Developer Guide

Table of Contents

• Acknowledgements
• Setting up, getting started
• Design
  • Architecture
  • UI component
  • Logic component
  • Model component
  • Storage component
  • Common classes
• Implementation
  • Add feature
  • Save feature
  • [Proposed] Undo/redo feature
• Documentation, logging, testing, configuration, dev-ops
• Appendix: Requirements
  • Product scope
  • User stories
  • Use cases
  • Non-Functional Requirements
  • Glossary
• Appendix: Instructions for manual testing

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Acknowledgements

• This project is based on the AddressBook-Level3 project created by the SE-EDU initiative. If you would like to contribute code to this project, see se-education.org for more info. Refer here for source code.

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Setting up, getting started

Refer to the guide Setting up and getting started.

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Design

Architecture

The Architecture Diagram given above explains the high-level design of the App.

Given below is a quick overview of main components and how they interact with each other.

Main components of the architecture

Main (consisting of classes Main and MainApp) is in charge of the app launch and shut down.

• At app launch, it initializes the other components in the correct sequence, and connects them up with each other.
• At shut down, it shuts down the other components and invokes cleanup methods where necessary.

The bulk of the app’s work is done by the following four components:

• UI: The UI of the App.
• Logic: The command executor.
• Model: Holds the data of the App in memory.
• Storage: Reads data from, and writes data to, the hard disk.

Commons represents a collection of classes used by multiple other components.

How the architecture components interact with each other

The Sequence Diagram below shows how the components interact with each other for the scenario where the user issues the command delete 1.

Each of the four main components (also shown in the diagram above),

• defines its API in an interface with the same name as the Component.
• implements its functionality using a concrete {Component Name}Manager class (which follows the corresponding API interface mentioned in the previous point.

For example, the Logic component defines its API in the Logic.java interface and implements its functionality using the LogicManager.java class which follows the Logic interface. Other components interact with a given component through its interface rather than the concrete class (reason: to prevent outside component’s being coupled to the implementation of a component), as illustrated in the (partial) class diagram below.

The sections below give more details of each component.

UI component

The API of this component is specified in Ui.java

The UI consists of a MainWindow that is made up of parts e.g.CommandBox, ResultDisplay, PersonListPanel, StatusBarFooter etc. All these, including the MainWindow, inherit from the abstract UiPart class which captures the commonalities between classes that represent parts of the visible GUI.

The UI component uses the JavaFx UI framework. The layout of these UI parts are defined in matching .fxml files that are in the src/main/resources/view folder. For example, the layout of the MainWindow is specified in MainWindow.fxml

The UI component,

• executes user commands using the Logic component.
• listens for changes to Model data so that the UI can be updated with the modified data.
• keeps a reference to the Logic component, because the UI relies on the Logic to execute commands.
• depends on some classes in the Model component, as it displays Person, Student and Parent objects residing in
• the Model.

Logic component

API : Logic.java

Here’s a (partial) class diagram of the Logic component:

The sequence diagram below illustrates the interactions within the Logic component, taking execute("delete 1") API call as an example.

How the Logic component works:

1. When Logic is called upon to execute a command, it is passed to an AddressBookParser object which in turn creates a parser that matches the command (e.g., DeleteCommandParser) and uses it to parse the command.
2. This results in a Command object (more precisely, an object of one of its subclasses e.g., DeleteCommand) which is executed by the LogicManager.
3. The command can communicate with the Model when it is executed (e.g. to delete a person).
   Note that although this is shown as a single step in the diagram above (for simplicity), in the code it can take several interactions (between the command object and the Model) to achieve.
4. The result of the command execution is encapsulated as a CommandResult object which is returned back from Logic.

Here are the other classes in Logic (omitted from the class diagram above) that are used for parsing a user command:

How the parsing works:

• When called upon to parse a user command, the AddressBookParser class creates an XYZCommandParser (XYZ is a placeholder for the specific command name e.g., AddCommandParser) which uses the other classes shown above to parse the user command and create a XYZCommand object (e.g., AddCommand) which the AddressBookParser returns back as a Command object.
• All XYZCommandParser classes (e.g., AddCommandParser, DeleteCommandParser, …) inherit from the Parser interface so that they can be treated similarly where possible e.g, during testing.

Model component

API : Model.java

The Model component,

• stores the address book data i.e., all Person objects (which are contained in a UniquePersonList object), and all Reminder objects.
• stores the currently ‘selected’ Person objects (e.g., results of a search query) as a separate filtered list which is exposed to outsiders as an unmodifiable ObservableList<Person> that can be ‘observed’ e.g. the UI can be bound to this list so that the UI automatically updates when the data in the list change.
• Student and Parent objects both inherit from Person class.
• stores a UserPref object that represents the user’s preferences. This is exposed to the outside as a ReadOnlyUserPref objects.
• does not depend on any of the other three components (as the Model represents data entities of the domain, they should make sense on their own without depending on other components)

Storage component

API : Storage.java

The Storage component,

• can save both address book data and user preference data in JSON format, and read them back into corresponding objects.
• inherits from both AddressBookStorage and UserPrefStorage, which means it can be treated as either one (if only the functionality of only one is needed).
• depends on some classes in the Model component (because the Storage component’s job is to save/retrieve objects that belong to the Model)

Common classes

Classes used by multiple components are in the tutorpro.commons package.

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Implementation

This section describes some noteworthy details on how certain features are implemented.

Add feature

Current implementation

The revised add mechanism is facilitated by Student. It extends Person and contains the following additional fields compared to the original version from AB3.

• Level - Representing the education level
• Subject - Representing a subject, as well as its corresponding grade

As compared to Person, instances of Student will automatically have a “Student” Tag added on construction.

Otherwise, all other implementation details are the same as AB3.

Save feature

Current implementation

The revised save mechanism is facilitated by JsonSerializableAddressBook, that directly or indirectly contains various other classes that convert objects to be saved to Jackson-friendly versions, heavily inspired by the original AB3 code.

• JsonAdaptedStudent for the Student class
• JsonAdaptedSubject for the Subject class
• JsonAdaptedParent for the Parent class
• JsonAdaptedReminder for the Reminder class
• JsonAdaptedEvent for the Event class

When saving, a new JsonSerializableAddressBook object is created, with a ReadOnlyAddressBook as a parameter. All Persons and child classes are retrieved from the ReadOnlyAddressBook as a stream, then split using filter to create their respective Jackson-friendly versions. The same as done for all Reminders and child classes.

Loading is implemented in the same way as AB3.

[Proposed] Undo/redo feature

Proposed Implementation

The proposed undo/redo mechanism is facilitated by VersionedAddressBook. It extends AddressBook with an undo/redo history, stored internally as an addressBookStateList and currentStatePointer. Additionally, it implements the following operations:

• VersionedAddressBook#commit() — Saves the current address book state in its history.
• VersionedAddressBook#undo() — Restores the previous address book state from its history.
• VersionedAddressBook#redo() — Restores a previously undone address book state from its history.

These operations are exposed in the Model interface as Model#commitAddressBook(), Model#undoAddressBook() and Model#redoAddressBook() respectively.

Given below is an example usage scenario and how the undo/redo mechanism behaves at each step.

Step 1. The user launches the application for the first time. The VersionedAddressBook will be initialized with the initial address book state, and the currentStatePointer pointing to that single address book state.

Step 2. The user executes delete 5 command to delete the 5th person in the address book. The delete command calls Model#commitAddressBook(), causing the modified state of the address book after the delete 5 command executes to be saved in the addressBookStateList, and the currentStatePointer is shifted to the newly inserted address book state.

Step 3. The user executes add n/David …​ to add a new person. The add command also calls Model#commitAddressBook(), causing another modified address book state to be saved into the addressBookStateList.

Step 4. The user now decides that adding the person was a mistake, and decides to undo that action by executing the undo command. The undo command will call Model#undoAddressBook(), which will shift the currentStatePointer once to the left, pointing it to the previous address book state, and restores the address book to that state.

The following sequence diagram shows how an undo operation goes through the Logic component:

Similarly, how an undo operation goes through the Model component is shown below:

The redo command does the opposite — it calls Model#redoAddressBook(), which shifts the currentStatePointer once to the right, pointing to the previously undone state, and restores the address book to that state.

Step 5. The user then decides to execute the command list. Commands that do not modify the address book, such as list, will usually not call Model#commitAddressBook(), Model#undoAddressBook() or Model#redoAddressBook(). Thus, the addressBookStateList remains unchanged.

Step 6. The user executes clear, which calls Model#commitAddressBook(). Since the currentStatePointer is not pointing at the end of the addressBookStateList, all address book states after the currentStatePointer will be purged. Reason: It no longer makes sense to redo the add n/David …​ command. This is the behavior that most modern desktop applications follow.

The following activity diagram summarizes what happens when a user executes a new command:

Design considerations:

Aspect: How undo & redo executes:

• Alternative 1 (current choice): Saves the entire address book.

  • Pros: Easy to implement.
  • Cons: May have performance issues in terms of memory usage.

• Alternative 2: Individual command knows how to undo/redo by itself.

  • Pros: Will use less memory (e.g. for delete, just save the person being deleted).
  • Cons: We must ensure that the implementation of each individual command are correct.

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Documentation, logging, testing, configuration, dev-ops

• Documentation guide
• Testing guide
• Logging guide
• Configuration guide
• DevOps guide

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Appendix: Requirements

Product scope

Target user profile:

• Private tutors who prefer CLI over GUI
• Private tutors who go to tutees’ houses and teach one-to-one
• Private tutors who teach multiple subjects
• Private tutors who teach multiple levels or a specific level, e.g. primary school students
• Private tutors who need to track the progress of each student e.g. grades
• Private tutors who need to keep track of lesson plans
• Private tutors who need to manage their schedule
• Private tutors who need to manage a list of student contacts
• Private tutors who need to manage a list of parent contacts

Value proposition: Allows for easy track and management of tutees, e.g. grades, addresses, contacts

User stories

Priorities: High (must have) - * * *, Medium (nice to have) - * *, Low (unlikely to have) - *

Priority	As a …​	I want to …​	So that I can…​
* * *	private tutor	track my tutee’s grades, addresses and contacts easily	efficiently manage my tutoring sessions
* * *	private tutor	input new tutees’ progress seamlessly	add new tutees’ information
* * *	private tutor	delete previously created inputs	remove information that I no longer need
* * *	private tutor	track my project tasks and timelines seamlessly	effectively manage my workflow and deliver on time
* *	private tutor	set reminders for important deadlines and milestones	never miss a crucial event

Use cases

(For all use cases below, the System is TutorPro and the Actor is the user, unless specified otherwise)

Use case: Add a student

MSS

1. The user requests to add a specific student

2. TutorPro adds the student

   Use case ends.

Extensions

• 2a. The student has the same details as someone already in the list.

  • 2a1. TutorPro shows an error message.

    Use case ends.

Use case: Delete a student

MSS

1. The user requests to list students
2. TutorPro shows a list of students
3. User requests to delete a specific student in the list

4. TutorPro deletes the student

   Use case ends.

Extensions

• 2a. The list is empty.

  Use case ends.

• 3a. The given index is invalid.

  • 3a1. TutorPro shows an error message.

  Use case resumes at step 2.

• 3b. The given student does not exist in the list.

  • 3b1. TutorPro displays an error message.

  Use case resumes at step 2.

Use case: Find a student

MSS

1. The user requests to find a specific student.

2. TutorPro displays a list of students whose details match the user input.

   Use case ends.

Extensions

• 2a. The specified student does not exist in the list.

  • 2a1. TutorPro shows an error message.

    Use case ends.

Use case: Update a student’s progress/particulars

MSS

1. The user requests to update a specific student’s progress/particulars.
2. TutorPro updates the student’s progress/particulars.

3. TutorPro displays the updated information to the user for verification.

   Use case ends.

Extensions

• 2a. The specified student does not exist in the list.

  • 2a1. TutorPro shows an error message.

    Use case ends.

• 2b. The given category is not one of the available categories.

  • 2b1. TutorPro shows an error message.

    Use case ends.

• 2c. Given new information to update does not match the input format for the particular category.

  • 2c1. TutorPro shows an error message.

    Use case ends.

Use case: Setting a reminder

MSS

1. The user requests to set a reminder.
2. TutorPro sets the reminder.

3. TutorPro displays a list of currently scheduled reminders.

   Use case ends.

Extensions

• 2a. The given date or time is in an incorrect format.

  • 2a1. TutorPro shows an error message.

    Use case ends.

Use case: Create a tag

MSS

1. The user requests to create a tag.
2. TutorPro creates the specified tag.

3. TutorPro displays a list of created tags.

   Use case ends.

Extensions

• 2a. The specified tag to create already exists.

  • 2a1. TutorPro shows an error message.

    Use case ends.

Use case: Tag a student

MSS

1. The user requests to tag a student.
2. TutorPro tags the student.

3. TutorPro displays the list of students who have the same tag.

   Use case ends.

Extensions

• 2a. The specified student does not exist in the list.

  • 2a1. TutorPro displays an error message.

    Use case ends.

• 2b. The specified tag does not exist.

  • 2b1. TutorPro displays an error message.

    Use case ends.

Use case: Display the user’s schedule

MSS

1. The user requests to display their current schedule.

2. TutorPro displays the user’s current schedule

   Use case ends.

Extensions

• 2a. The user has nothing in their schedule.

  • 2a1. TutorPro shows an error message.

    Use case ends.

Use case: Set a recurring event

MSS

1. The user requests to set an event that recurs weekly.
2. TutorPro sets the event.

3. TutorPro displays the list of the user’s weekly recurring events.

   Use case ends.

Extensions

• 2a. Given day(s) is/are in the wrong input format.

  • 2a1. TutorPro shows an error message.

    Use case ends.

• 2b. Given student does not exist in the list.

  • 2b1. TutorPro shows an error message.

    Use case ends.

Non-Functional Requirements

1. Security:

• The application must ensure secure storage and transmission of sensitive student data, such as grades and contact information, adhering to industry-standard encryption protocols.
• Access to student records must be restricted to authorized users only, with role-based access control mechanisms in place.

1. Privacy:

• The application should comply with relevant privacy regulations (e.g., GDPR, HIPAA) to safeguard students’ personal information.
• Student data should only be accessible to the student, their assigned tutor, and authorized administrative staff.

1. Scalability:

• The system must be able to handle a growing number of students and tutors without a significant decrease in performance.
• It should support concurrent access by multiple users without degradation in response time or system stability.

1. Reliability:

• The application should have minimal downtime and be available for use during critical academic periods, such as exam periods or assignment deadlines.
• It should have mechanisms in place to recover from failures gracefully, ensuring data integrity and continuity of service.

1. Interoperability:

• The application should be compatible with various devices and operating systems commonly used by both tutors and students, such as laptops, tablets, and smartphones.
• It should support integration with other academic systems or tools, such as learning management systems or scheduling software.

1. Usability:

• The application interface should be intuitive and user-friendly, requiring minimal training for tutors and students to navigate and use effectively.
• It should provide clear instructions and guidance for inputting and accessing academic information and contact details.

1. Performance:

• The system should respond promptly to user actions, such as loading student profiles, updating grades, or scheduling tutoring sessions, aiming for sub-second response times.
• It should efficiently manage database queries and data retrieval to prevent delays in accessing information.

1. Maintainability:

• The application codebase should be well-documented and modular, facilitating ease of maintenance and future enhancements.
• It should support version control and have mechanisms for bug tracking and resolution.

1. Accessibility:

• The application interface should be accessible to users with disabilities, following web accessibility guidelines such as WCAG.
• It should support alternative input methods, screen readers, and keyboard navigation for users with visual or motor impairments.

1. Backup and Disaster Recovery:

• Regular backups of student data should be performed, with procedures in place for data restoration in case of accidental deletion or system failure.
• The application should have disaster recovery measures to ensure minimal data loss and service disruption in the event of server or infrastructure failures.

Glossary

• Encryption - The process of converting information or data into a code, especially to prevent unauthorized access.
• Data integrity - The accuracy, completeness, and quality of data as it’s maintained over time and across formats.
• Operating system - Mainstream operating systems are: Windows, Linux, Unix, MacOS
• Modular - By modularizing a codebase you will define more clear boundaries between different clusters of objects that make up a screen of feature.

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Appendix: Instructions for manual testing

Given below are instructions to test the app manually.

Launch and shutdown

1. Initial launch

   1. Download the jar file and copy into an empty folder

   2. Double-click the jar file Expected: Shows the GUI with a set of sample contacts. The window size may not be optimum.

2. Saving window preferences

   1. Resize the window to an optimum size. Move the window to a different location. Close the window.

   2. Re-launch the app by double-clicking the jar file.
      Expected: The most recent window size and location is retained.

Deleting a person

1. Deleting a person while all persons are being shown

   1. Prerequisites: List all persons using the list command. Multiple persons in the list.

   2. Test case: delete 1
      Expected: First contact is deleted from the list. Details of the deleted contact shown in the status message. Timestamp in the status bar is updated.

   3. Test case: delete 0
      Expected: No person is deleted. Error details shown in the status message. Status bar remains the same.

   4. Other incorrect delete commands to try: delete, delete x, ... (where x is larger than the list size)
      Expected: Similar to previous.