OMP103_2020T2

https://ecs.wgtn.ac.nz/Courses/COMP103_2020T2/Assignment2 1/7 School of Engineering and Computer Science TeKuraMātaiPūkaha,Pūrorohiko COMP103 2020 Tri 2 Assignment 2: Using Collections

Due 14 Aug , 10 am

Goals and Assessment

This assignment will give you experience at writing programs using Collections.

The first part is a program that answers queries about Wellington trains and stations.

The second part is a very simple drawing program to which you must add an undo/redo facility.

The third and fourth parts have several methods using lists and stacks that will be automatically marked,

which you should do after the first two parts.

The assignment is worth 15% of your final mark.

Resources and links

Download Zip file containing the necessary code and data.

Getting online help

Video of lecture session with Demos of the assignments (go to minute 33 and minute 45).

Submit your answers

Marks and feedback

What To Hand In

By 10 am on 14 Aug, you need to submit:

WellingtonTrains.java, Station.java, TrainLine.java, TrainService.java,

Pencil.java, and any other classes you made for the Pencil program,

HTMLChecker.java

ListOfLists.java

If you haven't finished by three days after the due time (ie, by 10am Monday 17th) submit whatever you have

done at that point.

Part 1: Wellington Trains (Weight: 4% of your final mark)

WellingtonTrains is a program to answer queries about Wellington train stations, train lines and the

timetables for the train services on those lines.

2020/8/12 Assignment 2 - Courses/COMP103_2020T2 | ECS | Victoria University of Wellington

https://ecs.wgtn.ac.nz/Courses/COMP103_2020T2/Assignment2 2/7

(See https://www.metlink.org.nz/#plan for Metlink's equivalent program for the whole of the Wellington

Regional Transport system. Your program is not web-based, and doesn't need such a fancy interface.)

Stations, Lines, and Services: Your program has to deal with three kinds of information:

Train Stations

Train Lines: a sequence of stations. For example, the Wellington_Johnsonville line, which starts at

Wellington station, and ends at Johnsonville station, with 7 stations in between. To make things easier,

we treat the inbound and outbound as two separate train lines, so the Wellington_Melling line is different

from the Melling_Wellington line. (They have the same stations, but the sequence in one is the reverse

of the sequence in the other.)

Train Service: a schedule/timetable for a particular train running on a given train line. For example, the

11:32 train on the Wellington_Johnsonville line that leaves Wellington station at 11:32, leaves Crofton￾Downs at 11:40, ... gets in to Johnsonville at 11:55. 

A Train Service is specified by a sequence of times - the time that the train leaves the first station,

followed by the times that the train gets to each of the remaining stations on the line. Note that some

train services don't stop at every station on the line. If a train doesn't stop at a station, the corresponding

time will be -1.

Queries

The basic queries the program should be able to handle are the following:

1. List all the stations in the region

2. List all the stations in alphabetic order (by name).

3. List all the train lines in the region

4. List the train lines that go through a given station

5. List the stations along a given train line

6. Print the name of a train line that goes from a station to a destination station. (The train line must go the

correct direction.)

7. (Completion) Find the next train service for each line at a station after the specified time

8. (Completion) Find a trip between two stations (on the same line), after the specified time.

Find the train line, the time that next service on that line will leave the first station, the time that the

service will arrive at the destination station, and the number of fare zones the trip goes through.

9. (Completion) Find the 10 closest stations to a point on the map, listing the names and distances from

closest to furthest.

10. (Challenge:) More complex trips involve going from the first station to an exchange station on one train

line, then going from the exchange station to the second station on another train line. (In larger cities,

trips might require more than 2 train lines, but the Wellington region has a central hub, so you never

need more than two segments for a trip.)

Find the best trip (earliest arrival) between a starting station and a destination station. If the trip requires

two train lines, print out the starting time, the first train line, the exchange station, the arriving and

departing times at the exchange station, the second train line, and the arrival time at the destination, and

the total number of fare zones.

Data Files

There are a set of data files in the data sub directory that contain the information that your program needs

to load and then use.

data/stations.data contains one line of information about each station in the system: name, fare zone,

and location on the map. eg

Crofton-Downs 3 100 401

Note that there are no spaces in the station names - if the name has two parts, they are joined by a

hyphen.

data/train-lines.data contains the names of all the train lines, eg Melling_Wellington. Each line

is named by the station at the beginning of the line and the station at the end of the line, joined by an

underscore.

For each train line, there are two files:

one with the sequence of stations on the train line (eg data/Wellington_Johnsonville￾stations.data )

2020/8/12 Assignment 2 - Courses/COMP103_2020T2 | ECS | Victoria University of Wellington

https://ecs.wgtn.ac.nz/Courses/COMP103_2020T2/Assignment2 3/7

one with services (timetable) information (eg data/Wellington_Johnsonville-services.data )

Each line of a XXX_YYY-services.data file has a sequence of times for one train service on the train

line. The times are given in 24 hour time, with no ':' in the middle eg, 1437 is 2:37pm.

Data Structures Your WellingtonTrains program will need to load the data from the files into data structures inside the

program. A sensible way of organising the data inside your program will be to have

a collection of Stations (a Map, indexed by the names of the stations)

a collection of TrainLines (a Map, indexed by the names of the TrainLines)

For the Core of the assignment, you do not have to worry about the Train Services - just the Stations and

TrainLines.

We have provided Java Classes for Station, TrainLine, and TrainService objects to store

information about individual stations, train lines, and train services. Make sure that you read these classes

carefully and work out how to use them. They each have constructors, and methods to add data to the

object, and methods for accessing data in the object. Note that a TrainLine contains inside it a collection

of the TrainServices on that line, as well as a List of Stations, and a Station contains a collection of

the TrainLines that go through that station.

Template Code.

In addition to the Station.java , TrainLine.java , and TrainService.java classes, we have provided a

WellingtonTrains.java that contains just a few methods and fields. It contains a main method, a

doLoadData method, and a setupGUI method for creating a user interface like the one in the demo. You

do not need to use these methods unless you want to. The rest of the class is empty, and you will need to

write the methods that do all the work.

Suggested Algorithms for loading the datadistance from the

hub station

To Create the Map of Stations:distance from the hub station

Read the data from "data/stations.data"

For each line of the data,

construct a Station object using the data on the line

put the Station into the Map of Stations (the Station objects won't have any TrainLine

information at this point)

To Create the Map of TrainLines:

Read the list of train line names from "data/train-lines.data"

For each train line name

Construct a TrainLine object

Put the TrainLine object into the Map of TrainLines

For each station name in "data/XXX_YYY-stations.data

Look up the Station object in the Map of Stations,

Add the Station object to the stations in the TrainLine object,

Add the TrainLine object to the train lines in the Station object

To load the Train Service (timetable) information: [Completion only]

Read the list of train line names from "data/train-lines.data"

For each train line name

For each sequence of times in "data/XXX_YYY-services.data" (one line per sequence):

Construct a TrainService object

Add the TrainService object to the TrainLine object

2020/8/12 Assignment 2 - Courses/COMP103_2020T2 | ECS | Victoria University of Wellington

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For each time in the sequence of times,

Add the time to the TrainService object.

Core:

For the Core, your program should

Load the Station and Train Line data from the files into distance from the hub stationdata structures

Be able to answer the first 6 queries above.

Note that question 6 is a bit tricky because it has to check that the first station comes before the

destination station in the sequence of stations along the line.

Completion:

For the Completion, your program should also

Load the Train Service (timetable) data from the files into the data structures.

Be able to answer questions 7 and 8 above (both of which require the train service data).

Answer question 9 above, (which requires responding to the mouse).

Challenge:

For the Challenge, your program should also

Be able to answer question 10 above - finding the best trip, even if it requires an exchange between two

train lines.

Improve the interface and make the program better, eg by showing the stations and the lines on a map

(there are two png files with maps of the system that you can use).

Hints

Look at the data files carefully so you know what is there. The data is all from the

www.metlink.org.nz site (but cleaned up); looking at the site may help you understand the data

better.

Read the Station.java , TrainLine.java , and TrainService.java classes carefully to make sure you

know how to use them.

Sketch a diagram of the data structures, showing the Maps, a couple of Stations, a couple of TrainLines,

and a TrainService, in order to make sure you know how they are all related.

Part 2: Pencil (Weight: 3% of your final mark)

The Pencil program is a very simple drawing program that lets the use draw freehand lines on the graphics

pane with a "pencil". The drawing will consist of a collection of strokes, where each stroke is a freehand line

between the point the user pressed the mouse and the point the user released the mouse.

You are to add an undo and redo facility to Pencil. The undo button should remove strokes from the

drawing, one at a time, from the most recently added back to the first stroke. The redo button should "undo

the undo", by putting strokes back into the drawing after they have been undone. If the user draws a new

stroke after doing an undo or redo, the program will "forget" all the strokes that have been undone.

This is similar to the Sokoban program in Assignment 1, except that the base program is much simpler, and

you will have to do more work to make the undo work. You will almost certainly need a class to represent

strokes, and you may need to change the way the program works, more than you did for Sokoban.

Core:

2020/8/12 Assignment 2 - Courses/COMP103_2020T2 | ECS | Victoria University of Wellington

https://ecs.wgtn.ac.nz/Courses/COMP103_2020T2/Assignment2 5/7

Add the ability to undo the strokes

Completion:

Add the ability to redo strokes that have been undone and then undo and redo them again, (as long as

no new strokes have been created since the undo action).

Challenge:

Add the ability to change the colour and width of the pen, and ensure that undoing a stroke will take the

colour and width back to what it was before that stroke was added. Eg, if the user draws three black

strokes, then changes to red and draws two red strokes, then undoing the two red strokes will switch the

color back to black.

Part 3: HTMLChecker: (Automarked) (Weight: 2% of your final mark)

HTML files contain tags that specify the formatting of the document.

Tags are surrounded by < and >

Opening tags have a word immediately following the <

Closing tags have a forward-slash followed by a word after the <

For example: and

To be a properly constructed HTML file, all the tags should come in matching opening and closing pairs, and

they should be nested properly. For example

 

is valid, but