out.printf("time %5d %16s(%5d) leaves window %s\n", now,
customer.getTypeName(), customer.id, type);
++availableWindows[type.ordinal()];
assert hasAnySpareWindow();
Customer nextCustomer = getNextCustomer(type);
if (nextCustomer != null) {
out.printf("time %5d %16s(%5d) found for spare window %s\n",
now, nextCustomer.getTypeName(), nextCustomer.id, type);
assert nextCustomer.findSpareWindow(this);
nextCustomer.gotoWindow(this);
} else {
out.printf("time %5d %21s spare window %s\n", now, "", type);
}
}