Coursework 1 – Stock Exchange (Java)
Introduction
Itisworth 15%ofthemodulemark forthismodule.Itrequires 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 Expandeddescriptionoflimitpriceintheinputfile format to mention the type of value.
o Modifiedoffercompatibilitydescription-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 mustbenamedafteryourstudentIDnumber(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 runsJava1.8,thismeansyourprogrammustcompile 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 (notethecapitalization)inthatpackage 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 bookedforteaching. Donot waituntilthelastmomenttosubmit 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 submissionswilllose5percentagepoints perhour,roundedup 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 DoestheprogramworkwiththeexampleI/Ointhe question?
o Doestheprogramworkwithtypicalvalidinput?
o Doestheprogramcorrectlydealwithinputaround
boundary values?
o Doestheprogramcorrectlydealwithinvalidvalues? o Doestheprogramhandleerrorswithresourcesnot
being available (eg, a filename being wrong)?
o Doestheprogramoutputmatchtherequiredformat? o Doestheprogramperformanyspecifiedcalculations
correctly?
Asnotedinthesubmissionsection, ifyourprogramdoes
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 IsyourprogramanObject-Orienteddesign? o Areyoumakingappropriateusesofclasses,
inheritance, and interfaces?
o Areyoudealingwitherrorsappropriately?
o Areyouusingappropriatelevelsofaccessprotection? o Ifyouhavemanysimilarvalues,areyouusingarrays
(or equivalent) instead of many individual variables? Are you using appropriate Generics features to ensure type-safety?
o Areyouavoidingdeprecatedclassesandmethods? o Haveyoubrokenyourprogramdownintoseparate
functions?
o Areallyourfunctionargumentsbeingused?
o Ifyourfunctionsreturnvalues,aretheybeingused? o Areyouusingloopstoavoidrepeatingmanylinesof
code?
o Areyourif/switchstatementsmakingadifference,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 Anumberrepresentingthe offerID.Thenumberwill be a non-negative number which can be represented as a long value.
o Atimestampfortheoffer.Thenumberwillbea non-negative number which can be represented as a long value. Higher numbers represent later offers.
o Thecharacter’B’isitisaBUYoffer,’S’ifitis a sell order.
o Thelimitpricefortheoffer.IfitisaBUYorder, 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 Eachofthefieldsaboveareseparatedbyexactly1 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.
Yourprogrammusthaveaclasscalled OfferFile thatrepresents 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).
Offersmustberepresentedinyourprogrambyaclasscalled 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 exchangehastwo books,aBUYbookandaSELLbook,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.
Anewoffer executes ifthereisa compatible offerwaiting 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 objectrepresentingdetailsofthetrade.Thosedetails 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 TheBUYofferID
o TheSELLofferID
o Thepricethetradewasexecutedat.
o Eachofthefieldsaboveareseparatedbyexactly1
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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