lab.util

Class Customer

java.lang.Object

lab.util.Customer

public class Customer
extends Object

A class for simulating a customer that arrives in a checkout queue. A customer is described using four values:

1. queue arrival time: the time when the customer first arrives at the back of the cashier's queue
2. cashier arrival time: the time when the customer reaches the front of the cashier's queue
3. check time required: the amount of time needed by the cashier to process this customer
4. departure time: the time when the customer completes the transaction and leaves the cashier's queue

The checkout time required is generated randomly when a customer is created. Specifically, the checkout time required is drawn from a normal distribution having mean equal to 60 seconds and standard deviation equal to 10 seconds. Practically, this means that it takes between 30 and 90 seconds of cashier time to process almost all customer transactions.

Constructor Summary

Constructors

Constructor and Description
Customer(double arrivalTime, Random rng) Create a customer that arrives at the checkout line(s) at arrivalTime.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object obj)
double	getCashierArrivalTime() Get the time (in seconds) when the customer reaches the front of the cashier's queue.
double	getCheckoutTimeRequired() Get the amount of cashier time (in seconds) needed by this customer.
double	getDepartureTime() Get the time (in seconds) when the customer completes the checkout process (i.e., leaves the cashier's queue).
int	getId()
double	getQueueArrivalTime() Get the time (in seconds) when the customer arrives at the back of the cashier's queue.
int	hashCode()
void	setCashierArrivalTime(double cashierArrivalTime) Set the time (in seconds) when the customer reaches the front of the cashier's queue.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Customer

public Customer(double arrivalTime,
        Random rng)

Create a customer that arrives at the checkout line(s) at arrivalTime. The random number generator rng is used to set the amount of cashier time needed to service this customer.

Parameters:

arrivalTime - the arrival time of the customer

rng - a random number generator

Precondition:

arrivalTime >= 0, rng != null

Method Detail

getQueueArrivalTime

public double getQueueArrivalTime()

Get the time (in seconds) when the customer arrives at the back of the cashier's queue.

Returns:

the queue arrival time of this customer

getCheckoutTimeRequired

public double getCheckoutTimeRequired()

Get the amount of cashier time (in seconds) needed by this customer.

Returns:

the amount of cashier time needed by this customer

getCashierArrivalTime

public double getCashierArrivalTime()

Get the time (in seconds) when the customer reaches the front of the cashier's queue.

Returns:

the arrival time of this customer

setCashierArrivalTime

public void setCashierArrivalTime(double cashierArrivalTime)

Set the time (in seconds) when the customer reaches the front of the cashier's queue. This has the side effect of also setting the departure time of this customer. The departure time of this customer is equal to cashierArrivalTime + this.getCheckoutTimeRequired()

Parameters:

cashierArrivalTime -

getDepartureTime

public double getDepartureTime()

Get the time (in seconds) when the customer completes the checkout process (i.e., leaves the cashier's queue).

Returns:

the time when the customer completes the checkout process

getId

public final int getId()

hashCode

public int hashCode()

Overrides:

hashCode in class Object

equals

public boolean equals(Object obj)

Overrides:

equals in class Object