public void adjustTellerNumber() {
// This is actually a control system. By adjusting
// the numbers, you can reveal stability issues in
// the control mechanism.
// If line is too long, add another teller:
if (customers.size() / workingTellers.size() > 2) {
// If tellers are on break or doing
// another job, bring one back:
if (tellersDoingOtherThings.size() > 0) {
Teller teller = tellersDoingOtherThings.remove();
teller.serveCustomerLine();
workingTellers.offer(teller);
return;
}
// Else create (hire) a new teller
Teller teller = new Teller(customers);
exec.execute(teller);
workingTellers.add(teller);
return;
}
// If line is short enough, remove a teller:
if (workingTellers.size() > 1 && customers.size() / workingTellers.size() < 2)
reassignOneTeller();
// If there is no line, we only need one teller:
if (customers.size() == 0) while (workingTellers.size() > 1) reassignOneTeller();
}
public void run() {
try {
while (!Thread.interrupted()) {
TimeUnit.MILLISECONDS.sleep(rand.nextInt(300));
customers.put(new Customer(rand.nextInt(1000)));
}
} catch (InterruptedException e) {
System.out.println("CustomerGenerator interrupted");
}
System.out.println("CustomerGenerator terminating");
}
public void run() {
try {
while (!Thread.interrupted()) {
Customer customer = customers.take();
TimeUnit.MILLISECONDS.sleep(customer.getServiceTime());
synchronized (this) {
customersServed++;
while (!servingCustomerLine) wait();
}
}
} catch (InterruptedException e) {
System.out.println(this + "interrupted");
}
System.out.println(this + "terminating");
}