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

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Acknowledgements

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

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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 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.

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).
• 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)

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.

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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.

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.

{more aspects and alternatives to be added}

[Proposed] Data archiving

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

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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:

• has a need to manage a significant number of contacts
• need to log interactions with contacts
• prefer desktop apps over other types
• can type fast
• prefers typing to mouse interactions
• is reasonably comfortable using CLI apps

Value proposition: manage contacts and log interactions with contacts faster than a typical mouse/GUI driven app

Not in our scope:

• InternLink does not send emails or messages to the contacts
• InternLink cannot automatically sync with LinkedIn or other platforms
• Internlink cannot manage the internship application

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	refer to instructions when I forget how to use the App
* * *	user	add a new person
* * *	user	delete a person	remove entries that I no longer need
* * *	user	find a person by name	locate details of persons without having to go through the entire list
* * *	user	list all the people	browse my full directory
* * *	user	edit a contact information easily	keep my records accurate
* * *	user	add a new tag to one or more people	categorise contacts in different ways
* * *	user	delete a new tag to one or more people	keep tags up to date
* * *	user	edit a new tag to one or more people	keep tags up to date
* * *	user	filter contacts by one or multiple tags	find contacts that fall under specific categories
* *	user	hide private contact details	minimize chance of someone else seeing them by accident
* *	user	star/favourite contacts I access regularly	find high-priority connections quickly
* *	student who cannot remember exact details	search using flexible keyword matching	still find the correct contact even with without remembering fully
* *	student is waiting for a recruiter’s reply	mark a contact for follow-up by a specific date	remember to check in
* *	student who tends to procrastinate follow-ups	see overdue follow-up contacts	remember to check in with my contact
* *	user	schedule meetings with a contact	remember to meet with my contact
* *	user	edit meeting with a contact	keep meeting details up to date
* *	user	mark meetings as completed	keep meeting details up to date
* *	user	delete meetings with a contact	keep meeting details up to date
* *	student who forgets details of conversations	add interaction notes with a timestamp	recall what was discussed previously
* *	student	delete interaction notes	remove this interaction from the log
* *	student	edit interaction notes	update the interaction log with correct information
* *	student preparing for a follow-up email	review past interaction log	reference earlier conversations accurately
* *	user	delete contacts en masse	remove irrelevant contacts quickly
* *	user who meets people regularly	sort based on the last met date	see how long it has been since they contacted this person
* *	student managing many applications	see a list of contacts that have not had interaction in the past X days	maintain active communication
*	user with many persons in the address book	sort contacts lexicographically	locate a person easily
*	user who makes many typos	go to my last command quickly	quickly edit the command
*	user	undo multiple commands	easily reverse my actions
*	user	see the history of changes made in that session	know what changes I made

{More to be added}

Use cases

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

Use case: UC1 - Add a contact

MSS

1. User requests to add a new contact with name, phone number, and email.
2. InternLink checks whether the contact already exists.

3. InternLink saves the contact.

   Use case ends.

Extensions

• 2a. Duplicate detected. User confirms adding.

  Use case resumes at step 3.

• 2b. Duplicate detected. User cancels due to duplicate warning.

  Use case ends.

Use case: UC2 - Delete a contact

MSS

1. User requests to list persons.
2. InternLink shows a list of persons.
3. User requests to delete a specific person in the list.

4. InternLink deletes the person.

   Use case ends.

Extensions

• 2a. The list is empty.

  Use case ends.

• 3a. The given index is invalid.

  • 3a1. InternLink notifies the user of the error.

    Use case resumes at step 2.

Use case: UC3 - List contacts

MSS

1. User requests to list contacts.
2. InternLink retrieves all contacts from the contacts list.

3. InternLink displays the contacts sorted alphabetically.

   Use case ends.

Extensions

• 2a. Address book is empty.

  • 2a1. InternLink notifies the user of the error.

    Use case ends.

Use case: UC4 - Edit contact details

MSS

1. User requests to edit a specific contact.
2. User provides updated information (e.g. phone/email/company/role).
3. InternLink checks if the new information is a potential duplicate of existing contact.

4. InternLink updates the contact record.

   Use case ends.

Extensions

• 1a. No contacts match the request.

  • 1a1. InternLink notifies the user of the error.

    Use case ends.

• 3a. Duplicate detected. User confirms editing.

  Use case resumes at step 4.

• 3b. Duplicate detected. User cancels due to duplicate warning.

  Use case ends.

Use case: UC5 - Search contacts

MSS

1. User requests to search with keywords (name, email, tag, etc.).
2. InternLink scans all contacts for matches.

3. InternLink lists all matching contacts.

   Use case ends.

Extensions

• 1a. No contacts match the query.

  • 1a1. InternLink notifies the user of the error.

    Use case ends.

Use case: UC6 - Manage tags

MSS

1. User requests to create, edit, or delete a tag.
2. InternLink validates the tag name.
3. InternLink updates the tag list.

4. InternLink updates affected contacts if necessary.

   Use case ends.

Extensions

• 2a. Tag already exists when creating a new tag.

  • 2a1. InternLink notifies the user of the error.

    Use case ends.

• 2b. Tag does not exist when editing/deleting.

  • 2b1. InternLink notifies the user of the error.

  Use case ends.

Use case: UC7 - Assign tags to contacts

MSS

1. User requests to assign one or more tags to a contact or group of contacts.
2. InternLink adds the tags to the specified contacts.

3. InternLink updates the contacts.

   Use case ends.

Extensions

• 1a. At least one of the specified contacts exist, but some do not.

  • 1a1. InternLink skips the contacts that are not found.

  • 1a2. InternLink notifies the user of the contacts that were not found.

    Use case resumes at step 2.

• 1b. None of the specified contacts exist.

  • 1b1. InternLink notifies the user of the error.

    Use case ends.

• 1c. One or more tags do not exist.

  • 1c1. InternLink creates the missing tags.

    Use case resumes at step 2.

Use case: UC8 - Star contacts

MSS

1. User requests to star (favorite) a contact.
2. InternLink verifies if the contact exists.
3. InternLink stars the contact.

4. InternLink will show starred contacts at the top of the contacts list.

   Use case ends.

Extensions

• 2a. The specified contact does not exist.

  • 2a1. InternLink notifies the user of the error.

    Use case ends.

• 2b. The specified contact is already starred.

  • 2a1. InternLink notifies the user that the contact is already starred.

    Use case ends.

Use case: UC9 - Log interaction notes with a contact

MSS

1. User requests to log an interaction with a contact.
2. User enters interaction notes.
3. InternLink records the note with a timestamp.

4. InternLink stores it in the contact’s interaction history.

   Use case ends.

Extensions

• 1a. No contacts match the request.

  • 1a1. InternLink notifies the user of the error.

    Use case ends.

Use case: UC10 - Undo previous commands

MSS

1. User requests to view change history.
2. InternLink displays a list of changes made in the current session.
3. User selects a past change to revert to.

4. InternLink restores the contacts list state to that point.

   Use case ends.

Extensions

• 1a. No history exists.

  • 1a1. InternLink notifies the user that no previous commands have been entered.

    Use case ends.

• 3a. Selected history entry is invalid.

  • 3a1. InternLink notifies the user of the error.

    Use case resumes at step 2.

Non-Functional Requirements

1. Should work on any mainstream OS as long as it has Java 17 or above installed.
2. Should be able to hold up to 1000 contacts without a noticeable sluggishness in performance for typical usage.
3. 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.
4. Search and filtering operations (including multi-tag filtering) should complete within 1 second for up to 100 contacts.
5. The system should load the application within 2 seconds with 1000 contacts.
6. Each contact should be able to support up to 20 tags.
7. The application should automatically save changes after every successful command.
8. The application should prevent data corruption even if the program closes unexpectedly.
9. The application should try to recover all non-corrupted lines in the event of a data corruption.
10. All contacts and interaction logs should be persistently stored between sessions.

Glossary

• Mainstream OS: Windows, Linux, Unix, MacOS.
• Contact: A person stored in the addressbook, typically a recruiter, company representative, or professional connection whom the student met during networking or career events.
• Tag: A label assigned to a contact to categorize or organize them. Examples: Google, SWE, CareerFair2026, Referral. A contact may contain multiple tags.
• Multi-tagging: The ability to assign multiple tags to a single contact so that the contact can be categorized under multiple attributes such as company, role, or networking event.
• Interaction Log: A timestamped record of communication or interaction between the student and a contact. Examples include: interview, email, phone call, referral, career fair conversation.
• Interaction Notes: A single record inside the interaction log, containing: interaction type, timestamp, optional notes.
• Meeting: An upcoming event / meeting with a contact.

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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.

3. { more test cases …​ }

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.

2. { more test cases …​ }

Saving data

1. Dealing with missing/corrupted data files

   1. {explain how to simulate a missing/corrupted file, and the expected behavior}

2. { more test cases …​ }