containsKey(st)) return;
synchronized (condition) {
SynchEvent e = (SynchEvent) threadMap.get(st);
e.removed = true; // just in case the thread is still running, don't let it synch
if (e.met) meet_count--;
if (stillWaiting(e.waitSlot)) {
// if this wait slot hasn't happened yet, we need to decrement wait_count
// and to decrement the number of waiters in that slot
e.waitSlot.numWaiters--;
wait_count--;
}
threadMap.remove(e);
goal--;
// signal any other threads (and wake waiters as necessary) but don't wait
signalOthers();
}
}
