Question
NOT allowed to change anything outside GasStationSimulation 1. Introduction We want to write a program to simulate the behavior of a self-serve gas station. The
NOT allowed to change anything outside GasStationSimulation
1. Introduction
We want to write a program to simulate the behavior of a self-serve gas station.
The goal of this simulation is to collect statistical information of the gas
stations cars and gas pumps. A gas station consists of several pumps and a car
waiting line (i.e. a car queue). In each time unit, at most one new car arrives
at the gas station. If the car waiting line is too long, the car leaves without
getting gas; otherwise, the car gets into the waiting line. If all pumps are busy,
cars in the waiting lines must wait for a gas pump. If a pump is free and cars are
waiting, the first car in the waiting line gets the pump and begins pumping gas
immediately. When a car finishes using a pump, the car departs and the pump
becomes free. We will run the simulation through many units of time. At the end of
each time unit, your program should print out a "snap-shot" of queues, cars and
pumps. At the end of the program, your program should print out statistics and
conclude simulation.
2. Assumptions and Requirements
2.1. Assumptions
- At most one car arrival per time unit
- All numbers are positive integer numbers (>=0), except average values
should be displayed to two decimal places
- No time lost in between events:
a car arriving and entering waiting line
a car arriving and leaving without pumping gas
a car completing service and departing
a car leaving the waiting line, advancing to a pump and
beginning service
2.2. The limits of simulations parameters
- Maximum number of pumps 10
- Maximum simulation length 10000
- Maximum service duration 500
- Maximum car queue limit 50
- Probability of a new car 1% - 100%
2.3. Input parameters and car (random/file) data
- The following data are read at the beginning of the simulation:
int numGasPumps; // number of gas pumps.
int simulationTime; // time to run simulation
int carQSizeLimit; // car queue size limit
int chancesOfArrival; // probability of a new car (1 - 100)
int maxDuration; // maximum service (or pumping gas) duration per car
int dataSource; // data source: from file or random
- Sample input layout :
$ java PJ3.GasStationSimulation
*** Get Simulation Parameters ***
Enter simulation time (positive integer) : 10
Enter the number of gas pumps : 3
Enter maximum service time of cars : 5
Enter chances (0% < & <= 100%) of new car : 75
Enter car queue size limit : 2
Enter 1/0 to get data from file/rand() : 1 <-- see more details below
Enter filename : DataFile <-- for input 1 above
- In each time unit of simulation, your program will need two positive integers
numbers to compute (i) boolean anyNewArrival & (ii) int serviceDuration.
A user should have two options (1 or 0) to specify the source of those numbers:
For user input 1, numbers are read from a file. A filename should be provided
at the beginning of simulation. Each line in a datafile should contain two
positive numbers (> 0). A datafile should contain sufficient data for
simulationTime. In each time unit, anyNewArrival & serviceDuration are computed
in getCarData() as follows :
read data1 and data2 from the file;
anyNewArrival = (((data1%100)+1)<= chancesOfArrival);
serviceDuration= (data2%maxDuration)+1;
For user input 0, numbers are generated by method nextInt() in a Random
object, dataRandom, which should be constructed at the beginning of
simulation. In each time unit, anyNewArrival & serviceDuration are computed
in getCarData() as follows :
anyNewArrival = ((dataRandom.nextInt(100)+1) <= chancesOfArrival);
serviceDuration = dataRandom.nextInt(maxDuration)+1;
2.4. Input/Output information
- At the end of each time unit, you program should print out "snap-shot" of
simulation. At the end of simulation, you program need to print out end
of simulation report
- Sample run is provided at the end of Readme file.
2.5. Data structures and simulation algorithm
- I have defined package PJ3 with the Car, GasPump and GasStation classes,
you need to implement their methods. I also provide an outline of a
simulation program GasStationSimulation.java.
3. Compile and run program
- You need to download PJ3.zip file (with sample datafie) from ilearn.
- Compile programs (you are in directory containing Readme file):
javac PJ3/*.java
- Run programs (you are in directory containing Readme file):
// Run simulation
java PJ3.GasStationSimulation
4. Due Date
- 11:59:59PM, Sunday, November 26, 2017
- To submit your project, you need to zip all source files (*.java) into PJ3.zip
and upload PJ3.zip file to ilearn.
=====================================================================================
SAMPLE RUN
=====================================================================================
$ ls
DataFile PJ3 Readme
$ javac PJ3/*.java
$ java PJ3.Car
Car Info:CarID=1:ServiceDuration=30:ArrivalTime=40
$ java PJ3.GasPump
CarID=1:ServiceDuration=5:ArrivalTime=15
GasPumpID:5:startIntervalTime=0:endIntervalTime=0:total free time=0:total service time=0:Car:null
Start service car:
GasPumpID:5:startIntervalTime=20:endIntervalTime=25:total free time=20:total service time=0:Car:CarID=1:ServiceDuration=5:ArrivalTime=15
End service car:
GasPumpID:5:startIntervalTime=25:endIntervalTime=25:total free time=20:total service time=5:Car:CarID=1:ServiceDuration=5:ArrivalTime=15
Gas pump statistics data:
GasPump ID : 5
Total free time : 20
Total service time : 5
Total # of cars : 1
Average service time : 5.00
$ java PJ3.GasStation
[CarID=1:ServiceDuration=18:ArrivalTime=10, CarID=2:ServiceDuration=33:ArrivalTime=11, CarID=3:ServiceDuration=21:ArrivalTime=12, CarID=3:ServiceDuration=37:ArrivalTime=13]
===============================================
Remove car:CarID=1:ServiceDuration=18:ArrivalTime=10
Remove car:CarID=2:ServiceDuration=33:ArrivalTime=11
Remove car:CarID=3:ServiceDuration=21:ArrivalTime=12
Remove car:CarID=3:ServiceDuration=37:ArrivalTime=13
===============================================
freeGasPumpQ:[GasPumpID:1:startIntervalTime=0:endIntervalTime=0:total free time=0:total service time=0:Car:null, GasPumpID:2:startIntervalTime=0:endIntervalTime=0:total free time=0:total service time=0:Car:null, GasPumpID:3:startIntervalTime=0:endIntervalTime=0:total free time=0:total service time=0:Car:null, GasPumpID:4:startIntervalTime=0:endIntervalTime=0:total free time=0:total service time=0:Car:null]
===============================================
Remove free gas pump:GasPumpID:1:startIntervalTime=0:endIntervalTime=0:total free time=0:total service time=0:Car:null
Remove free gas pump:GasPumpID:2:startIntervalTime=0:endIntervalTime=0:total free time=0:total service time=0:Car:null
Remove free gas pump:GasPumpID:3:startIntervalTime=0:endIntervalTime=0:total free time=0:total service time=0:Car:null
Remove free gas pump:GasPumpID:4:startIntervalTime=0:endIntervalTime=0:total free time=0:total service time=0:Car:null
===============================================
freeGasPumpQ:[]
busyGasPumpQ:[]
===============================================
Assign cars to gas pumps
===============================================
Insert busy gas pumps to busy Q
busyGasPumpQ:[GasPumpID:1:startIntervalTime=13:endIntervalTime=31:total free time=13:total service time=0:Car:CarID=1:ServiceDuration=18:ArrivalTime=10, GasPumpID:2:startIntervalTime=13:endIntervalTime=46:total free time=13:total service time=0:Car:CarID=2:ServiceDuration=33:ArrivalTime=11, GasPumpID:3:startIntervalTime=13:endIntervalTime=34:total free time=13:total service time=0:Car:CarID=3:ServiceDuration=21:ArrivalTime=12, GasPumpID:4:startIntervalTime=13:endIntervalTime=50:total free time=13:total service time=0:Car:CarID=3:ServiceDuration=37:ArrivalTime=13]
===============================================
Remove busy gas pumps from busy Q
Remove busy gas pump:GasPumpID:1:startIntervalTime=31:endIntervalTime=31:total free time=13:total service time=18:Car:CarID=1:ServiceDuration=18:ArrivalTime=10
Remove busy gas pump:GasPumpID:3:startIntervalTime=34:endIntervalTime=34:total free time=13:total service time=21:Car:CarID=3:ServiceDuration=21:ArrivalTime=12
Remove busy gas pump:GasPumpID:2:startIntervalTime=46:endIntervalTime=46:total free time=13:total service time=33:Car:CarID=2:ServiceDuration=33:ArrivalTime=11
Remove busy gas pump:GasPumpID:4:startIntervalTime=50:endIntervalTime=50:total free time=13:total service time=37:Car:CarID=3:ServiceDuration=37:ArrivalTime=13
$ java PJ3.GasStationSimulation
*** Get Simulation Parameters ***
Enter simulation time (positive integer) : 10
Enter the number of gas pumps : 3
Enter chances (0% < & <= 100%) of new car : 75
Enter maximum service time of cars : 5
Enter car queue size limit : 2
Enter 0/1 to get data from Random/file : 1
Enter filename : DataFile
*** Start Simulation ***
Gas Pump #1 to #3 are ready...
---------------------------------------------
Time : 0
car #1 arrives with duration 5 units
car #1 wait in the car queue
car #1 gets a pump
pump #1 starts serving car #1 for 5 units
---------------------------------------------
Time : 1
car #2 arrives with duration 2 units
car #2 wait in the car queue
car #2 gets a pump
pump #2 starts serving car #2 for 2 units
---------------------------------------------
Time : 2
car #3 arrives with duration 5 units
car #3 wait in the car queue
car #3 gets a pump
pump #3 starts serving car #3 for 5 units
---------------------------------------------
Time : 3
No new car!
car #2 is done
pump #2 is free
---------------------------------------------
Time : 4
car #4 arrives with duration 3 units
car #4 wait in the car queue
car #4 gets a pump
pump #2 starts serving car #4 for 3 units
---------------------------------------------
Time : 5
No new car!
car #1 is done
pump #1 is free
---------------------------------------------
Time : 6
car #5 arrives with duration 3 units
car #5 wait in the car queue
car #5 gets a pump
pump #1 starts serving car #5 for 3 units
---------------------------------------------
Time : 7
car #6 arrives with duration 5 units
car #6 wait in the car queue
car #4 is done
pump #2 is free
car #3 is done
pump #3 is free
car #6 gets a pump
pump #2 starts serving car #6 for 5 units
---------------------------------------------
Time : 8
No new car!
---------------------------------------------
Time : 9
No new car!
car #5 is done
pump #1 is free
============================================
End of simulation report
# total arrival cars : 6
# cars gone-away : 0
# cars served : 6
*** Current GasPumps Info. ***
# waiting cars : 0
# busy gas pumps : 1
# free gas pumps : 2
Total waiting time : 0
Average waiting time : 0.00
Busy GasPumps Info. :
GasPump ID : 2
Total free time : 2
Total service time : 8
Total # of cars : 3
Average service time : 2.67
Free GasPumps Info. :
GasPump ID : 3
Total free time : 5
Total service time : 5
Total # of cars : 1
Average service time : 5.00
GasPump ID : 1
Total free time : 2
Total service time : 8
Total # of cars : 2
Average service time : 4.00
-------------------------------------------------------------------------------------------------------------------------------------------
package PJ3;
import java.util.*;
import java.io.*;
// You may add new functions or data in this class
// You may modify any functions or data members here
// You must use Car, GasPump and GasStation classes
// to implement your simulator
class GasStationSimulation {
// input parameters
private int numGasPumps, carQSizeLimit;
private int simulationTime, dataSource;
private int chancesOfArrival, maxDuration;
// statistical data
private int numGoAway, numServed, totalWaitingTime;
// internal data
private int carIdCounter; // car ID counter
private GasStation gasStationObj; // Gas station object
private Scanner dataFile; // get car data from file
private Random dataRandom; // get car data using random function
// most recent car arrival info, see getCarData()
private boolean anyNewArrival;
private int serviceDuration;
// initialize data fields
private GasStationSimulation()
{
// add statements
}
private void getUserParameters()
{
// read input parameters
// setup dataFile or dataRandom
// add statements
}
// Refer to step 1 in doSimulation
// this method is called for each unit simulation time
private void getCarData()
{
// get next car data : from file or random number generator
// set anyNewArrival and serviceDuration
// add statements
}
private void doSimulation()
{
// add statements
// Initialize GasStation
// Time driver simulation loop
for (int currentTime = 0; currentTime < simulationTime; currentTime++) {
// Step 1: any new car enters the gas station?
getCarData();
if (anyNewArrival) {
// Step 1.1: setup car data
// Step 1.2: check car waiting queue too long?
// if it is too long, update numGoaway
// else enter car queue
} else {
System.out.println("\tNo new car!");
}
// Step 2: free busy pumps that are done at currentTime, add to free pumpQ
// Step 3: get free pumps to serve waiting cars
} // end simulation loop
// clean-up - close scanner
}
private void printStatistics()
{
// add statements into this method!
// print out simulation results
// see the given example in project statement
// you need to display all free and busy gas pumps
// need to free up all cars in Car queue to get extra waiting time.
// need to free up all gas pumps in free/busy queues to get extra free & busy time
}
// *** main method to run simulation ****
public static void main(String[] args) {
GasStationSimulation gas_station_simulator=new GasStationSimulation();
gas_station_simulator.getUserParameters();
gas_station_simulator.doSimulation();
gas_station_simulator.printStatistics();
}
}
----------------------------------------------------------------------------------------------
// DO NOT ADD NEW METHODS OR NEW DATA FIELDS!
// DO NOT MODIFY METHODS OR NEW DATA FIELDS!
package PJ3;
import java.util.*;
//--------------------------------------------------------------------------
//
// Define simulation queues in a gas station. Queues hold references to Car &
// GasPump objects
//
// Car (FIFO) queue is used to hold waiting cars. If the queue is too long
// (i.e. > carQSizeLimit), car goes away without entering car queue
//
// There are several gas pumps in a gas station. Use PriorityQueue to
// hold BUSY gas pumps and FIFO queue to hold FREE gas pumps,
// i.e. a pump that is FREE for the longest time should start be used first.
//
// To handle gasPump in PriorityQueue, we need to define comparator
// for comparing 2 gasPump objects. Here is a constructor from Java API:
//
// PriorityQueue(int initialCapacity, Comparator comparator)
//
// For priority queue, the default compare function is "natural ordering"
// i.e. for numbers, minimum value is returned first
//
// User can define own comparator class for PriorityQueue.
// For GasPump objects, we like to have smallest end busy interval time first.
//
// The following class define compare() for two busy gas pumps :
class BusyGasPumpComparator implements Comparator
// overide compare() method
public int compare(GasPump o1, GasPump o2) {
return o1.getEndIntervalTime() - o2.getEndIntervalTime();
}
}
class GasStation {
// Private data fields:
// define one priority queue
private PriorityQueue
// define two FIFO queues
private Queue
private Queue
// define car queue size limit
private int carQSizeLimit;
// Constructor
public GasStation()
{
// add statements
}
// Constructor
public GasStation(int numGasPumps, int carQlimit)
{
// add additional statements
// use ArrayDeque to construct FIFO queue objects
// construct PriorityQueue object
// overide compare() in Comparator to compare busy GasPump objects
busyGasPumpQ= new PriorityQueue
new BusyGasPumpComparator());
// initialize carQlimit
// Construct GasPump objects and insert into FreeGasPumpQ
// assign gas pump ID from 1, 2,..., numGasPumps
}
// -------------------------------------------------
// freeGasPumpQ methods: remove, insert, empty, size
// -------------------------------------------------
public GasPump removeFreeGasPumpQ()
{
// remove and return a free gasPump
// Add statetments
return null;
}
public void insertFreeGasPumpQ(GasPump gasPump)
{
// insert a free gasPump
// Add statetments
}
public boolean emptyFreeGasPumpQ()
{
// is freeGasPumpQ empty?
// Add statetments
return false;
}
public int numFreeGasPumps()
{
// get number of free gasPumps
// Add statetments
return 0;
}
// --------------------------------------------------------
// busyGasPumpQ methods: remove, insert, empty, size, peek
// --------------------------------------------------------
public GasPump removeBusyGasPumpQ()
{
// remove and return a busy gasPump
// Add statetments
return null;
}
public void insertBusyGasPumpQ(GasPump gasPump)
{
// insert a busy gasPump
// Add statetments
}
public boolean emptyBusyGasPumpQ()
{
// is busyGasPumpQ empty?
// Add statetments
return busyGasPumpQ.isEmpty();
}
public int numBusyGasPumps()
{
// get number of busy gasPumps
// Add statetments
return 0;
}
public GasPump getFrontBusyGasPumpQ()
{
// get front of busy gasPumps
// "retrieve" but not "remove"
// Add statetments
return null;
}
// --------------------------------------------------------
// carQ methods: remove, insert, empty, size
// and check isCarQTooLong()
// --------------------------------------------------------
public Car removeCarQ()
{
// remove and return a car
// Add statetments
return null;
}
public void insertCarQ(Car car)
{
// insert a car
// Add statetments
}
public boolean emptyCarQ()
{
// is carQ empty?
// Add statetments
return false;
}
public int numWaitingCars()
{
// get number of cars
// Add statetments
return 0;
}
public boolean isCarQTooLong()
{
// is carQ too long?
// Add statetments
return false;
}
public void printStatistics()
{
System.out.println("\t# waiting cars : "+numWaitingCars());
System.out.println("\t# busy gas pumps : "+numBusyGasPumps());
System.out.println("\t# free gas pumps : "+numFreeGasPumps());
}
public static void main(String[] args) {
// quick check
GasStation sc = new GasStation(4, 5);
Car c1 = new Car(1,18,10);
Car c2 = new Car(2,33,11);
Car c3 = new Car(3,21,12);
Car c4 = new Car(3,37,13);
// insert cars into carQ
sc.insertCarQ(c1);
sc.insertCarQ(c2);
sc.insertCarQ(c3);
sc.insertCarQ(c4);
System.out.println(""+sc.carQ);
System.out.println("===============================================");
System.out.println("Remove car:"+sc.removeCarQ());
System.out.println("Remove car:"+sc.removeCarQ());
System.out.println("Remove car:"+sc.removeCarQ());
System.out.println("Remove car:"+sc.removeCarQ());
System.out.println("===============================================");
// remove gasPumps from freeGasPumpQ
System.out.println("freeGasPumpQ:"+sc.freeGasPumpQ);
System.out.println("===============================================");
GasPump p1=sc.removeFreeGasPumpQ();
GasPump p2=sc.removeFreeGasPumpQ();
GasPump p3=sc.removeFreeGasPumpQ();
GasPump p4=sc.removeFreeGasPumpQ();
System.out.println("Remove free gas pump:"+p1);
System.out.println("Remove free gas pump:"+p2);
System.out.println("Remove free gas pump:"+p3);
System.out.println("Remove free gas pump:"+p4);
System.out.println("===============================================");
System.out.println("freeGasPumpQ:"+sc.freeGasPumpQ);
System.out.println("busyGasPumpQ:"+sc.busyGasPumpQ);
System.out.println("===============================================");
// insert car to gas pumps
p1.switchFreeToBusy (c1, 13);
p2.switchFreeToBusy (c2, 13);
p3.switchFreeToBusy (c3, 13);
p4.switchFreeToBusy (c4, 13);
System.out.println("Assign cars to gas pumps");
// insert gas pumps into busyGasPumpQ
System.out.println("===============================================");
System.out.println("Insert busy gas pumps to busy Q");
sc.insertBusyGasPumpQ(p1);
sc.insertBusyGasPumpQ(p2);
sc.insertBusyGasPumpQ(p3);
sc.insertBusyGasPumpQ(p4);
System.out.println("busyGasPumpQ:"+sc.busyGasPumpQ);
System.out.println("===============================================");
// remove gas pumps from busyGasPumpQ
System.out.println("Remove busy gas pumps from busy Q");
p1=sc.removeBusyGasPumpQ();
p2=sc.removeBusyGasPumpQ();
p3=sc.removeBusyGasPumpQ();
p4=sc.removeBusyGasPumpQ();
p1.switchBusyToFree();
p2.switchBusyToFree();
p3.switchBusyToFree();
p4.switchBusyToFree();
System.out.println("Remove busy gas pump:"+p1);
System.out.println("Remove busy gas pump:"+p2);
System.out.println("Remove busy gas pump:"+p3);
System.out.println("Remove busy gas pump:"+p4);
}
};
---------------------------------------------------------------------------------------------------------------------------
// DO NOT ADD NEW METHODS OR DATA FIELDS!
// DO NOT MODIFY METHODS OR DATA FIELDS!
package PJ3;
class GasPump {
// pump id and current car which is served by this gas pump
private int pumpId;
private Car currentCar;
// start time and end time of current interval
private int startIntervalTime;
private int endIntervalTime;
// for keeping statistical data
private int totalFreeTime;
private int totalBusyTime;
private int totalCars;
// Constructor
GasPump()
{
this(-1);
}
// Constructor with gas pump id
GasPump(int gasPumpId)
{
// add statements
}
//--------------------------------
// accessor methods
//--------------------------------
int getPumpId ()
{
return pumpId;
}
Car getCurrentCar()
{
return currentCar;
}
int getEndIntervalTime()
{
return endIntervalTime;
}
//---------------------------------
// GasPump State Transition methods
//---------------------------------
// State transition : FREE interval -> BUSY interval:
void switchFreeToBusy (Car currentCar, int currentTime)
{
// Main goal : switch from free interval to busy interval
//
// steps : end Free interval - set endIntervalTime, update totalFreeTime
// start Busy interval - set startIntervalTime , endIntervalTime, currentCar,
// update totalCars
// add statements
}
// State transition : BUSY interval -> FREE interval:
Car switchBusyToFree ()
{
// Main goal : switch from busy interval to free interval
//
// steps : end Busy interval - update totalBusyTime
// start Free interval - set startIntervalTime
// return currentCar (just done with service)
// add statements
return null;
}
//-------------------------------------------------------------------
// Update totalBusyTime and totalFreeTime at the end of simulation
//
// use these method at the end of simulation to update gas pump
// totalFreeTime or totalBusyTime data in free and busy queues
//------------------------------------------------------------------
void updateTotalFreeTimeEndSimulationTime(int endsimulationtime)
{
// add statements
}
void updateTotalBusyTimeEndSimulationTime(int endsimulationtime)
{
// add statements
}
//--------------------------------
// Print statistical data
//--------------------------------
void printStatistics ()
{
// print gasPump statistics, see project statement
System.out.println("\t\tGasPump ID : "+pumpId);
System.out.println("\t\tTotal free time : "+totalFreeTime);
System.out.println("\t\tTotal service time : "+totalBusyTime);
System.out.println("\t\tTotal # of cars : "+totalCars);
if (totalCars > 0)
System.out.format("\t\tAverage service time : %.2f%n ",(totalBusyTime*1.0)/totalCars);
}
public String toString()
{
return "GasPumpID:"+pumpId+
":startIntervalTime="+startIntervalTime+
":endIntervalTime="+endIntervalTime+
":total free time="+totalFreeTime+
":total service time="+totalBusyTime+
":Car:"+currentCar;
}
public static void main(String[] args) {
Car mycar = new Car(1,5,15);
System.out.println(mycar);
GasPump mypump = new GasPump(5);
System.out.println(mypump);
System.out.println(" Start service car:");
mypump.switchFreeToBusy (mycar, 20);
System.out.println(mypump);
System.out.println(" End service car:");
mypump.switchBusyToFree();
System.out.println(mypump);
System.out.println(" Gas pump statistics data:");
mypump.printStatistics();
}
};
---------------------------------------------------------------------------------------------------
// DO NOT ADD NEW METHODS OR DATA FIELDS!
// DO NOT MODIFY METHODS OR DATA FIELDS!
package PJ3;
class Car
{
private int carId;
private int serviceDuration;
private int arrivalTime;
// default constructor
Car()
{
carId = -1;
serviceDuration = -1;
arrivalTime = 0;
}
// constructor to set carId, serviceDuration,
// and arrivalTime
Car(int CID, int serviceTime, int arriveTime)
{
carId = CID;
serviceDuration = serviceTime;
arrivalTime = arriveTime;
}
int getServiceDuration()
{
return serviceDuration;
}
int getArrivalTime()
{
return arrivalTime;
}
int getCarId()
{
return carId;
}
public String toString()
{
return "CarID="+carId+":ServiceDuration="+serviceDuration+":ArrivalTime="+arrivalTime;
}
public static void main(String[] args) {
// quick check!
Car mycar = new Car(1,30,40);
System.out.println("Car Info:"+mycar);
}
}
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