GreyBook Developer Guide

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Acknowledgements

• This project is based on the AddressBook-Level3 project created by the SE-EDU initiative.

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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 GreyBookParser 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 GreyBookParser 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 GreyBookParser 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 GreyBook 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 GreyBook data and user preference data in JSON format, and read them back into corresponding objects.
• inherits from both GreyBookStorage 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 greynekos.greybook.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 VersionedGreyBook. It extends GreyBook with an undo/redo history, stored internally as an GreyBookStateList and currentStatePointer. Additionally, it implements the following operations:

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

These operations are exposed in the Model interface as Model#commitGreyBook(), Model#undoGreyBook() and Model#redoGreyBook() 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 VersionedGreyBook will be initialized with the initial GreyBook state, and the currentStatePointer pointing to that single GreyBook state.

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

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

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#undoGreyBook(), which will shift the currentStatePointer once to the left, pointing it to the previous GreyBook state, and restores the GreyBook 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#redoGreyBook(), which shifts the currentStatePointer once to the right, pointing to the previously undone state, and restores the GreyBook to that state.

Step 5. The user then decides to execute the command list. Commands that do not modify the GreyBook, such as list, will usually not call Model#commitGreyBook(), Model#undoGreyBook() or Model#redoGreyBook(). Thus, the GreyBookStateList remains unchanged.

Step 6. The user executes clear, which calls Model#commitGreyBook(). Since the currentStatePointer is not pointing at the end of the GreyBookStateList, all GreyBook 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 GreyBook.

  • 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 club activities and members
• prefer desktop apps over other types
• can type fast
• prefers typing to mouse interactions
• is reasonably comfortable using CLI apps

Value proposition: Optimised contact management system for clubs and societies, supporting the administration of common club activities like projects or competitions.

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 GreyBook and the Actor is the user, unless specified otherwise)

Use case: Add a member

MSS

1. User requests to add a specific member to the list, providing their name, email, phone number, studentID, and role.

2. GreyBook adds the member

3. GreyBook shows a success message

   Use case ends.

Extensions

• 1a. The command format is invalid.
  • 1a1. GreyBook shows an error message.
• 1b. The arguments do not follow the correct format.
  • 1b1. GreyBook shows an error message.
• 1c. Another member in the list shares the same studentID
  • 1c1. GreyBook shows an error message. Use case resumes at step 2.

Use case: Delete a member

MSS

1. User requests to list members

2. GreyBook shows a list of members

3. User requests to delete a specific member in the list, providing their index in the list, or their studentID.

4. GreyBook deletes the member

5. GreyBook shows a success message

   Use case ends.

Extensions

• 2a. The list is empty.

  Use case ends.

• 3a. The given index is invalid.

  • 3a1. GreyBook shows an error message

    Use case resumes at step 2.

• 3b. The given studentID does not exist.

  • 3b1. GreyBook shows an error message, possibly suggests a similar studentID

    Use case resumes at step 2.

Use Case: Mark Attendance for a member

MSS

1. User requests to list members
2. GreyBook shows a list of members
3. User requests to mark a member's attendance, providing index/studentID and attendance status
4. GreyBook records the attendance status
5. GreyBook shows a success message

Use case ends.

Extensions

• 2a. The list is empty.

  Use case ends.

• 3a. The index is invalid

  • 3a1. GreyBook shows an error message

    Use case resumes at step 2.

• 3b. The studentID does not exist in the system.

  • 3b1. GreyBook shows an error message

  Use case resumes at step 2.

• 3c. The attendance status is invalid

  • 3c1. GreyBook shows an error message

    Use case resumes at step 2.

Use Case: Export Attendance to CSV

MSS

1. User requests to export attendance data
2. GreyBook generates a CSV file with the attendance data
3. GreyBook prompts the user to download the CSV file
4. User downloads the file

Use case ends.

Extensions

• 1a. No attendance data exists

  • 1a1. GreyBook shows a info message

    Use case ends

• 4a. Error occurred while trying to write CSV data to file

  • 4a1. GreyBook shows an error message, prompts user to try downloading again

    Use case resumes at step 3.

{More to be added}

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. The application should efficiently handle and store member and attendance data in a human readable format such as JSON without degrading performance as data grows.

{More to be added}

Glossary

• Mainstream OS: Windows, Linux, Unix, MacOS
• Private contact detail: A contact detail that is not meant to be shared with others

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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 A0123456J (assuming a person with this student ID exists)
      Expected: Contact with student ID A0123456J is deleted from the list. Details of the deleted contact shown in the status message. Timestamp in the status bar is updated.

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

   5. Test case: delete A9999999W (assuming no person with this student ID exists)
      Expected: No person is deleted. Error message "Error, user does not exist." shown in the status message.

   6. Other incorrect delete commands to try: delete, delete x, delete INVALID_STUDENTID, ... (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 …​ }