JCRoster+ Developer Guide

---

Acknowledgements

This project is a brownfield software developed based on AddressBook Level-3, provided by the CS2103T teaching team.

---

Setting up, getting started

Refer to the guide Setting up and getting started.

---

Note: The terms “Person” and “Student” refer to the same entity and are used interchangeably throughout this guide and the application. Similarly, in the Design and Implementation sections, the term “AddressBook” has been retained instead of “JCRoster+” to remain consistent with the existing file and class names in the codebase.

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, Person Display, Command Guide Panel 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.

---

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.

---

Documentation, logging, testing, configuration, dev-ops

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

---

Appendix: Requirements

Product scope

Target user profile: Junior College Homeroom Teacher

Value proposition:

• Efficient Contact Management: Provides quick access to student details for Junior College homeroom teachers.
• Smart Tagging System: Enables quick categorization and seamless student grouping based on academic strengths.
• Administrative Convenience: Reduces the hassle of managing student information and classroom interactions.
• Improved Efficiency: Streamlines administrative tasks, allowing teachers to focus more on student engagement.

User stories

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

Use cases

(For all use cases below, the System is the JCRoster+ and the Actor is the JC Homeroom Teacher, unless specified otherwise)

Use case: Delete a person

MSS

1. JCRoster+ shows a list of persons.

2. User requests to delete specific person(s) in the list.

3. JCRoster+ deletes the person(s).

   Use case ends.

Extensions

• 1a. The list is empty.

  Use case ends.

• 2a. The given index is invalid.

  • 2a1. JCRoster+ shows an error message.

    Use case resumes at step 1.

Use case: Add a person

MSS

1. JCRoster+ prompts the user to enter student details (name, phone number, email, address, grades, and optional tags).

2. User enters the details in the specified format.

3. JCRoster+ validates the input.

4. JCRoster+ adds the person to the address book and displays a success message.

   Use case ends.

Extensions

• 2a. User enters an invalid name.

  • 2a1. JCRoster+ shows an error message.

    Use case resumes at step 1.

• 2b. User enters an invalid phone number (less than 3 or more than 15 digits).

  • 2b1. JCRoster+ shows an error message.

    Use case resumes at step 1.

• 2c. User enters an invalid email (incorrect format).

  • 2c1. JCRoster+ shows an error message.

    Use case resumes at step 1.

Use case: Find a person

MSS

1. JCRoster+ prompts the user to enter a name or keyword to search.

2. User enters the search query.

3. JCRoster+ searches the student list for matching names.

4. JCRoster+ displays a list of matching persons, if found.

   Use case ends.

Extensions

• 3a. No matches are found.

  • 3a1. JCRoster+ displays an empty list. Use case resumes at step 1.

Use case: Edit a student

MSS

1. JCRoster+ shows a list of students.

2. User requests to edit a student’s details using the edit command, specifying the student’s index and one or more fields to update.

3. JCRoster+ validates the input.

4. JCRoster+ updates the student’s information and displays a success message.

   Use case ends.

Extensions

• 1a. The list is empty.

  • 1a1. JCRoster+ shows an error message.
    Use case ends.

• 2a. The given index is invalid.

  • 2a1. JCRoster+ shows an error message.
    Use case resumes at step 1.

• 2b. No fields are provided for update.

  • 2b1. JCRoster+ shows an error message.
    Use case resumes at step 1.

• 3a. One or more input fields are invalid (e.g., invalid phone number, email, or grade format).

  • 3a1. JCRoster+ shows an error message.
    Use case resumes at step 1.

Use case: Add/Edit/Remove a remark for a student

MSS

1. JCRoster+ shows a list of students.

2. User requests to add, edit, or remove a remark for a specific student using the remark command with a specified index and remark content.

3. JCRoster+ validates the input.

4. JCRoster+ updates the student’s remark and displays a success message.

   Use case ends.

Extensions

• 1a. The list is empty.

  • 1a1. JCRoster+ shows an error message.
    Use case ends.

• 2a. The given index is invalid.

  • 2a1. JCRoster+ shows an error message.
    Use case resumes at step 1.

• 2b. The remark prefix r/ is missing or malformed.

  • 2b1. JCRoster+ shows an error message.
    Use case resumes at step 1.

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 persons 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. Should handle unexpected user inputs/system crashes gracefully by providing helpful error messages and not losing data.
5. Software should work without requiring an installer.
6. Data should be stored in a format that is easy to read and edit manually, in case the user wants to do so.

Glossary

• Mainstream OS: Windows, Linux, Unix, MacOS
• JC Homeroom Teacher: Singapore Junior College Homeroom/Form Teachers
• Student contact details: Refers to name, email, phone number, address

---

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. Run it using the command 'java -jar jcroster+.jar' 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.
      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.

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

   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 …​ }

---

Appendix: Planned Enhancements

Team Size: 4

1. UI Enhancement – Full Visibility of Command Guide Panel

Currently, the visibility of the Command Guide Panel may be limited depending on window size or layout constraints. We plan to enhance the user interface by ensuring that the Command Guide Panel is always fully visible, regardless of window state or resolution. This will improve usability by making the available commands consistently accessible to the user, reducing confusion and enhancing overall user experience.

2. UI Enhancement - Improve Responsiveness of Person Display Panel

Currently, the Person Display Panel takes in a Person object which is then displayed in the panel. If you use any command afterward that updates the state of the already displayed person, you will have to run the 'display' command again to see the updated information. We plan to improve this by ensuring that the Person Display Panel is always updated with the latest information of the displayed person. This will enhance the user experience by providing real-time updates and reducing the need for manual refreshes.

3. Feature Enhancement – Support for Multi-word Tags

Currently, tags are limited to single words, which restricts expressiveness when categorizing students. We plan to enhance the tagging functionality to support multi-word tags (e.g., “Needs Follow-Up”, “High Achiever”). This will allow users to add more descriptive and meaningful tags, improving the clarity and usefulness of student categorization.

4. Behavioural Enhancement – Preserve Displayed Subset After Command Execution

At present, the student list resets to display all students after each command, regardless of whether a filtered subset was shown prior. We plan to enhance this by retaining the previously displayed subset. For instance, if the user filters the list using the find command and then executes a remark command, the filtered subset will remain visible instead of reverting to the full list. This improvement ensures smoother workflows and a more intuitive user experience during focused tasks.

5. Data Validation Enhancement – Subject Field Input Checking

Currently, the application accepts any input in the subject fields, which may lead to inconsistent or invalid data. We plan to introduce validation that cross-checks subject entries against a predefined list of subjects offered at junior colleges (JCs). This enhancement will improve data integrity and prevent erroneous or unsupported subject entries, ensuring greater reliability of student academic records.

6. Usability Enhancement – More Specific and Actionable Error Messages

Currently, some of the application's error messages are general and may not provide users with enough information to understand what went wrong or how to fix it. We plan to enhance the user experience by replacing vague error messages with more specific and contextual ones that clearly indicate the cause of the error and suggest possible corrective actions. This will help users recover more efficiently from mistakes and reduce frustration during usage.