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default.md	Developer Guide	3

AB-3 Developer Guide

Acknowledgements

{ list here sources of all reused/adapted ideas, code, documentation, and third-party libraries -- include links to the original source as well }

Setting up, getting started

Refer to the guide Setting up and getting started.

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 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.

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 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.

[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.

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.

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:

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:

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.

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.

{more aspects and alternatives to be added}

[Proposed] Data archiving

{Explain here how the data archiving feature will be implemented}

Documentation, logging, testing, configuration, dev-ops

Appendix: Requirements

Product scope

Target user profile:

Tech meetup organizers managing small-to-medium events (20–150 participants) in Singapore
Manages multiple events per month with varying participant lists
Needs to perform live check-ins and track real-time attendance during events
Prefers desktop applications for stability and offline capability during events
Types fast and prefers keyboard shortcuts over mouse navigation
Comfortable with command-line interfaces and text-based input
Requires instant filtering and searching capabilities (by RSVP, attendance, team, dietary needs)
Manages hackathon team assignments and participant skill tracking
Values data accuracy and quick error correction during live events

Value proposition:

Enable tech event organizers to manage participants. Optimized for live event scenarios with keyboard-first commands for rapid check-ins, instant search, real-time filtering, and on-the-spot team assignments—all without requiring an internet connection.

User stories

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

Priority	As a …	I want to …	So that I can…
`* * *`	new user	see usage instructions and command examples	learn the app quickly and refer back when needed
`* * *`	meetup organizer	add a participant with name, contact, GitHub username, and RSVP status	build my participant list rapidly before events
`* * *`	meetup organizer	edit participant details using quick commands	fix typos or update information instantly during registration
`* * *`	meetup organizer	delete a participant	remove cancellations, duplicates, or test entries
`* * *`	meetup organizer	search participants by name, email, or GitHub username	locate specific attendees in seconds during events
`* * *`	entrance desk organizer	mark a participant as checked-in with one command	process arrivals quickly without slowing the entry queue
`* * *`	meetup organizer	list all participants with a single command	get a complete overview after filtering or searching
`* * *`	meetup organizer	undo my last action	quickly recover from accidental deletions or edits
`* *`	hackathon organizer	assign participants to teams	organize team-based events efficiently
`* *`	meetup organizer	filter participants by RSVP status (Yes/No/Pending)	know exactly who's confirmed and follow up with pending responses
`* *`	meetup organizer	filter participants by check-in status	identify no-shows and track actual attendance vs RSVPs
`* *`	hackathon organizer	filter participants by team assignment	view and manage team rosters quickly
`* *`	meetup organizer with catering responsibilities	filter participants by dietary requirements	ensure accurate meal planning and allergen management
`* *`	meetup organizer	tag participants with custom labels	categorize attendees (e.g., speaker, volunteer, VIP)
`* *`	frequent organizer	import participant lists from CSV files	migrate data from previous tools quickly
`* *`	frequent organizer	export participant data to CSV	share reports with co-organizers or sponsors
`*`	meetup organizer	view attendance statistics and RSVP conversion rates	analyze event turnout and improve future planning
`*`	hackathon organizer	automatically balance teams by declared skills	create fair teams without manual sorting
`*`	meetup organizer	see a timeline of recent actions	track what changes were made during busy check-in periods
`*`	meetup organizer with accessibility needs	use keyboard shortcuts for all operations	manage events efficiently without relying on mouse input

{More to be added}

Use cases

Use Case: UC01 - Check-in a participant

System: TeamEventPro Actor: Organizer

MSS(Main Success Scenario):

Organizer requests to find participants using a keyword.
TeamEventPro shows a list of matching participants.
Organizer requests to check-in a specific participant from the list using their index.
TeamEventPro updates the attendance status of the participant to "checked-in" and shows a success message.

Use case ends.

Extensions

2a. The list of matching participants is empty.
- 2a1. TeamEventPro shows a message indicating no participants were found.
  
  Use case ends.
3a. The given index is invalid.
- 3a1. TeamEventPro shows an error message indicating the index is invalid.
  
  3a2. Organizer enters a new check-in command with a valid index.
  
  Steps resume from step 4.

Use Case: UC02 - Assign a participant to a team

System: TeamEventPro Actor: Organizer

MSS(Main Success Scenario):

Organizer requests to find participants using a keyword.
TeamEventPro shows a list of matching participants.
Organizer requests to assign a specific participant from the list to a team using their index and the team name.
TeamEventPro updates the participant's team affiliation and shows a success message.

Use case ends.

Extensions

2a. The list of matching participants is empty.
- 2a1. TeamEventPro shows a message indicating no participants were found.
  
  Use case ends.
3a. The given index is invalid.
- 3a1. TeamEventPro shows an error message indicating the index is invalid.
  
  3a2. Organizer enters a new team assignment command with a valid index.
  
  Steps resume from step 4.
3b. The given team name format is invalid (e.g., contains special characters).
- 3b1. TeamEventPro shows an error message detailing the team name constraints.
  
  3b2. Organizer enters a new team assignment command with a valid team name.
  
  Steps resume from step 4.

Use Case: UC03 - Delete a participant

System: TeamEventPro Actor: Organizer

MSS(Main Success Scenario):

Organizer requests to find participants using a keyword.
TeamEventPro shows a list of matching participants.
Organizer requests to delete a specific participant from the list using their index.
TeamEventPro deletes the participant and shows a success message.

Use case ends.

Extensions

2a. The list of matching participants is empty.
- 2a1. TeamEventPro shows a message indicating no participants were found.
  
  Use case ends.
3a. The given index is invalid.
- 3a1. TeamEventPro shows an error message indicating the index is invalid.
  
  3a2. Organizer enters a new new delete command with a valid index.
  
  Steps resume from step 4.

{More to be added}

Non-Functional Requirements

Should work on any mainstream OS as long as it has Java 17 or above installed.
Should be able to hold up to 1000 persons without a noticeable sluggishness in performance for typical usage.
A user with above average typing speed for regular English text (i.e. not code, not system admin commands) should be able to accomplish most of the tasks faster using commands than using the mouse.
Any data entered should be saved locally to a human-readable text file automatically after every valid command execution.
The system should provide clear, user-friendly error messages when invalid command formats are entered instead of terminating or crashing.
The system should respond to any search or filtering command within 500 milliseconds even when the database is at maximum capacity (1000 persons).
The software should be delivered as a single JAR file that does not require an installer.
The system is only required to support 8-digit Singaporean phone numbers and standard international email formats for participant contact details.

Glossary

Mainstream OS: Windows, Linux, Unix, MacOS
Participant: A person who has registered to be part of the event.
Participant Record: The complete set of information stored about the participant.
RSVP: A participant's response indicating whether they will attend the event or not.
Prefix: A shorthand label used in commands to indicate specific fields (e.g. n/ for name)
Duplicate Participant: A participant entry that matches another participant’s unique identifying fields.
CSV (Comma-Separated Values): A file format used to store tabular data.

Appendix: Instructions for manual testing

Given below are instructions to test the app manually.

Note: These instructions only provide a starting point for testers to work on; testers are expected to do more exploratory testing.

Launch and shutdown

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.
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.
{ more test cases … }

Deleting a person

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.
{ more test cases … }

Saving data

Dealing with missing/corrupted data files
1. {explain how to simulate a missing/corrupted file, and the expected behavior}
{ more test cases … }

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

AB-3 Developer Guide

Acknowledgements

Setting up, getting started

Design

Architecture

UI component

Logic component

Model component

Storage component

Common classes

Implementation

[Proposed] Undo/redo feature

Proposed Implementation

Design considerations:

[Proposed] Data archiving

Documentation, logging, testing, configuration, dev-ops

Appendix: Requirements

Product scope

User stories

Use cases

Non-Functional Requirements

Glossary

Appendix: Instructions for manual testing

Launch and shutdown

Deleting a person

Saving data

FilesExpand file tree

DeveloperGuide.md

Latest commit

History

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File metadata and controls

AB-3 Developer Guide

Acknowledgements

Setting up, getting started

Design

Architecture

UI component

Logic component

Model component

Storage component

Common classes

Implementation

[Proposed] Undo/redo feature

Proposed Implementation

Design considerations:

[Proposed] Data archiving

Documentation, logging, testing, configuration, dev-ops

Appendix: Requirements

Product scope

User stories

Use cases

Non-Functional Requirements

Glossary

Appendix: Instructions for manual testing

Launch and shutdown

Deleting a person

Saving data