DeveloperGuide.md

layout	page
title	Developer Guide

• Table of Contents {:toc}

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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 each component.

💡 Tip: The .puml files used to create diagrams in this document can be found in the diagrams folder. Refer to the PlantUML Tutorial at se-edu/guides to learn how to create and edit diagrams.

Main has two classes called Main and MainApp. It is responsible for,

• At app launch: Initializes the components in the correct sequence, and connects them up with each other.
• At shut down: Shuts down the components and invokes cleanup methods where necessary.

Commons represents a collection of classes used by multiple other components.

The rest of the App consists of 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.

Each of the four components,

• defines its API in an interface with the same name as the Component.
• exposes its functionality using a concrete {Component Name}Manager class (which implements the corresponding API interface mentioned in the previous point.

For example, the Logic component (see the class diagram given below) defines its API in the Logic.java interface and exposes its functionality using the LogicManager.java class which implements the Logic interface.

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.

The sections below give more details of each component.

UI component

API : 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.

The UI component uses 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.

Logic component

API : Logic.java

1. Logic uses the AddressBookParser class to parse the user command.
2. This results in a Command object which is executed by the LogicManager.
3. The command execution can affect the Model (e.g. adding a person).
4. The result of the command execution is encapsulated as a CommandResult object which is passed back to the Ui.
5. In addition, the CommandResult object can also instruct the Ui to perform certain actions, such as displaying help to the user.

Given below is the Sequence Diagram for interactions within the Logic component for the execute("delete 1") API call.

ℹ️ **Note:** The lifeline for `DeleteCommandParser` should end at the destroy marker (X) but due to a limitation of PlantUML, the lifeline reaches the end of diagram.

Model component

API : Model.java

The Model,

• stores a UserPref object that represents the user’s preferences.
• stores the address book data.
• exposes 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.
• does not depend on any of the other three components.

ℹ️ **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` object.

Storage component

API : Storage.java

The Storage component,

• can save UserPref objects in json format and read it back.
• can save the address book data in json format and read it back.

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 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.

ℹ️ **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.

ℹ️ **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 the undo operation works:

ℹ️ **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.

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.

ℹ️ **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 consideration:

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:

• is the store manager of a T*ger Sugar milk tea shop
• is very busy with daily operations and has little time for manual writing or recording
• is a fast typist
• has many employees (both part-time and full-time) to manage
• needs to save all the employees’ contact numbers
• needs to forward one person’s contact to another employee to let them directly communicate with each other
• cares about the daily revenue
• does an inventory check daily to ensure that ingredients are sufficient for the shop to operate smoothly
• needs to keep track of the daily revenue
• prefers desktop apps over other types
• prefers typing to mouse interactions
• is reasonably comfortable using CLI apps

Value proposition:

• To manage the employees' contact information digitally
  • The product will provide a platform to allow the user to save his/ her employees’ contact information (eg. emergency contacts, address etc).
  • It can manage contacts faster than a typical mouse/GUI driven app
• To digitise inventory keeping
  • The product will help to digitise inventory keeping, and thus helps to save the user’s time and prevent human error in calculation. It does not ensure that the employees use the same amount of ingredients in making the drinks. The user only needs to enter the number of each type of bubble tea sold on the day. It will notify the user which ingredients are running low on stock and remind him/ her to restock them soon.
  • The product could also help the user calculate the total cost for restocking.
• To digitise daily revenue tracking
  • Given the number of each type of bubble tea sold, the product can provide the user with the revenue for each day.
  • The product also helps Amy to keep track of the daily revenue changes, and the revenue for each type of product. This would allow Amy to check which kind of bubble tea sells better and consider adopting similar ideas when making new products.

User stories

Priorities: 1 (must have), 2 (nice to have), 3 (unlikely to have)

As a/an	I can/I want to (features that are going to be implemented)	So that (benefit gained)	Priority
Store manager	have a centralised system that helps me keep track of my employees’ contact numbers	I don't need to organize working contacts on my personal phone	1
Store manager	have a software that helps me on daily inventory checking	I can reduce the amount of human errors that may be involved and track the shop's inventory conveniently	1
Busy store manager	receive reminders to restock	I won't lose revenue because of unexpected ingredient shortage during operation	1
First-time user	be able to download the app	I can play around and check out what it can do before actual usage	1
First-time user	use the help feature	I can get more familiar with the app features	1
First-time user	find out if the app is running smoothly and bug-free	I can decide if using this app will indeed help me run a store	1
Concerned manager	check the employees's contact number if they are absent without stating any reasons	I can easily contact them in a short time	1
Second-time user	initialize the ingredients level in the app	I need not remember the amount of inventories, and only need to update when I do a restock	1
Second-time user	find the emergency contacts of my employees quickly if they are injured	I can find the person to contact and know what action to take in the shortest time possible	1
Intermediate user	input the number of each type of drinks sold into tCheck at the end of the day, and know the amount of remaining ingredients	I can document the amount of ingredients left	1
Expert user	to delete some of the employees' data who are no longer working at the shop	they are no longer tracked by the app.	1
Second-time user	view the revenue from the last day	I can predict how much demand it would likely to be for today	1
Store manager	have a software to help me calculate my daily revenue	I don't need to manually calculate them and it will become less troublesome to do so	2
Busy and concenrned store manager	have a software to remind me on check my employees' health condition for each shift	I won't forget to check, espcially when I'm busy	2
First-time user	read the "About" page in the app	I know how to use this software to help my business	2
First-time user	register for a password-protected account	I can be sure that my user data will not be viewed by non-users	2
First-time user	be able to navigate the app easily	I only need basic intuition to use the navigation bar (For GUI)	2
Impatient first-time user	have a fast-response inventory keeping application	I don't waste time waiting for the app to load	2
Second-time user	only use the software and access my data if I enter the correct login information	it prevents unauthorised users from viewing the shop's information	2
Second-time user	be reminded of the task of checking the employee's health condition	I would not forget to check the employees' health status each day before the shop opens	2
Concerned manager	check and record the health conditions of my employees	I can do my best to ensure the safety of food is guanranteed	2
Second-time user	view the inventory from the last day	I can restock before the ingredients ran out of stock and affect my business	2
Intermediate user	input the number of each type of drinks sold into tCheck at the end of the day,and find out the total revenue of the day	I can document the daily revenue	2
Intermediate user	do closing duties according to a check list shown on the app	I will not forget important things	2
Intermediate user	use the ingredient data	I can prepare for next day's ingredients	2
Busy store manager	use shortcut commands	it makes my input process into tCheck faster and more convenient.	2
Expert user	my data to be saved reliably	my data won't be lost even if my computer crashes	2
Expert user	have fast responses after a long usage period	I will not waste time waiting for the app even after extensive usage	2
Expert user	export my data from the application	the performace of the store can be analyzed easily by using other third-party softwares	2
Intermediate user	to look through my employees' health condition data of the last 10 days	I can roughly gauge the conditions of my employees	3

{More to be added}

Use cases

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

Use Case: UC01 - Archive a contact detail of an employee

MSS

1. User chooses to archive one employee’s contact details.

2. tCheck requests for details of the employee to archive.

3. User enters the archive details.

4. tCheck will move this corresponding contact detail into the archive and displays a success message.

   Use case ends.

Extensions

• 3a. tCheck detects an incorrect input format or is unable to find the entered data.

    * 3a1. tCheck requests for the correct data.
    
    * 3a2. User enters new data.
    
    Steps 3a1-3a2 are repeated until the data entered are correct.
    
    Use case resumes from step 4.
  

Use Case: UC02 - Archive all contact details

MSS

1. User chooses to archive all employee’s contact details.

2. User enters the request to archive all employees’ contact details.

3. tCheck will move all contact details into the archive and displays a success message.

   Use case ends.

Extensions

• 2a. tCheck detects an incorrect input format.

    * 2a1. tCheck requests for the input to be in the correct format.
    
  	* 2a2. User enters new data.
  	
  	Steps 2a1-2a2 are repeated until the data entered are correct.
  	
  	Use case resumes from step 3.
  

• 2b. tCheck detects an empty contact list.

    * 2b1. tCheck shows a warning message.
    
    Use case ends.
  

UC03 - Set ingredient level for a single ingredient

MSS

1. User chooses to set the ingredient level for an ingredient.

2. tCheck requests for the name of the ingredient.

3. User enters the name of the ingredient.

4. tCheck requests for the amount of the particular ingredient.

5. User enters the amount of the particular ingredient.

6. tCheck will set the ingredient level for this ingredient and displays a success message.

    Use case ends.
   

Extensions

• 3a. tCheck is unable to find the entered name.

    * 3a1. tCheck requests for the correct data.
    
    * 3a2. User enters new data.
    
    Steps 3a1-3a2 are repeated until the data entered are correct.
    
  	Use case resumes from step 4.
  

• 5a. tCheck detects an invalid amount value

    * 5a1. tCheck requests for the correct data.
    
    * 5a2. User enters new data.
    
    Steps 5a1-5a2 are repeated until the data entered are correct.
    
   	Use case resumes from step 6.
  

UC05 - Set sales level for all types of drinks

MSS

1. User chooses to set the sales volume for a type of drink.

2. tCheck requests for the drink name.

3. User enters the name of the drink.

4. tCheck requests for the number of that type of drink sold on that day.

5. User enters the number of that type of drink sold.

6. tCheck will set the sales level for this drink and displays a success message. Steps 1-6 are repeated until the sales of all types of drinks are updated.

   Use case ends.

Extensions

• 3a. tCheck is unable to find the entered name.

    * 3a1. tCheck requests for the correct data.
    
    * 3a2. User enters new data.
    
    Steps 3a1-3a2 are repeated until the data entered are correct.
    
  	Use case resumes from step 4.
  

• 5a. tCheck detects an invalid sales amount.

    * 5a1. tCheck requests for the correct data.
    
    * 5a2. User enters new data.
    
    Steps 5a1-5a2 are repeated until the data entered are correct.
    
    Use case resumes from step 6.
  

{More to be added}

Non-Functional Requirements

1. Should work on any mainstream OS as long as it has Java 11 or above installed.
2. Should be able to hold up to 1000 persons without a noticeable sluggishness in performance for typical usage.
3. Should be able to respond within 1 second for each operation.
4. Should be able to function fully without connecting to internet.
5. Should be for a single user.
6. Should not handle the printing of the report (i.e. sales report).
7. 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.
8. A user without prior experience on inventory management system should be able to accomplish most of the tasks using commands.

{More to be added}

Glossary

• Mainstream OS: Windows, Linux, Unix, OS-X
• 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.

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

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 …​ }