CS Lab #2: Cruise Loaders Solution

Problem Description

The Kent Ridge Cruise Centre has just opened and you are required to design a program to decide how many loaders to buy based on a single-day cruise schedule.

Cruises

Each cruise has four attributes:

a unique string identifer, e.g. S1234

a time of arrival in HHMM format, e.g. 2359 denoting the cruise arriving at 11:59PM on that day the time needed to serve the cruise (in minutes), and the number of loaders needed to serve the cruise.

Every cruise must be served by loaders immediately upon arrival.

There are two types of cruises:

SmallCruise:

has an identifer that starts with an uppercase character S;
takes a fxed 30 minutes for a loader to fully load;

requires only one loader for it to be fully served;
BigCruise:
has an identifer that starts with an uppercase character B;
takes one minute to serve every 50 passengers;

requires one loader per every 40 meters in length of the cruise (or part thereof) to fully load

Loaders

Loaders have to be purchased to serve cruises. Each loader comprises two attributes:

a unique integer identifer

the cruise that it is currently serving

A loader will serve a cruise as soon as it arrives, and continues to do so until the service time has elapsed (i.e. it cannot serve a cruise while in the midst of serving another one).

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For example, if an incoming cruise arrives at 12PM, requires two loaders, and 60 min for it to be fully served, then, at 12PM, there must be two vacant loaders. These two loaders will serve the cruise from 12PM - 1PM. They can only serve another cruise from 1PM onwards.


Task

Your task is to determine the loader allocation schedule using the following steps:

For each cruise, check through the inventory of existing loaders, starting from the loader frst purchased, and so on;

The frst (or frst few) loaders available will be used to serve the cruise;

If there are not enough loaders, purchase new one(s) to serve the cruise.


Take note of the following assumptions:

Input cruises are presented chronologically by arrival time.


There can be up to 30 cruises in one day.

The number of loaders servicing a cruise will not exceed 9.

There are no duplicate cruises.

All cruises will arrive and be completely served within a single day..


Although this problem can be implemented procedurally, you are to model your solution using an object-oriented approach instead.

This task is divided into several levels. You need to complete ALL levels.



Level 1

Represent a Cruise

Design an immutable Cruise class to represent a cruise having a unique identifer string, the time of arrival as an integer, load the cruise as an integer, and the service time in minutes as an integer.

class Cruise {

private final String identifier;

private final int arrivalTime;

private final int numOfLoader;

private final int serviceTime;

...

}

Note that the time of arrival is in HHMM format. Specifcally, 0 or 0000 refers to 00:00 (12AM), 30 or 0030 refers to 00:30 (1 01:30 (1:30AM).

Implement a getServiceCompletionTime method, which returns the time the service completes (in number of minutes getArrivalTime method, which returns the arrival time (in number of minutes) since midnight.

For example, if the cruise arrives at 12PM (noon time), the arrival time is (12 * 60) = 720; the service completion time is 12 midnight, i.e. (12 * 60) + 30 = 750.

In addition, implement a getNumOfLoadersRequired method, which returns the number of loaders required to load the

A string representation of a cruise is in the form:

cruiseID@HHMM

The %0Xd format specifer might be of use to you, where the integer will be represented by an X-digit zero-padded number

String.format("%04d", 20);

would return the string 0020.

jshell> /open Cruise.java

jshell> new Cruise("A1234", 0, 2, 30)

$.. ==> A1234@0000

jshell> new Cruise("A2345", 30, 2, 30)

$.. ==> A2345@0030

jshell> new Cruise("A3456", 130, 2, 30)

$.. ==> A3456@0130

jshell> new Cruise("A3456", 130, 2, 30).getArrivalTime()

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$.. ==> 90







jshell> new Cruise("A3456", 130, 2, 30).getNumOfLoadersRequired()


$.. ==> 2



jshell> new Cruise("A3456", 130, 5, 30).getNumOfLoadersRequired()


$.. ==> 5



jshell> new Cruise("A1234", 0, 2, 30).getServiceCompletionTime()


$.. ==> 30



jshell> new Cruise("A1234", 0, 2, 45).getServiceCompletionTime()


$.. ==> 45



jshell> new Cruise("CS2030", 1200, 2, 100).getServiceCompletionTime()


$.. ==> 820



jshell> new Cruise("D1010", 2329, 2, 30).getServiceCompletionTime()


$.. ==> 1439



jshell> /exit







Check the format correctness of the output by running the following on the command line:

$ javac *.java

$ jshell -q < test1.jsh

Check your styling by issuing the following

$ checkstyle *.java




Level 2

Use Loaders to serve Cruises

Design an immutable Loader class to serve a cruise.

class Loader {

private final int identifier;

private final Cruise cruise;

...

}

Include the following in the Loader class:

a constructor that takes in an integer denoting its unique identifer, as well as the frst cruise that it serves.

a canServe(Cruise) method that returns true if the loader is available to serve the given cruise, or false othe a serve(Cruise) method to serve a given cruise. If the loader is available, the method returns the loader serving loader is returned

the methods getIdentifier() and getNextAvailableTime() to return the loader's identifer, and the next a

The string representation of each Loader is in the form:

Loader ID serving cruiseID@cruisearrivaltime

jshell> /open Cruise.java

jshell> /open Loader.java

jshell> new Loader(1, new Cruise("A1234", 0, 1, 30))

$.. ==> Loader 1 serving A1234@0000

jshell> new Loader(1, new Cruise("A1234", 0, 1, 30)).getIdentifier()

$.. ==> 1

jshell> new Loader(1, new Cruise("A1234", 0, 1, 30)).getNextAvailableTime()

$.. ==> 30
1
jshell> new Loader(1, new Cruise("A1234", 0, 1, 30)).canServe(new Cruise("A2345", 30,

$.. ==> true
30
jshell> new Loader(1, new Cruise("A1234", 0, 1, 30)).serve(new Cruise("A2345", 30, 1,

$.. ==> Loader 1 serving A2345@0030
30
jshell> new Loader(1, new Cruise("A1234", 0, 1, 30)).serve(new Cruise("A2345", 30, 1,

$.. ==> 60
1
jshell> new Loader(1, new Cruise("A1234", 0, 1, 30)).canServe(new Cruise("A2345", 10,

$.. ==> false
30
jshell> new Loader(1, new Cruise("A1234", 0, 1, 30)).serve(new Cruise("A2345", 10, 1,

$.. ==> Loader 1 serving A1234@0000
30
jshell> new Loader(1, new Cruise("A1234", 0, 1, 30)).serve(new Cruise("A2345", 10, 1,

$.. ==> 30


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jshell> new Loader(1, new Cruise("A1234", 0, 1, 30)).serve(new Cruise("A2345", 10, 1, 30


$.. ==> 1

jshell> /exit

Check the format correctness of the output by running the following on the command line:

$ javac *.java

$ jshell -q < test2.jsh

Check your styling by issuing the following

$ checkstyle *.java




Level 3

Represent Small Cruises

Design the SmallCruise class. The arguments of the constructor are its identifer, and time of arrival. Note that you shou class if you have implemented it properly.

jshell> /open Loader.java

jshell> /open Cruise.java

jshell> /open SmallCruise.java

jshell> new SmallCruise("S0001", 0).getArrivalTime()

$.. ==> 0

jshell> new SmallCruise("S0001", 0).getServiceCompletionTime()

$.. ==> 30

jshell> new SmallCruise("S0001", 0).getNumOfLoadersRequired()

$.. ==> 1

jshell> (Cruise) new SmallCruise("S0123", 1220)

$.. ==> S0123@1220

jshell> new Loader(1, new SmallCruise("S1245", 2330))

$.. ==> Loader 1 serving S1245@2330

jshell> new Loader(1, new SmallCruise("S1245", 2330)).canServe(new SmallCruise("S2345", $.. ==> false
jshell> new Loader(1, new SmallCruise("S1245", 2330)).serve(new SmallCruise("S2345", 235 $.. ==> Loader 1 serving S1245@2330
jshell> new Loader(1, new SmallCruise("S2030", 0))

$.. ==> Loader 1 serving S2030@0000

jshell> /exit

Check the format correctness of the output by running the following on the command line:

$ javac *.java

$ jshell -q < test3.jsh

Check your styling by issuing the following

$ checkstyle *.java





Level 4

Represent Big Cruises

Design the BigCruise class. The arguments of the constructor are its identifer, time of arrival, the length of the cruise, a order.

jshell> /open Loader.java

jshell> /open Cruise.java

jshell> /open SmallCruise.java

jshell> /open BigCruise.java

jshell> Cruise b = new BigCruise("B0001", 0, 70, 3000)

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jshell> b.getArrivalTime()





$.. ==> 0


jshell> b.getServiceCompletionTime()


$.. ==> 60


jshell> b.getNumOfLoadersRequired()


$.. ==> 2


jshell> new Loader(1, b).serve(b)


$.. ==> Loader 1 serving B0001@0000


jshell> new Loader(1, b).serve(b).getNextAvailableTime()

$.. ==> 60


jshell> new Loader(2, b)


$.. ==> Loader 2 serving B0001@0000


jshell> new Loader(3, b)


$.. ==> Loader 3 serving B0001@0000


jshell> new Loader(4, new BigCruise("B2345", 0, 30, 1450)).serve(new SmallCruise("S0000

$.. ==> Loader 4 serving S0000@0029


jshell> new Loader(5, new BigCruise("B3456", 0, 75, 1510)).serve(new SmallCruise("S0001

$.. ==> Loader 5 serving B3456@0000


jshell> /exit






Check the format correctness of the output by running the following on the command line:

$ javac *.java

$ jshell -q < test4.jsh

Check your styling by issuing the following

$ checkstyle *.java






Level 5

Output the loader allocation schedule

Write a method serveCruises(Cruise[]) that takes in an array of cruises, and outputs the allocation schedule of the cruises. Save the method in the fle level5.jsh.

You may assume that there are at most 30 cruises in one day, and the number of loaders servicing a cruise will not exceed

jshell>
/open Cruise.java
jshell>
/open SmallCruise.java
jshell>
/open BigCruise.java
jshell>
/open Loader.java
jshell>
/open level5.jsh
jshell>
Cruise[] cruises = {
...>
new SmallCruise("S1111", 1300)}
jshell>
serveCruises(cruises);
Loader 1 serving S1111@1300
jshell>
Cruise[] cruises = {
...>
new BigCruise("B1111", 1300, 80, 3000),
...>
new SmallCruise("S1111", 1359),
...>
new SmallCruise("S1112", 1400),
...>
new SmallCruise("S1113", 1429)}
jshell>
serveCruises(cruises);
Loader 1 serving B1111@1300
Loader 2 serving B1111@1300
Loader 3 serving S1111@1359
Loader 1 serving S1112@1400
Loader 2 serving S1113@1429
jshell>
Cruise[] cruises = {
...>
new SmallCruise("S1111", 900),
...>
new BigCruise("B1112", 901, 100, 1),
...>
new BigCruise("B1113", 902, 20, 4500),
...>
new SmallCruise("S2030", 1031),
...>
new BigCruise("B0001", 1100, 30, 1500),
...>
new SmallCruise("S0001", 1130)}
jshell>
serveCruises(cruises);
Loader 1 serving S1111@0900

Loader 2 serving B1112@0901

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Loader 3 serving B1112@0901


Loader 4 serving B1112@0901

Loader 2 serving B1113@0902

Loader 1 serving S2030@1031

Loader 2 serving B0001@1100

Loader 1 serving S0001@1130

jshell> /exit

Check the format correctness of the output by running the following on the command line:

$ javac *.java

$ jshell -q < test5.jsh

Check your styling by issuing the following

$ checkstyle *.java




Level 6

Recycled Loaders

The objective of this level is to determine whether your current implementation can be easily extended with minimal modif

The Cruise Centre has just introduced a new eco-friendly policy in an effort to go green. Their policy states that every third made of recycled materials (referred to as recycled loaders). These recycled loaders will go through a 60-minute long main unable to serve any cruise during this period.

For example, if a recycled loader serves a SmallCruise that arrives at 12:30PM, then the next time the loader can serve 60min after 12:30PM).

By modifying level5.jsh, incorporate the above with minimal modifcations to the fle level6.jsh.

jshell>
/open Cruise.java
jshell>
/open SmallCruise.java
jshell>
/open BigCruise.java
jshell>
/open Loader.java
jshell>
/open RecycledLoader.java
jshell>
/open level6.jsh
jshell>
Cruise[] cruises = {
...>

new BigCruise("B1111", 0, 60, 1500),
...>

new SmallCruise("S1112", 0),
...>

new BigCruise("B1113", 30, 100, 1500),
...>

new BigCruise("B1114", 100, 100, 1500),
...>

new BigCruise("B1115", 130, 100, 1500),
...>
}
new BigCruise("B1116", 200, 100, 1500)
...>


jshell>
serveCruises(cruises);
Loader 1

serving B1111@0000
Loader 2

serving B1111@0000
Recycled

Loader 3 serving S1112@0000
Loader 1

serving B1113@0030
Loader 2

serving B1113@0030
Loader 4

serving B1113@0030
Loader 1

serving B1114@0100
Loader 2

serving B1114@0100
Loader 4

serving B1114@0100
Loader 1

serving B1115@0130
Loader 2

serving B1115@0130
Recycled

Loader 3 serving B1115@0130
Loader 1

serving B1116@0200
Loader 2

serving B1116@0200
Loader 4

serving B1116@0200
jshell>
/exit

Check your styling by issuing the following

$ checkstyle *.java




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