BankGuardRole

####Description Role inside of the bank that is responsible for escorting customers to tellers, defending the bank against robbers, and escorting customers out of the bank at closing time.

####Class Signature

public class BankGuardRole extends Role implements BankGuard {}

####Data

Queue<BankCustomerRole> waitingCustomers;
List<BankTellerRole> bankTellers;

####Scheduler

if Ǝ BankCustomerRole cust in waitingCustomers && Ǝ BankTellerRole teller in bankTellers ∋ teller.state == TellerState.UNOCCUPIED then,
    escortToTeller(cust, teller);
if Bank.getOpen == false then, // May not need this rule if we just allow customers to finish up
    escortCustomersOut();    

####Messages

public void msgHereToSeeTeller(BankCustomerRole customer) {
    // Add customer to queue
    waitingCustomers.add(customer);
    stateChanged();
}

public void msgDoneWithCustomer(BankTellerRole teller) {
    stateChanged();
}

####Actions

private void escortToTeller(cust, teller) {
    waitingCustomers.peek().msgGoToTeller(teller);
    waitingCustomers.remove();
}

private void escortCustomersOut(cust, teller) {
    for (BankCustomerRole cust : waitingCustomers) {
        waitingCustomers.peek().msgLeaveBank(cust);
        waitingCustomers.remove();
    }
}

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