SWEN30006 Part A – Mailbot Blues solution




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You, an independent Software Contractor, have been hired by Robotic Mailing Solutions Inc. to provide some
much needed assistance in delivering their latest product to market, Automail. The Automail is an automated
mail sorting and delivery system designed to operate in large buildings that have dedicated Mail rooms. It
offers end to end sorting, storage and delivery of all mail within the large building, and can be tweaked to fit
many different installation environments. The system consists of four key components:
• A Mail Pool system which can hold a number of packages that has just arrived.
• A Delivery Robot (see figure below) which delivers mail items from the mail pool throughout the
• A Storage Unit, that is, a ‘backpack’ which is attached to the delivery robot. It can contain at most
four units.
• A Mail Sorting system which decides what packages should go into a robot’s backpack for delivery.
Figure 1: Artistic representation of our robot
The hardware of this system has been well tested. Unfortunately, the performance seen so far has been less
than optimal. Robotic Mailing Solutions has traditionally been a hardware company, and as such do not have
much software development experience. As a result, the strategies that they are using to organise the mail
and select the mail for delivery are very poor.
Your job is to apply your software engineering knowledge to develop new strategies for collecting and sorting
the mail to improve the performance of their system. Once you have created your strategies, you must
benchmark your strategies and provide feedback on your performance to Robotic Mailing Solutions.
Other useful information
• A mail item is labelled with a priority level (low, medium or high).
• A mail item has a size (large, medium or small).
– Large mail corresponds to four units
– Medium mail item corresponds to two units
– Small mail item corresponds to one unit
• A Storage Unit can contain at most four units in total.
• The Delivery Robot can be sent to deliver mail even if the Storage Unit is not full.
The Sample Package
You have been provided with a zip file containing all you will need to start your work for Robotic Mailing
Solutions. This zip file includes the full software simulation for the Automail product, which will allow you to
test your strategies in an experimental environment. This zip file provides you the application as an Eclipse
project. To begin:
1. Extract the zip files’s contents to your desired location
2. Open Eclipse
3. Import a new Eclipse project (File >> Import . . . >> General >> Existing Projects into Workspace)
4. Select the unzipped folder as the directory (and Next as required to complete the import)
5. Try running Simulation.java, you should see an output similar to this:
Figure 2: sample results
This will run the provided simulation and print output showing you the current performance of the Automail
system. This simulation should be used as a starting point in developing your benchmark program for your
strategies. Along with the code you have also been provided with compiled versions of the Javadoc for this
package, located in the doc folder. You should use this as your guide in developing your solution.
Please carefully study the sample package and ensure that you are confident you understand how it is set up
and functions before continuing. If you have any questions, please make use of the discussion board or ask
your tutor directly as soon as possible; it is assumed knowledge that you will be comfortable with the package
provided. In particular, you should note the scoring function used to calculate the cost of a delivery.
On Calculation of Stats
The sample package has the capability to run simulations and provide a stats summary after the simulation
has finished. It is important that you understand how these statistics are calculated so that there is no
misunderstanding that leads you to incorrect assumptions about the behaviour of your strategies. In particular,
the “Final Score” is the performance measure you need to improve: lower for this score is better.
Note By default, the simulation will run without a fixed seed, meaning the results will be random
on every run. In order to have a consistent test case, it would be good to specify the seed. You
can do this by editing the Run Configurations under Eclipse and adding an argument. Any integer
value will be accepted, i.e. 30006
Strategies Package Diagram
Seen below is a diagram of the strategies package. There are other classes included in this diagram as well.
Be aware that this does not represent all the classes in Simulation. This diagram is provided below to aid in
the understanding of the application.
Figure 3: Sample Diagram
The Task
As you can see, the current strategies used for the collection and sorting of mail are very simple and not at
all optimised for any particular use case. Thankfully, Robotic Mailing Solutions Inc. has made use of the
Strategy pattern (see reference here) to make their software more flexible and extensible in the future, by
creating a common interface for the collecting and sorting of mail.
Your task is to develop new collection and sorting strategies for mail within the Automail system. Robotic
Mailing Solutions inc. is particularly interested in improvements to the MailSorter, as internal testing has
shown this to be a significant factor on current performance. Specifically you must:
1. Create a class in the strategies package that implements the IMailPool interface.
2. Create a class in the strategies package that implement the IMailSorter interface.
3. Modify the class Automail (that is, revise Automail.java) so that it uses your MailPool and MailSorter
You must include in your code, comments explaining the rationale for your data structure and algorithm
choices and how these work toward achieving your goals for the MailSorter and MailPool implementations.
It is important to note that the strategies you provide must be different from those provided to you in the
sample package, and must achieve a better (lower) value for the “Final Score” statistic.
Note You will not be marked on the quality of your algorithms (that is, how well you achieve the
stated goal). This is not an algorithms subject so we do not expect optimal planning solutions.
You must, however, be able to demonstrate that you have made an attempt to address the problem
by organising the incoming mail in the mailpool and using that organisation in selecting mail in the
mailsorter. In addition, you must not violate the principle of the simulation by using information
that would not be available to simulated system, for example by using information about mail
items which have not yet been delivered to the mail pool.
We will be using our own version of the sample package during marking in which we will use our own fixed
seed. You will be submitting only the three files listed above, which must work with the rest of the sample
package. You should also test with different values, but should not otherwise modify the sample package.
Submission Verification
On the LMS, there is a file called build.zip which you need to extract to a folder and include two other files in
• Part A.zip (which is the original project file you downloaded off the LMS)
• submission.zip (a zip file which includes the three files you need to submit)
Refer to the README.txt file in build.zip for more details on building and running your program on the
University lab computers. In particular note the fact that you should develop your project solution in Eclipse,
not use the script for development!
If we cannot run your program you will receive at most 1 mark out of the 5 available for this project.
Note Your program must run on the University lab computers (using Java 8). It is your
responsibility to ensure you have tested in this environment before your submit your project.
Implementation Checklist
• Defined a class that implements the MailPool interface.
• Defined a class that implements the MailSorter interface
• Modified Automail.java so that the simulation uses the above classes
• All submitted code commented and of good quality (see below)
• Tested your program on a University computer to ensure compatibility
Marking Criterion
This project will account for 5 marks out of the total 100 available for this subject. These will be broken
down as follows:
Criterion Mark
Simulation compiles and runs correctly as per specification above 2.5 marks
Code quality, as described below. 2.5 marks
We expect to see good variable names, well commented functions, and inline comments for complicated code.
We also expect good object oriented design principles and functional decomposition. If we find any significant
issues with code quality we may deduct further marks.
We also reserve the right to award or deduct marks for clever or poor code quality on a case by case basis
outside of the prescribed marking scheme.
There is also a bonus mark available for submissions in the top 5% of performance. We will be judging
performance by comparing the “Final Score” statistic for your strategy. (The lower the score the better).
On Plagiarism
We take plagiarism very seriously in this subject. You are not permitted to submit the work of
others under your own name. This is an individual project. More information can be found here:
Submission Date
This project is due at 11:59pm on the 22nd of March. Any late submissions will incur a 1 mark penalty
per day unless you have an appropriate reason with supporting documents. If you have any issues with
submission, please email William at tiow@unimelb.edu.au, before the submission date.