Caesar Pang - Project Portfolio

Introduction

Hi! My name is Caesar Pang. I’m currently a Year 2 student studying Computer Science, in School of Computing (SOC) in NUS.

This portfolio page aims to document the contributions I have made in the development of TutorAid, which is a project that my team and I completed for the module CS2103T. This project has definitely taught me many skills that are extremely relevant in the real world and in the future. It has allowed me to be a more competent and knowledgeable software engineer.

PROJECT: TutorAid

Overview

TutorAid is an easy-to-use Command Line Interface (CLI) [i.e issue commands to the program by typing in text inputs ] based application with a Graphical User Interface (GUI) [i.e. allows users to interact with the application through visual and graphical elements] that helps to makes the lives of tutors easier by organizing their workflow and making tutors more efficient. With a myriad of features such as student profile tracking, earnings, reminders, notes and tasks all in one application, tutors no longer have to search through their notes one-by-one excruciatingly.

The features of TutorAid has been well-thought out, keeping in mind the necessities and wants of tutors alike. To meet the exact needs of our target audience, we have conducted several surveys to ask current tutors what they would like in an application and thus, TutorAid was created. All of TutorAid’s features and implementations are well documented with proper visualization in guides for users and developers respectively.

Figure 1. A view of TutorAid

Role

My main role was to prototype and develop the Login feature and the Earnings Tracker feature. The login command required me to think of how to put up a login window that only shows the main window when the user has logged in successfully. It also required me to think of how to encrypt the passwords stored and how to check whether they are valid as well. I also did the Earning feature where it tracks what earnings you have earned throughout the weeks. Developing it further, I decided to add a automated earnings addition to save the users time. It has a claim status that allows you to see if you have claimed your earnings from your respective faculties.

Summary of contributions

Largest Enhancement: Auto addition of earnings.
- What it does: It allows the user to auto add all of the earnings of the day (provided that the earnings is a weekly routine), into the earnings list with only one short auto command.
- Justification: This feature improves the product significantly because as a Tutor, it is normal to have tutorials or labs or consultations to give at the same day of the week, every week. If a tutor, for example, has many lessons in a day to teach, he/she has to add the earnings into the list one by one, which is extremely hard and tedious to do. If the tutor has added the earnings into the list once already, the tutor can repeat this earnings by invoking the weekly_earnings command and the number of times to add into the list. Afterwards, the tutor just has to invoke the auto command on the day itself to auto add all his routine lessons.
- Implementation: This enhancement alters how TutorAid is used. Instead of just being a normal, "key in earnings" tracker, the addition of such a feature has helped to ease the use of earnings tracking for the users. This is facilitated by the use of a HashMap in the Earnings list. This HashMap only has at most 7 keys as these keys are determined by the name of the days in a week. Inside the HashMap, there are ArrayList mapped as the values of the HashMap. This feature consists of 2 main commands. The first command is weekly_earnings INDEX count/COUNT and the second command is auto. Users have to add the earnings that they want to repeat over the weeks manually first. After they have added the earnings, they can invoke the weekly_earnings command to auto add the earnings for the next few weeks depending on the number of counts they have inputted. The weekly_earnings command add the key-value pair to a HashMap in Earnings class. Once the user invokes the auto command, the parser will check the current day of the week and get the value of the HashMap that is associated with the key value (that is the day of the week). If there exists an ArrayList, the parser will check through the entire list and check if the Earnings in the ArrayList has more than a Count of 0. If the Count is more than zero, then the parser adds the Earnings object into the current list. If the Count is zero, the Earnings object would be removed from the ArrayList.
Minor Enhancement: Register and Login feature.
- What it does: It allows the user to register and login into the application.
- Justification: This feature improves the product significantly because as a Tutor, you would enter in critical and sensitive information of your students and of your earnings. By adding a register and login feature, it makes the app a lot more secure and tutors can confidently enter data into their application worry-free.
- Implementation: This enhancement alters the way TutorAid is used. Normally, users could enter into the application once they launched it. But with the register and login feature, it only allows users to login when they have the correct credentials. The register and login feature is aided by a password encryption method. When users register, the passwords of the accounts created will be hashed with a salt so that there will be more security. I created a Login Window as well so that the users can have a visual cue when they login into their account.
Code contributed: [All commits] [Project Code Dashboard]
Other contributions:
- Project management:
  - Managed and assigned the issues at the start of the project: #82, #94, #104
  - Managed release First Draft, v1.2 and v1.3.2 on Github
  - Ensured the travis build was always working and passed before milestone deadlines. #246, #173
  - Implemented Protected Branches on team repository so as to have teammates review each other and prevent accidental merges.
- Enhancements to existing features:
  - Wrote multiple tests for existing features to increase code coverage incrementally (#386, #345, #337)
- Documentation:
  - Added detailed implementation documentation for the account storage and earnings feature in Developer Guide, including diagrams (#201, #203)
  - Customized and updated ReadMe for TutorAid
- Community:
  - Consistently reviewed and gave feedback to team members. PRs reviewed: #243, #214
- Tools:
  - Set up Netlify
  - Set up Token Generator Account for team repository.

Contributions to the User Guide

Given below are sections I contributed to the User Guide. They showcase my ability to write documentation targeting end-users.

Auto Add Weekly Earnings: `weekly_earnings`

Automates the additon of earnings.
Format: weekly_earnings INDEX count/NUMBER_OF_WEEKS

Figure 2. Weekly Earnings Example

Examples:

weekly_earnings 2 count/2
weekly_earnings 3 count/13

Only numbers in the range of 0 - 13 (inclusive) are valid.
This auto add will only occur on the day itself by invoking auto command.
It is not allowed to add earnings 2 weeks prior and expect the application to add the earnings twice. It will only add on the day itself.
Using this command assumes that all attributes of the indexed earnings are the same for future earnings other than the date.
Recommended Usage: If you have a day with several tutorials and labs that repeat every week, you can use weekly_earnings command to add them into a list. Once inside the list, for the next few weeks, depending on your Count, you can easily add them by invoking the auto command.

Adds Weekly Earnings: `auto`

Adds all the earnings that were invoked by weekly_earnings.
Format: auto

Example:

auto

It must be invoked on the day itself for it to work.
If user has missed a day, the earnings will not be added. For example, if an earnings has a date of 02/02/2019, and the auto command is invoked on the day of 10/02/2019 instead of 09/02/2019, the earnings will not be added.
Suggested to invoked everyday.

Contributions to the Developer Guide

Given below are sections I contributed to the Developer Guide. They showcase my ability to write technical documentation and the technical depth of my contributions to the project.

Add Earnings

The add_earnings command allows for tutors to add their earnings into TutorAid.

The format for the add_earnings command is as follows:

add_earnings d/<DATE> type/<TYPE> c/<CLASSID> amt/<AMOUNT>

Overview

The add_earnings mechanism is facilitated by AddEarningsCommand and AddEarningsCommandParser, taking in the following input from the user: Date, Type, ClassId, Amount, which will construct Earnings objects.

Figure 3. Add Earnings Command Sequence Diagram

The AddEarningsCommand implements Parser with the following operation:

AddEarningsCommandParser#parse() - This operation will take in a String input from the user and create individual objects based on the prefixes d/, c/, type/ and amt/. The String value after the respective prefixes will create the respective objects. A validation check will be done to ensure that the strings that are entered by the user is entered correctly. If any of the strings entered are invalid, an error will be shown to the user to enter the correct format of the respectives objects.
- date would use ParserUtil#parseDate() to ensure that the date typed by the user is in the correct format of DD/MM/YYYY.
- type would use ParserUtil#parseType() to ensure that the type entered by the user is valid.
- classId would use ParserUtil#parseClassId() to ensure that the class id typed in by the user is in the correct format.
- amount would use ParserUtil#parseAmount() to ensure that the amount entered by the user is in the correct format with 2 decimal places to represent the cents.
After validation of the individual objects, an Earnings object would be created with the parameters date, type, classId and amount.
AddEarningsCommandParser would then return a AddEarningsCommand object with the parameter, Earnings object.

Example Scenerio

Step 1: The user enters add_earnings d/04/08/2019 type/tut c/CS1231 amt/50.00 to add an earning for teaching classes. In this example, it adds an Earnings object that the user has earned $50.00 by teaching a CS1231 tutorial class on 4th August 2019.
Step 2: LogicManager would use TutorAidParser#parse() to parse input from the user.
Step 3: TutorAidParser would match the command word given by the user with the correct command. In this example, the given command is add_earnings, thus, AddEarningsCommandParser object would be created with the user’s input.
Step 4: AddEarningsCommandParser performs a validation check on each of the respective objects through AddEarningsCommandParser#parse(). In this case, it would use ParserUtil#parseDate(), ParserUtil#parseType(), ParserUtil#parseClassId() and ParserUtil#parseAmount(). It would then return a AddEarningsCommand object with an Earnings object.
Step 5: LogicManager would execute AddEarningsCommand#execute. In this particular method, the Earnings object will be check with the rest of the prior Earnings object, to ensure that there is no duplicate Earnings object. If there are no similar Earnings object with the same parameters created previously, it would then be added into the earnings list.
Step 6: AddEarningsCommand would then return a CommandResult to LogicManager, which would show the user that the new Earnings object have been successfully added.

Weekly Earnings

The weekly_earnings command allows users to add earnings into a list. This list adds earnings weekly by invoking the auto command automatically. This helps to lessen the workload on the user as the user does not need to add a new earnings every week.

The format for the weekly_earnings command is as follows:

weekly_earnings INDEX count/<NUM_OF_WEEKS>

Overview

The weekly_earnings mechanism is facilitated by AutoAddEarningsCommand and AutoAddEarningsCommandParser, taking in the following input from the user: Index and Count, which would be associated with the Earnings object that is referenced from the Index. The Count object represents the number of weeks the earnings are to be added to the list.

The AutoAddEarningsCommand implements Parser with the following operation:

AutoAddEarningsCommandParser#parse() - This operation will take in an int input from the user, followed by a String input from the user and create individual objects based on the prefix count/. The String value after the prefix will create a Count object. A validation check will be done to ensure that the string that is entered by the user is entered correctly. If the string entered is invalid, an error will be shown to the user to enter the correct format of the Count object.
- index would use ParserUtil#parseIndex() to ensure that the index typed in by the user is in the correct format and is valid.
- count would use ParserUtil#parseCount() to ensure that the count typed by the user is in the correct format and between 0 - 13 (inclusive).
After validation of the individual objects, the particular Earnings object would have a Count object and be added to a list that is ready to be added automatically.
AutoAddEarningsCommandParser would then return a AutoAddEarningsCommand object with the parameters, Index and Count object.

Example Scenerio

Step 1: The user enters weekly_earnings 2 count/3 to add that indexed earnings to a list of earnings to be added on the same day of the week, every week. For example, if the referenced earnings has a date of 01/11/2019, which is a Friday, that particular earnings will be added on every Friday for a total of 3 weeks.
Step 2: LogicManager would use TutorAidParser#parse() to parse input from the user.
Step 3: TutorAidParser would match the command word given by the user with the correct command. In this example, the given command is weekly_earnings, thus, AutoAddEarningsCommandParser object would be created with the user’s input.
Step 4: AutoAddEarningsCommandParser performs a validation check on each of the respective objects through AutoAddEarningsCommandParser#parse(). In this case, it would use ParserUtil#parseIndex() and ParserUtil#parseCount(). It would then return a AutoAddEarningsCommand object with an Index and Count objects.
Step 5: LogicManager would execute AutoAddEarningsCommand#execute. In this particular method, the Earnings object will be check with the rest of the prior Earnings object that has been added to the auto addition of earnings list, to ensure that there is no duplicate Earnings object in the list. If there are no similar Earnings object with the same parameters created previously, it would then be added into the auto addition earnings list.
Step 6: AutoAddEarningsCommand would then return a CommandResult to LogicManager, which would show the user that the new Earnings object have been successfully added to the list.

Auto Add

This command, auto, allows the user to add all the earnings that has been previously added before and the command weekly_earnings has been used on the particular earnings. You can refer to the activity diagram below to have a clearer understanding.

Figure 4. Auto Command Activity Diagram

Overview The auto command is facilitated by AutoCommand.

AutoCommand#execute - This operation checks the current day of the week and checks against the HashMap of the earnings list. If there are Earnings object associated with the current day of the week and the Earnings object has a Count object associated with it that is more than 1. The earnings inside the ArrayList inside the HashMap would be added into the earnings list.

Example Scenario

Step 1: The user enters auto to add all his days earnings into the earnings list.
Step 2: LogicManager would use TutorAidParser#parse() to parse input from the user.
Step 3: TutorAidParser would match the command word given by the user with the correct command. In this example, the given command is auto, thus, AutoCommand object would be created with the user’s input.
Step 4: LogicManager would execute AutoCommand#execute. In this particular method, the execute command would check the day of the week. It would then check with the HashMap to check if there is any ArrayList of Earnings object to be added in. If there is no ArrayList available, no earnings would be added. If there is an ArrayList mapped to the day of the week, the method would then check through every Earnings object in the ArrayList. In each Earnings object, there is a Count object associated to it. If the Count object has a more than 1, the Earnings object would be added into the current earnings list. If the Count object has a value of 0, the Earnings object would be removed from the ArrayList.
Step 6: AutoCommand would then return a CommandResult to LogicManager, which would show the user that the new Earnings object have been successfully added to the list.

Account Storage

All accounts are stored in a JSON file called accountslist.json. This file is generated once you register an account. The username and password is stored inside the the JSON file with salt hashing thus, the account details cannot be seen by everyone.

Design Considerations We realised that storing the accounts by itself would allow anyone to see the username and passwords. Hence, we decided to use a password authentication method and salt hashing to cover the passwords of the accounts.

In addition, we decided to go with using a JSON file instead of XML file due to these considerations:

Table 1. Account File Storage function alternatives
Design Consideration	Pros and Cons
XML File	Pros : Easy transfer of data between seperate systems. Good at storing data that will be readby 3rd parties. Cons : Not familiar with it and we would require more time to learn how to use it.
JSON File (Current Choice)	Pros : More familiarity with JSON files. More compact and can be easily loaded. Flexible Cons : Bad Schema support and namespace support

Security Considerations As of now, only password hashing is done to protect the accounts from being seen by unwanted eyes. We have planned ahead of time and decided to implement better security options for v2.0.

Store accounts on a backend server: The project restricts us and as of now, it is not implemented. The advantages of storing the accounts in database is that it can be a lot more secure.
Encrypt the Account JSON file: This will prevent other users from easily clicking into the data file and make it more secure.