Developer Guide

• Setting up, getting started
• Design
  • Architecture
  • UI component
  • Logic component
  • Model component
  • Storage component
  • Common classes
• Implementation
  • Tagging system
  • Tutorial Tags
  • Available Command
  • Find Command
  • Stateful Utility Classes
  • [Proposed] Undo/redo feature
    • Proposed Implementation
    • Design considerations:
• Documentation, logging, testing, configuration, dev-ops
• Appendix: Requirements
  • Product scope
  • User stories
  • Use cases
  • Non-Functional Requirements
  • Glossary
• Appendix: Planned Enhancements
• Appendix: Instructions for manual testing
  • Launch and shutdown
  • Deleting a person
  • Saving data

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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("mark 1 /t Assignment1 /ts cg") 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., MarkCommandParser) 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., MarkCommand) 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.addressbook.commons package.

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Implementation

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

Tagging system

TrAcker helps users track assignment status, tutorial attendance and tutorial groups via the Tagging system. The class diagram below depicts how different types of Tags are implemented:

We use a Set<Tag> to store the set of tags for each Student / TA, such that Tags are uniquely identified by their tagName. Note that TAs may only have TutorialTag.

Tutorial Tags

Users may only mark persons with valid TutorialTags they have previously defined using tuttag add. The following activity diagram depicts a typical flow of how a user would add a new tutorial group.

Available Command

TrAcker allows users to find available TAs for a specific tutorial group. The AvailableCommandParser parses the user’s input and creates an AvailableCommand containing a TutorialTagContainsGroupPredicate. The AvailableCommand is then executed by LogicManager to update the FilterPersonList in the Model. This retrieves the list of available TAs for the specified tutorial group. The workflow is shown below.

Find Command

The find command filters persons in the current displayed list based on the user specified flags. Here we provide a brief summary of the specific behaviour of the find command:

• The search is case-insensitive
• When searching by name, we perform subword matching e.g. Han will match Hans
• Between optional fields supplied, an AND search is performed (e.g. find stu /n John /i 6Z will find all Students who have both a name containing John and an ID containing 6Z.)
• For multiple values supplied to the same field, an OR search is performed.
• Searching by Tags:
  • For TutorialTags, subword matching is performed (e.g. find /t wed assignment1 will find all persons with a TutorialTag where wed is a subword or an assignment1 tag.)
    • This is to make it easier for TAs to search by the day of the week for Tutorial tags.
  • As follows, for other types of tags, full word matching is performed.

The below sequence diagram depicts the process of a user executing the find command:

Stateful Utility Classes

The ParserUtil and StringUtil classes were originally classes that provide utility APIs for parsing and string operations. Upon noticing the need that some parsing and string operations require state information of the current model, both classes are updated to record the state information and follow the singleton pattern. They are renamed StatefulParserUtil and StatefulStringUtil.

For both classes,

• An initialize() method is provided to initialize with the current model. This method should only be called once.
• An getInstance() method is provided to access the private field model that captures the state information
• Some utility methods can now use the state information (e.g. the current filtered list of persons) to achieve their functionalities.

[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}

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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:

• Head TA of CS2103T
• has a need to manage a significant number of contacts of students and other TAs
• prefer desktop apps over other types
• can type fast
• prefers typing to mouse interactions
• is reasonably comfortable using CLI apps

Value proposition: manage students and TAs faster than a typical mouse/GUI driven app

User stories

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

Priority	As a …​	I want to …​	So that I can…​
* * *	user	mark students’ attendance	view attendance records easily in the app.
* * *	user	add a contact entry
* * *	user	delete a contact entry
* * *	user	add tags
* * *	user	delete tags
* * *	user	edit a contact entry
* * *	user	search for specific contacts	easily retrieve the contact info of a student/tutor if I need to contact them.
* * *	user	have a basic GUI to interact with	use the app conveniently instead of in shell/terminal.
* *	user with many students and tutors to manage	send group emails to students/tutors	save time on gathering email addresses.
* *	user	organize students into classes	separate records for students from different classes.
* *	beginner user	access a user guide	understand the functions of the app.
* *	potential user exploring the app	see the app populated with sample data	get an idea of how the app is used.
* *	user with many students and tutors to manage	filter contacts with relevant keywords or tags	access records relevant to a specific keyword quickly.
* *	novice user	expect the commands to be common-sensical	pick up the app at speed.
* *	novice user	expect warnings to be given to irreversible actions such as batch delete contacts	will not lose my data out of unfamiliarity with the commands.
* *	frequent user	batch edit contacts	make similar changes to a large number of contacts quickly.
* *	user	see which tutors are available	quickly allocate them for replacement tutoring.
* *	novice user	have a sleek and simple UI	use the app easily.
* *	careless user	backup the last few edits	revert changes if necessary.
* *	user	track students’ assignment progress	follow up if necessary.
* *	user	edit tags	easily customise existing tags for my use case.
* *	careless user	backup the last few edits	revert changes if necessary.
*	expert user	export data in .xlsx	share records with other tutors.
*	expert user	create shortcuts for specific commands	perform the usual tasks quickly.
*	user with lots of data stored	batch imports to have a timestamp	easily locate certain information based on import time, or batch delete them when obsolete.
*	novice user	accessible help page to remind me of command keywords	carry out tasks quickly even without remembering the command keywords.
*	user	generate attendance reports of the students	see who has been skipping classes.
*	busy user	receive reminders for upcoming classes	keep track of my upcoming lessons.
*	impatient user	use the app offline	use the app even when the connection is poor.
*	user who is familiar with cli	be able to access already executed commands	execute them again when needed without having to type everything again.
*	user who is familiar with cli	see a list of suggested commands after having typed the initial letters of a keyword	quickly select a command to complete and it is less likely that I misspell a command.
*	beginner user	GUI to be simple and self-explanatory	get familiar with the app easily.

Use cases

(For all use cases below, the System is the TrAcker, the Actor is the user and persons can be both a student and a TA unless specified otherwise)

Use case: Delete a person

MSS

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

4. AddressBook deletes the person

   Use case ends.

Extensions

• 2a. The list is empty.

  Use case ends.

• 3a. The given index is invalid.

  • 3a1. TrAcker shows an error message.

    Use case resumes at step 2.

Use case: Add a person

MSS

1. User requests to add a person with relevant entries such as name, phone number and email

2. TrAcker adds the entry to its contact list

   Use case ends.

Extensions

• 1a. User inputs information in incorrect format

  • 1a1. TrAcker shows an error message.

    Use case resumes at step 1

Use case: Search a contact

MSS

1. User requests to search a contact by keywords (for names)

2. TrAcker shows a list of contacts whose names match the keywords

   Use case ends.

Extensions

• 1a. No contacts have names including the specified keywords.

  *1a1. TrAcker shows an empty list

  Use case ends.

Use case: Edit a contact

MSS

1. User requests to edit a contact with new information

2. TrAcker updates the contact with specified new information

   Use case ends.

Extensions

• 1a. User inputs new information in incorrect format

  • 1a1. TrAcker shows an error message.

    Use case resumes at step 1

Non-Functional Requirements

1. (Technical) Should work on any mainstream OS as long as it has Java 11 or above installed.
2. (Quality) 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.
3. (Quality) The user interface and commands should be intuitive and user-friendly, requiring minimal time to learn.
4. (Quality) The app should provide clear and informative error messages in case of invalid inputs or command failures.
5. (Performance) The app should respond to user actions within 0.5 seconds, ensuring smooth navigation and interaction.
6. (Performance) The app should be able to support at minimum a contacts list of 200 without affecting performance.
7. (Performance) The app should be able to run smoothly even on low-end hardware configurations.
8. (Process) The project is expected to adhere to a schedule that adds updates incrementally at least once every two weeks.
9. (Project scope) The product should be focused on the needs of our target user, CS Head Teaching Assistants.
10. (Documentation) Comprehensive user guide should be provided, with detailed instructions on how to use each command.
11. (Documentation) Comprehensive developer guide should be created to facilitate ongoing maintenance of the app.

Glossary

• Mainstream OS: Windows, Linux, Unix, MacOS
• Tutor: A teaching assistant for CS2103T
• Student: A student taking CS2103T
• Tag: A label that can be attached to the student/TA. It can represent a Tutorial Group, Attendance or Assignment.
• Tag Status: The current status of a student’s tag. More details can be found in the User Guide.
• Contact Entry: Contact information of either a student or a TA, containing the name, ID, phone number, email.

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Appendix: Planned Enhancements

Team size: 5

1. Restrict actions on TutorialTags for clarity: As of now, there is nothing restricting users from doing tuttag add /t TUE08 followed by mark 1 /t TUE08 /ts cg, i.e. the TutorialTag TUE08 is being treated as an AssignmentTag by being assigned the TagStatus cg, and is moved to the first row. This can be confusing if users forget their Tutorial / Assignment tags. For future versions of TrAcker we intend to make the distinction between different types of tags clearer by restricting the possible TagStatus of TutorialTags.

2. Restrict TutorialTag status for Students: Currently Students get have a TutorialTag marked as “AVAILABLE” by entering for instance mark 1 /t TUE08 /ts av. However, this is likely not very useful for TAs and becomes problematic if the same Student is to be assigned the tutorial group TUE08. Thus we plan to also restrict Students to only be able to have TutorialTags with an ASSIGNED TagStatus.

3. Enhance information prompts: Some of the information / error messages in TrAcker can be improved for clarity. For example running the clear command leaves the previous information still in the information prompt. For future versions of TrAcker we plan to clear out the information panel in order to show messages relevant the current command being run.

4. Improve GUI to handle longer inputs: One of the limitations of TrAcker’s current GUI is that long input text gets truncated if the window size is small (or, on extreme inputs, text can be truncated in a full-sized window). We intend to work on enhancing the flexibility of our GUI in order to handle longer input lengths by adding a scroll pane if lengths are too long.

5. Making Phone Number an optional field: Currently, TrAcker functions similarly to an address book where phone number is a compulsory field when adding a person. However, students’ phone numbers may not be available nor relevant data which TAs require. Thus in order to make the process of adding students smoother, we plan to make the phone number field optional in the future.

6. Making parsing of phone number and email stricter: Currently, TrAcker does not limit the number of characters in the phone number field, and accepts any string with ‘@’ as a valid email input. We plan to accept only 3-15 characters in the phone number field, and accept only valid email addresses in the future.

7. Import / Export from .csv: Currently TrAcker relies on users manually adding student / TA data using the add command. This can be quite time-consuming, especially if users are trying to migrate student / TA data from existing systems in .csv format. Thus we plan to include a feature to import data from .csv format (where all required fields are filled in). Similarly, we also intend to develop an Export feature for users to export their list of Student / TA data into .csv format for added convenience.

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 …​ }