/** Returns the number of idle {@link Executor}s that can start working immediately. */
public int countIdle() {
int n = 0;
for (Executor e : executors) {
if (e.isIdle()) n++;
}
return n;
}
private synchronized void setNumExecutors(int n) {
if (numExecutors == n) return; // no-op
int diff = n - numExecutors;
this.numExecutors = n;
if (diff < 0) {
// send signal to all idle executors to potentially kill them off
for (Executor e : executors) if (e.isIdle()) e.interrupt();
} else {
// if the number is increased, add new ones
addNewExecutorIfNecessary();
}
}
/** Returns true if this computer has some idle executors that can take more workload. */
public final boolean isPartiallyIdle() {
for (Executor e : executors) if (e.isIdle()) return true;
return false;
}
/** Returns true if all the executors of this computer are idle. */
@Exported
public final boolean isIdle() {
if (!oneOffExecutors.isEmpty()) return false;
for (Executor e : executors) if (!e.isIdle()) return false;
return true;
}