Microsoft Word – coursework1（JAVA）副本.docx
AE1PGP Coursework 1 – Stock Exchange
(Java)
Introduction
This is the first AE1PGP Coursework. It is worth 15% of the module
mark for this module. It requires you to use Object-Oriented
Programming and the Java programming language to design and write
a program that will function as a simple stock exchange, reading
orders from a file, processing them, and then writing the results
to another file. The deadline for this exercise is16:00 on
Wednesday 29th March 2017.
Read the entire document before beginning the exercise.
Version History
• Version 1.0 – 2017-03-15 – Original version.
• Version 1.1 – 2017-03-17 – Current version.
o Expanded description of limit price in the input file
format to mention the type of value.
o Modified offer compatibility description – should
also include limit prices which are equal; added rule
if multiple offers both have the same price and
timestamps.
Submission
You must submit a single zip file containing Java source code
file(s) containing all your code for this exercise. The zip file
must be named after your student ID number (ie, 6512345.zip) and
must not require any other files outside of the standard Java
platform classes which are always available. The first line of
each file should be a comment which contains your student ID number,
username, and full name, of the form:
// 6512345 zy12345 Joe Blogs
I will unzip your zip file into a new directory. Your program must
then compile without warnings or errors when I use the command
javac -d . *.java
This command will be run on our Linux server cs-linux.
As cs-linux runs Java 1.8, this means your program must compile
with Java 1.8 and must not use features or classes only available
in later versions of Java. If it does not compile, for any reason,
then you will lose all the marks for testing (common reasons in
the past have been submitting a file with the wrong filename, or
developing your solution on your personal computer without having
tested it on our Linux server). If the file compiles but has
warnings then you will lose some marks for not correcting the
warnings.
All your source files must be part of a package. That package
should be called unnc.cs.zy12345where zy12345 should be
replaced with your username. You must also have a public class
calledStockExchange (note the capitalization) in that package
which contains your program’s main method. Your program will
be run with the command (with the appropriate username
substituted),
java unnc.cs.zy12345.StockExchange inputfilename outputfilename
followed by any command-line arguments specified by the question.
If your program does not run with this command then you will lose
all testing marks as specified above.
The completed source code file should be uploaded to the
Coursework 1 Submission link on the AE1PGP Moodle page. You may
submit as many times as you wish before the deadline (the last
submission before the deadline will be used). After the deadline
has passed, if you have already submitted your exercise then you
will not be able to submit again. If you have not already submitted
then you will be allowed to submit once.
Remember that you can only access the Linux server from the
designated labs in SEB and SSB and that these labs are also heavily
booked for teaching. Do not wait until the last moment to submit
as you may find you cannot get into any of the rooms to access
your source code files. Not being able to access the machine due
to lack of planning is not an extenuating circumstance.
Late submissions: AE1PGP late submission policy
is different from the standard university policy. Late
submissions will lose 5 percentage points per hour, rounded up
to the next whole hour. This is to better represent the large
benefit a small amount of extra time can give at the end of a
programming exercise. No late submissions will be accepted more
than 24 hours after the exercise deadline. If you have extenuating
circumstances you should file them before the deadline.
Plagiarism
You should complete this coursework on your own. Anyone suspected
of plagiarism will be investigated and punished in accordance with
the university policy on plagiarism (see your student handbook
and the University Quality Manual). This may include a mark of
zero for this coursework.
You should write the source code required for this assignment
yourself. If you use code from other sources (books, web pages,
etc), you should use comments to acknowledge this (and marks will
be heavily adjusted down according to the amount of original
work).
You must not copy or share source code with other students. You
must not work together on your solution. You can informally talk
about higher-level ideas but not to a level of detail that would
allow you all to create the same source code.
Remember, it is quite easy for experienced lecturers to spot
plagiarism in source code. If you are having problems you should
ask questions rather then plagiarize. If you are not able to
complete the exercise then you should still submit your incomplete
program as that will still get you some of the marks for the parts
you have done (but make sure your incomplete solution compiles
and partially runs!).
Marking
The marking scheme will be as follows:
• Tests (50%): Your program should correctly implement the
task requirements. A number of tests will be run against your
program with different input data designed to test if this
is the case for each individual requirement. The tests
themselves are secret but general examples of the tests
might be:
o Does the program work with the example I/O in the
question?
o Does the program work with typical valid input?
o Does the program correctly deal with input around
boundary values?
o Does the program correctly deal with invalid values?
o Does the program handle errors with resources not
being available (eg, a filename being wrong)?
o Does the program output match the required format?
o Does the program perform any specified calculations
correctly?
As noted in the submission section, if your program does
not compile then you will lose all testing marks.
• Appropriate use of language features (40%): Your program
should use the appropriate Java language features in your
solution. You can use any language features or techniques
that you have seen in the course, or you have learned on your
own, as long as they are appropriate to your solution.
Examples of this might be:
o Is your program an Object-Oriented design?
o Are you making appropriate uses of classes,
inheritance, and interfaces?
o Are you dealing with errors appropriately?
o Are you using appropriate levels of access protection?
o If you have many similar values, are you using arrays
(or equivalent) instead of many individual variables?
Are you using appropriate Generics features to ensure
type-safety?
o Are you avoiding deprecated classes and methods?
o Have you broken your program down into separate
functions?
o Are all your function arguments being used?
o If your functions return values, are they being used?
o Are you using loops to avoid repeating many lines of
code?
o Are your if/switch statements making a difference, or
is the conditions always true or false making the
statement pointless?
• Source code formatting (10%): Your program should be
correctly formatted and easy to understand by a competent
Java programmer, using the standard shown in the lectures
and textbook. This includes, but is not limited to,
indentation, bracketing, class/variable/method naming, and
use of comments. See the lecture notes, and the example
programs for examples of correctly formatting programs.
Late Submissions: see submission section above.
Task
You have to write a program that will act as a stock exchange by
loading in a list of buy and sell offers from a file, and matching
them together to decide which offers execute with each other
according to an algorithm given below. Once it has processed all
the offers, it will write a log of the completed trades to another
file.
This program must be non-interactive. It should take two
command-line arguments. The first is the filename of the input
file of offers. The second is the filename that the output log
file of completed trades should be written to. If a file already
exists with that filename then it should be overwritten with the
new log file. If the program cannot read the input file or write
the output file, the program should print an error message either
“Cannot read input file” or “Cannot write output file” and exit
with return code 1. If it can read the input file but it’s format
is incorrect, it should print a different error message (see
later). The main method must be in a public class
called StockExchange class.
The input file lists all the offers that are being submitted to
the stock exchange. The format of the input file is as below:
• It is a text file, lines are separated by a single ‘\n’
character.
• Blank lines should be ignored anywhere in the file.
• Each offer is one line of text.
• The format of each offer line is:
o A number representing the offer ID. The number will
be a non-negative number which can be represented as
a long value.
o A timestamp for the offer. The number will be a
non-negative number which can be represented as
a long value. Higher numbers represent later
offers.
o The character ‘B’ is it is a BUY offer, ‘S’ if it is
a sell order.
o The limit price for the offer. If it is a BUY order,
this represents the maximum price the offer is willing
to pay. If it is a SELL order, this represents the
minimum price the offer is willing to sell at. The
number will be a non-negative integer which can be
represented as an int value.
o Each of the fields above are separated by exactly 1
space character.
• If the format of the file is invalid, the program should
print the error message “Invalid input file” and exit with
code 2.
Your program must have a class called OfferFile that represents
the input file. This class should have a constructor which takes
1 argument, the input filename. It should also have a way for other
objects to access each offer in the file, one-by-one (for example,
by a nextOffer method, or using the Iterator design pattern).
Offers must be represented in your program by a class called Offer.
You should get instances of this class from OfferFile in some
way you have decided above. The class should encapsulate the data
for an individual offer.
Your program should also have a class called Exchange which
represents the stock exchange state and behaviour. The stock
exchange has two books, a BUY book and a SELL book, representing
all the waiting buy and sell offers which have not been completed.
Each book is sorted by price and time. The BUY book is ordered
by highest price first, the SELL book by lowest price first, as
described by priority below. The exchange should have a method
to take a new offer and try and execute that order. If it is
executed then it should store a Trade object representing a
record of the details of the trade. If it is not executed then
the new offer should be added to the appropriate waiting book in
the appropriate place.
A new offer executes if there is a compatible offer waiting
in the exchange. A offer is compatible if,
• For a new BUY offer, there is a SELL offer which has a limit
price equal or below the BUY offer limit price.
• For a new SELL offer, there is a BUY offer which has a limit
price equal or above the SELL offer limit price.
When 1 or more compatible offers exist, the waiting offer with
the highest priority is selected. Priority is ordered by limit
price (lowest compatible sell price is highest priority for
waiting SELL offers, highest compatible buy price is highest
priority for waiting BUY offers). If there are multiple offers
at the same price, the priority goes in order of the offer
timestamps. If the timestamps are also the same, the program can
arbitrarily select which offer to match.
When the offer executes, the price of the trade is equal to the
price of the waiting order it was matched with. For example, if
a BUY at 100 offer is received and there is a waiting SELL at 70
offer, then the trade executes at the price of 70 because that
is the price of the offer waiting on the book.
As noted above, when a trade executes, you should store
a Trade object representing details of the trade. Those details
should be the BUY order ID, the SELL order ID, and the price the
order actually executed at.
Once the program has gone through all the offers in the input file
and tried to execute them, it should write the output file
containing a log of all the trades that happened. The format of
the output file is as below:
• It is a text file, lines should be separated by a single ‘\n’
character.
• Each completed trade is one line of text.
• Trades should appear in the file in the order they were
executed, with the first trade at the top of the file, the
last at the bottom of the file.
• The format of each trade line is:
o The BUY offer ID
o The SELL offer ID
o The price the trade was executed at.
o Each of the fields above are separated by exactly 1
space character.
Remember the submission notes at the top – each of your classes
and interfaces must be in a separate file, and written inside a
package with the correct name, and zipped together in the correct
way. You should submit all the classes specified above and any
others you decided to write in your solution. Your zip file should
not contain any “.java” files that are not part of your final
submission. If you are unsure you have done it correctly, try
downloading your submission from Moodle, unzipping it in a new
location, and trying to compile and run it with the given commands.
If you are still unsure, ask in the labs.
Example input/output
A proportion of test cases for marking will be released on 22nd
March 2016. You program should produce the expected answer for
all those test cases. There will be additional test cases used
in marking that are not released.
Hints
• You will need to learn about some new classes for this
exercise. The textbook and the Java API documentation will
be useful references.
• Where possible, use existing classes and interfaces in your
program. In particular, consider the classes and interfaces
in the Collections framework when you need to store multiple
objects.
• The task specifies some of the classes, constructors,
methods, and state that must exist for each class. You are
likely to need to add extra methods, state, and have other
classes as well in your solution. You may add whatever else
you need for your design, as long as you use the classes
specified in the task with it.
• Make sure not to accidentally store/write the buy and sell
offer IDs in the wrong order! You will need to test your
program with a variety of orders, calculating the output by
hand to compare against your program.
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