Developer Guide

Table of Contents

Acknowledgements
Setting up, getting started
Design
Implementation
Documentation, logging, testing, configuration, dev-ops
Appendix: Requirements
Appendix: Instructions for manual testing
1. Launch and shutdown
2. Deleting a person
Appendix: Planned Enhancements

Acknowledgements

GoonBook is a brownfield software project based off AddressBook Level-3 (UG, DG), taken under the CS2103T Software Engineering module held by the School of Computing at the National University of Singapore.

Java dependencies:

JavaFX for GUI
JUnit5 for testing

Documentation dependencies:

Jekyll for rendering the website
PlantUML for creating UML diagrams

Setting up, getting started

Refer to the guide Setting up and getting started.

Design

Tip: The .puml files used to create diagrams in this document docs/diagrams folder. Refer to the PlantUML Tutorial at se-edu/guides to learn how to create and edit diagrams.

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

Structure of the UI Component

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 object and Group object 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.

Interactions Inside the Logic Component for the `delete 1` Command

Note: The lifeline for DeleteCommandParser should end at the destroy marker (X) but due to a limitation of PlantUML, the lifeline continues till the end of diagram.

How the Logic component works:

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.
This results in a Command object (more precisely, an object of one of its subclasses e.g., DeleteCommand) which is executed by the LogicManager.
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.
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).
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.
stores the currently ‘selected’ Group objects (e.g., results of a search query) as a separate filtered list which is exposed to outsiders as an unmodifiable ObservableList<Group> 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.
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)

Note: An alternative (arguably, a more OOP) model is given below. It has a Tag list in the AddressBook, which Person references. This allows AddressBook to only require one Tag object per unique tag, instead of each Person needing their own Tag objects.

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 seedu.address.commons package.

Implementation

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

Group feature

The GroupCommand allows educators to group students together within the application. This is particularly useful for managing classes, group-based activities, assignments, and projects efficiently.

Implementation Details

The GroupCommand is implemented by extending the base Command class. It uses prefixes such as /g, /s, specifying required data fields groupName, students, respectively. Once the data fields are filled, a new Group is added. It implements the following operations:

execute(Model) — Checks the current address book state by calling the following methods as part of our defensive programming:
1. model.hasGroupName(new Group(groupName, List.of())), and throws a CommandException if a duplicate Group is found
2. groupName.isEmpty(), and throws a CommandException if a the group name field is empty is found
3. model.getFilteredPersonList(), to obtain a List<Person> to iterate over to search for the inputted student names and adding them to a new List<Person> to be passed into the constrcutor for a new Group
addGroup(group) — Adds the Group to the group list. This operation is exposed in the Model interface as Model#addGroup(Group).

The Group command is initiated by firstly checking the filtered group list to ensure no duplicate is found, after which Model#addGroup(Group) is called to complete the actual addition.

Given below is an example usage scenario of how the addition mechanism behaves when the user tries to add a group to the group list.

Step 1. The user launches the application, with some students and groups added to the address book already. The AddressBook will be initialized with the previously saved address book state.

Step 2. The user executes group command with the specific data at each prefix to specify the person to be added. The GroupCommand will then call excecute(), which checks whether there is a duplicate Group in the group list before calling addGroup(Group).

Note: If the groupName and students provided is invalid, a CommandException will be thrown.

Sequence Diagram

Design considerations:

Aspect: How Group executes:

Alternative 1 (current choice): Create a new Group Object containing a list of Person, and storing it in the model component.
- Pros: Easier to implement and more intuitive.
- Cons: May have performance issues in terms of memory usage, and deleting a student will require iterating over all Groups to ensure it is deleted from all groups
Alternative 2: Each Person Object has a field of a List of all the groups it is in.
- Pros: Deleting a person is alot easier (Simply by deleting the Person Object will remove it from all the Groups it is in)).
- Cons: Very hard to implement, and not a good representation of the has-a relationship between Group and Person.

Delete Group feature

The DeleteGroupCommand allows educators to delete Groups within the application. This is particularly useful for deleting Groups that the user no longer need, assisting the management of Groups.

Implementation Details

The DeleteGroupCommand is implemented by extending the base Command class. It does not use any prefixes, rather using the groupName to identify which group to delete. Once the data fields are filled, it will look for the specified group containing that groupName and delete it. It implements the following operations:

execute(Model) — Checks the current address book state by calling the model.getFilteredGroupList() to obtain an ObservableList<Group> and iterating over it to find a matching groupName, throwing a CommandException if no Group is found.
deleteGroup(groupToDelete) — Deletes the Group from the group list. This operation is exposed in the Model interface as Model#deleteGroup(Group).

Given below is an example usage scenario of how the delete group mechanism behaves when the user tries to delete a group from the group list.

Step 1. The user launches the application, with some students and groups added to the address book already. The AddressBook will be initialized with the previously saved address book state.

Step 2. The user executes deleteGroup command with the specified Group Name to specify the Group to be added. The deleteGroupCommand will then call excecute(), which checks whether there is a Group in the group list that matches the name before calling deleteGroup(Group).

Sequence Diagram

Design considerations:

Aspect: How deleteGroup executes:

Alternative 1 (current choice): Iterating over all Group in model and searching for a match and proceeding to delete that group
- Pros: Easier to implement, and deleting a Group will not cause bugs in other logic components
- Cons: Can become very slow when there are many groups in Logic
Alternative 2: Using a Hash to map every groupName to its respective Group
- Pros: Deleting a Group is much faster, since there is no longer a need to iterate over all groups within model
- Cons: The logic will be much more complicated, and showing a Hash through JavaFx is much more difficult compared to using the already provided ObservableList

Export feature

The ExportCommand allows educators to export the data in their current GoonBook storage out as a csv file for usage in other spreadsheets such as Google spreadsheets, giving GoonBook seamless integration with existing spreadsheet editors.

Implementation Details

The ExportCommand is implemented by extending the base Command class. It does not use any prefixes, and is called as is. Once the data fields, like projectRootPath are filled, it will proceed to convert the data in model into a json file, then into a csv file for the user to freely use. It implements the following operations:

execute(Model) — Obtain the Path Objects that represent both the import directory, and the export directory, by calling the Path#resolve method.
saveJsonfile — Takes in the model, importPath and exportPath as parameters to then convert the data in model to a csv file by further calling the methods translateJsonToCsv and getPersonTags which will perform the necessary actions to convert the json file into a csv file

Given below is an example usage scenario of how the export mechanism behaves when the user tries to export data from GoonBook.

Step 1. The user launches the application, with some students and groups added to the address book already. The AddressBook will be initialized with the previously saved address book state.

Step 2. The user executes export command. The ExportCommand will then call excecute(), which proceeds to take the current data stored in the address book and converting it into a csv file, and saving it in the same directory as root for the user to access

Sequence Diagram

Design considerations:

Aspect: How export executes:

Alternative 1 (current choice): Using the existing Storage interface and addressBook.json to directly convert into a csv file
- Pros: Has already laid the foundation for our csv conversion method to build off from
- Cons: Has an added dependency on the json file, so if any issues were to occur to the json coverter, it would mean that the export function would no longer function
Alternative 2: Directly exporting the data of the address book and converting it into a csv file without needing the dependency on the json file
- Pros: Will ensure that any bugs with the jsonAdaptablePersons and etc will not affect the functionality of the export function, since they would no longer be associated
- Cons: Extremely hard to implement, and would not be worth the hassle

Tag feature

The TagCommand allows educators to add custom tags to their students for quality of life benefits, such as reminders, or to categorise them accordingly.

Implementation Details

The TagCommand is implemented by extending the base Command class. It uses only the prefix /t taking in a index as the other part of the command syntax, specifying required data fields newTags and targetIndex, respectively. Once the data fields are filled, new tags are added to a specified Person. It implements the following operations:

execute(Model) — Obtain a List<Person> using the model.getFilteredPersonList, and using the targetIndex to get the corresponding Person object to add the newTags to, by calling model.addTag
targetIndex.getZeroBased — Used to check if the given index is larger than the size of the filteredPersonList, and throws a CommandException if the index is larger than the index in filteredPersonList
model.tagExists(person, newTags) — Used to check if the person object already has the given tag name already, throws a CommandException if the person is found to already have an existing tag of the same name

Given below is an example usage scenario of how the tag mechanism behaves when the user tries to add a tag to a student

Step 1. The user launches the application, with some students and groups added to the address book already. The AddressBook will be initialized with the previously saved address book state.

Step 2. The user executes tag command. The TagCommand will then call excecute(), which proceeds to take the list of filtered person, and using the index provided by the user, choose that specific person to add the given tags to

Sequence Diagram

Design considerations:

Aspect: How tag executes:

Alternative 1 (current choice): Using a Set to implement a collection of tags per student
- Pros: Can easily check to see if there are any duplicate tags due to the nature of the data structure, saving time that would have otherwise been spent iterating through it
- Cons: If we ever decided to allow multiple tags with the same name, we will not be able to do so
Alternative 2: Using a List to implement a collection of Tags
- Pros: Much simpler to implement, and familiar to use
- Cons: Can become very inefficient, when there are many tags, it could take some time to iterate through every tag one by one to ensure that the same tag doesn’t exist twice

[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.

UndoRedoState0

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.

UndoRedoState1

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.

UndoRedoState2

Note: If a command fails its execution, it will not call Model#commitAddressBook(), so the address book state will not 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.

UndoRedoState3

Note: If the currentStatePointer is at index 0, pointing to the initial AddressBook state, then there are no previous AddressBook states to restore. The undo command uses Model#canUndoAddressBook() to check if this is the case. If so, it will return an error to the user rather than attempting to perform the undo.

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

UndoSequenceDiagram

Note: The lifeline for UndoCommand should end at the destroy marker (X) but due to a limitation of PlantUML, the lifeline reaches the end of diagram.

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

UndoSequenceDiagram

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.

Note: If the currentStatePointer is at index addressBookStateList.size() - 1, pointing to the latest address book state, then there are no undone AddressBook states to restore. The redo command uses Model#canRedoAddressBook() to check if this is the case. If so, it will return an error to the user rather than attempting to perform the redo.

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.

UndoRedoState4

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.

UndoRedoState5

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.

Documentation, logging, testing, configuration, dev-ops

Appendix: Requirements

Product scope

Target user profile:

educators who need to micromanage multiple students
prefer desktop apps over other types
can type fast
prefers typing to mouse interactions
is reasonably comfortable using CLI apps

Value proposition: Goon Book is specialised to help educators with keeping track of their students. It can be used to record their students with their details, and access relevant information easily and conveniently

User Stories

Priority	As a …	I want to …	So that I can…
`* * *`	educator	add a new student	include all students I have currently in my app
`* * *`	educator	delete a student	keep my database of students concise with only currently relevant students
`* * *`	educator	search for students by name	find information about specific students
`* * *`	educator	group students	efficiently manage classes, group-based activities, assignments, and projects
`* * *`	educator	delete groups	correct mistakes by deleting a group
`* * *`	educator	import and export student data from other systems	streamline data management and avoid manual entry, ensuring compatibility with school databases or grade books
`* *`	educator	search for groups by name	find information about specific groups of students
`* *`	educator	store additional information about students on grades, attendance or notes	better access and organise student information
`* *`	educator	edit a student’s details	correct mistakes or update new information about the student
`* *`	educator	filter searched students by name	quickly find specific students
`*`	educator	use security measures for student data	protect sensitive information and control access to parental data

Use cases

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