Hallper - Developer Guide

By: Team W16-1 Since: Aug 2018 Licence: MIT

1. Introduction
2. Setting up
3. Design
4. Implementation
5. Documentation
6. Testing
7. Dev Ops
Appendix A: Suggested Programming Tasks to Get Started
- A.1. Improving each component
- A.2. Creating a new command: remark
Appendix B: Product Scope
Appendix C: User Stories
Appendix D: Use Cases
Appendix E: Non Functional Requirements
Appendix F: Glossary
Appendix G: Instructions for Manual Testing

1. Introduction

Hallper is a desktop application aimed at serving the Junior Common Room Committees (JCRCs) of the Halls of NUS. Hallper follows an event-driven architecture, and is designed to work on any mainstream operating system (OS). This guide provides you with information on how to contribute to Hallper, whether you are a new or experienced developer.

2. Setting up

This section tells you how to set up your computer before you can start working on Hallper.

2.1. Prerequisites

JDK 9 or later

JDK 10 on Windows will fail to run tests in headless mode due to a JavaFX bug. Windows developers are highly recommended to use JDK 9.
IntelliJ IDE

IntelliJ by default has Gradle and JavaFx plugins installed.
Do not disable them. If you have disabled them, go to File > Settings > Plugins to re-enable them.

2.2. Setting up the project in your computer

Follow these steps to set up the project on your computer:

Fork this repository, and clone the fork to your computer.
Open IntelliJ (If you are not in the welcome screen, click File > Close Project to close the existing project dialog first).
Set up the correct JDK version for Gradle.
1. Click Configure > Project Defaults > Project Structure.
2. Click New… and find the directory of the JDK.
Click Import Project.
Locate the build.gradle file and select it. Click OK.
Click Open as Project.
Click OK to accept the default settings.
Open a console and run the command gradlew processResources (Mac/Linux: ./gradlew processResources). It should finish with the BUILD SUCCESSFUL message.
This will generate all resources required by the application and tests.

2.3. Verifying the setup

Follow these steps to verify the setup:

Run the seedu.address.MainApp and try a few commands.
Run the tests to ensure they all pass.

2.4. Configurations before writing code

2.4.1. Configuring the coding style

This project follows oss-generic coding standards. IntelliJ’s default style is mostly compliant with ours but it uses a different import order from ours. To rectify:

Go to File > Settings… (Windows/Linux), or IntelliJ IDEA > Preferences… (macOS).
Select Editor > Code Style > Java.
Click on the Imports tab to set the order.
- For Class count to use import with '*' and Names count to use static import with '*': Set to 999 to prevent IntelliJ from contracting the import statements.
- For Import Layout: The order is import static all other imports, import java.*, import javax.*, import org.*, import com.*, import all other imports. Add a <blank line> between each import.

Optionally, you can follow the UsingCheckstyle.adoc document to configure Intellij to check style-compliance as you write code.

2.4.2. Updating documentation to match your fork

After forking the repo, the documentation will still refer to the CS2103-AY1819S1-W16-1/main repo.

If you plan to develop this fork as a separate product (i.e. instead of contributing to CS2103-AY1819S1-W16-1/main), you should do the following:

Configure the site-wide documentation settings in build.gradle, such as the site-name, to suit your own project.
Replace the URL in the attribute repoURL in DeveloperGuide.adoc and UserGuide.adoc with the URL of your fork.

2.4.3. Setting up CI

Set up Travis to perform Continuous Integration (CI) for your fork. See UsingTravis.adoc to learn how to set it up.

After setting up Travis, you can optionally set up coverage reporting for your team fork (see UsingCoveralls.adoc).

Coverage reporting could be useful for a team repository that hosts the final version but it is not that useful for your personal fork.

Optionally, you can set up AppVeyor as a second CI (see UsingAppVeyor.adoc).

Having both Travis and AppVeyor ensures your App works on both Unix-based platforms and Windows-based platforms (Travis is Unix-based and AppVeyor is Windows-based)

2.4.4. Getting started with coding

When you are ready to start coding:

Get some sense of the overall design by reading Section 3.1, “Architecture”.
Take a look at Appendix A, Suggested Programming Tasks to Get Started.

3. Design

This section describes the architecture and components of the application.

3.1. Architecture

Figure 3.1.1: Architecture Diagram

The Architecture Diagram given above explains the high-level design of the App. Given below is a quick overview of each component:

The .pptx files used to create diagrams in this document can be found in the diagrams folder. To update a diagram, modify the diagram in the pptx file, select the objects of the diagram, and choose Save as picture.

Main has only one class called MainApp. It is responsible for:

At app launch: Initialising the components in the correct sequence, and connecting them up with each other.
At shut down: Shutting down the components and invoking cleanup method where necessary.

Commons represents a collection of classes used by multiple other components. Two of those classes play important roles at the architecture level:

EventsCenter : This class (written using Google’s Event Bus library) is used by components to communicate with other components using events (i.e. a form of Event Driven design).
LogsCenter : Used by many classes to write log messages to the App’s log file.

The rest of the App consists of four components:

UI: Controls the UI of the App.
Logic: Executes commands.
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 {Component Name}Manager class.

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

Figure 3.1.2: Class Diagram of the Logic Component

Events-Driven nature of the design

The Sequence Diagram below shows how the components interact for the scenario where the user issues the command delete 1.

Figure 3.1.2: Component interactions for delete 1 command (part 1)

Note how the Model simply raises a AddressBookChangedEvent when the Address Book data are changed, instead of asking the Storage to save the updates to the hard disk.

The diagram below shows how the EventsCenter reacts to that event, which eventually results in the updates being saved to the hard disk and the status bar of the UI being updated to reflect the 'Last Updated' time.

Figure 3.1.3: Component interactions for delete 1 command (part 2)

Note how the event is propagated through the EventsCenter to the Storage and UI without Model having to be coupled to either of them. This is an example of how this Event Driven approach helps us reduce direct coupling between components.

The sections below give more details of each component.

3.2. UI component

Figure 3.2.1: Structure of the UI Component

API : Ui.java

The UI consists of a MainWindow that is made up of parts e.g.CommandBox, ResultDisplay, PersonListPanel, StatusBarFooter, BrowserPanel 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.
Binds itself to some data in the Model so that the UI can auto-update when data in the Model change.
Responds to events raised from various parts of the App and updates the UI accordingly.

3.3. Logic component

Figure 3.3.1: Structure of the Logic Component

API : Logic.java

The Logic component consists of all the Command and Parser classes. It makes use of AddressBookParser to parse all user commands.

A typical flow in the Logic component is given below:

Logic uses the AddressBookParser class to parse the user command.
This results in a Command object which is executed by the LogicManager.
The command execution can affect the Model (e.g. adding a person) and/or raise events.
The result of the command execution is encapsulated as a CommandResult object which is passed back to the UI.

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

Figure 3.3.2: Interactions Inside the Logic Component for the delete 1 Command

3.4. Model component

Figure 3.4.1: Structure of the Model Component

API : Model.java

The Model component consists of classes that model objects e.g. Person, Calender, Email, etc. It does not depend on any of the other three components.

The Model component:

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.

As a more OOP model, we can store a Tag list in Address Book, which Person can reference. This would allow Address Book to only require one Tag object per unique Tag, instead of each Person needing their own Tag object. An example of how such a model may look like is given below.

3.5. Storage component

Figure 3.5.1: Structure of the Storage Component

API : Storage.java

The Storage component consists of classes which are responsible for saving and reading files.

The Storage component:

saves UserPref objects in json format and reads it back.
saves the Address Book data in xml format and reads it back.
saves emails in eml format and reads it back.
saves calendars in ics format and reads it back.
saves the Budget Book data in xml format and reads it back.

3.6. Commons

Commons consists of classes used by multiple components and are located in the seedu.addressbook.commons package.

4. Implementation

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

4.1. Undo/Redo feature

4.1.1. Current Implementation

The 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.

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.

If the currentStatePointer is at index 0, pointing to the initial address book state, then there are no previous address book 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:

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.

If the currentStatePointer is at index addressBookStateList.size() - 1, pointing to the latest address book state, then there are no undone address book 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. We designed it this way because 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:

4.1.2. 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: Must ensure that the implementation of each individual command are correct.

Aspect: Data structure to support the undo/redo commands

Alternative 1 (current choice): Use a list to store the history of address book states.
- Pros: Easy for new Computer Science student undergraduates to understand, who are likely to be the new incoming developers of our project.
- Cons: Logic is duplicated twice. For example, when a new command is executed, we must remember to update both HistoryManager and VersionedAddressBook.
Alternative 2: Use HistoryManager for undo/redo
- Pros: Do not need to maintain a separate list, and just reuse what is already in the codebase.
- Cons: Requires dealing with commands that have already been undone: We must remember to skip these commands. Violates Single Responsibility Principle and Separation of Concerns as HistoryManager now needs to do two different things.

4.2. Email feature

Written below is the implementation of the Email feature, and considerations in its design.

4.2.1. Current Implementation

Figure 4.2.1.1: Activity diagram of ComposeEmailList.

The Email feature works using a third-party dependency, Simple Java Mail. It allows .eml files to be created and saved onto the computer. The feature is facilitated by EmailModel and EmailDirStorage. A simple activity diagram depicting how ComposeEmailList works is shown above in Figure 4.2.1.1. It implements the following operations:

EmailModel#saveComposedEmail(Email email) — Stores each newly composed email in the EmailModel.
EmailDirStorage#saveEmail(EmailModel email) — Saves the newly composed email in the EmailModel to the computer.

These operations are exposed in the Model interface as Model#saveComposedEmail(Email email), and in the Storage interface as Storage#saveEmail(EmailModel email) respectively.

Figure 4.2.1.2: Sequence diagram of ComposeEmailList.

Given below is an example usage scenario and how the Compose feature behaves at each step:

Step 1. The user executes either the ComposeEmailList command or ComposeEmailIndex command, which creates an email. The ComposeEmailList/ComposeEmailIndex command calls Model#saveComposedEmail(Email email), saving the email to EmailModel. In Figure 4.2.1.1, the user executes the ComposeEmailList command.

Step 2. Once the email is saved in the EmailModel, the ModelManager raises an EmailSavedEvent, to indicate that a new email is saved to the EmailModel.

Step 3. The EmailSavedEvent goes to the EventsCenter, and is then handled by StorageManager#handleEmailSavedEvent (EmailSavedEvent event), which then calls EmailDirStorage#saveEmail(EmailModel email). This saves the email to a specified local directory.

4.2.2. Design Considerations

Aspect: Method to create emails

Alternative 1 (current choice): Use Simple Java Mail.
- Pros: Simple Java Mail contains various methods to conveniently create emails. The library is easy to understand so any new developer can easily extend the current features.
- Cons: The design of created emails is limited to the Simple Java Mail API.
Alternative 2: Write a custom email builder.
- Pros: The design of created emails can be freely manipulated.
- Cons: Much more code has to be written.

Aspect: Text type

Alternative 1 (current choice): HTML text
- Pros: Users with HTML knowledge can manipulate the content of the email.
- Cons: Users unfamiliar with HTML minimally has to learn how the <br> tag works.
Alternative 2: Plain text
- Pros: Plain text is easily understood by almost any user.
- Cons: The design of the email content is very limited.

4.3. Calendar feature

4.3.1. Current Implementation

The calendar feature in Hallper is implemented using a third-party dependency, iCal4j. It creates .ics files and saves them onto the local computer. Calendars in Hallper are created as monthly calendars, a Map<Year, Set<Month>> in CalendarModel keeps a record of existing calendars in Hallper. It implements the following commands:

create_calendar — Creates a monthly calendar and stores it in local memory.
add_all_day_event — Adds an all day event into the monthly calendar specified.
add_event — Adds an event of a specified time frame into the monthly calendar.
delete_event — Deletes an existing event in the monthly calendar.
view_calendar — Loads a monthly calendar from local memory onto the Hallper.

Create_Calendar Command

This command is facilitated by CalendarModel and IcsCalendarStorage. It implements the following operations:

CalendarModel#createCalendar(Year year, Month month) — Initializes a calendar object in the CalendarModel.
CalendarModel#isExistingCalendar(Year year, Month month) — Checks if the calendar already exists in Hallper.
IcsCalendarStorage#createCalendar(Calendar calendar, String calendarName) — Saves the calendar passed from CalendarModel to the computer.

These operations are exposed in the Model interface as Model#createCalendar(Year year, Month month), Model#isExistingCalendar(Year year, Month month) and in the Storage interface as Storage#createCalendar(Calendar calendar, String calendarName) respectively.

Given below is an example usage scenario and how the create_calendar command behaves at each step:

Step 1. The user executes the create_calendar command by specifying the month and year. The create_calendar command then calls Model#isExistingCalendar(Year year, Month month), to check whether the calendar already exists inside Hallper. If it exists, the command does nothing and reflects to the user that the calendar already exists. Else, the command calls Model#createCalendar(Year year, Month month), initializing a calendar object inside CalendarModel.

Step 2. Once the calendar object is initialized in the CalendarModel, the ModelManager raises a CalendarCreatedEvent, to indicate that a calendar object has been initialized in the CalendarModel.

Step 3. The CalendarCreatedEvent goes to the EventsCenter, and is then handled by StorageManager#handleCalendarCreatedEvent(CalendarCreatedEvent event), which then calls IcsCalendarStorage#createCalendar(Calendar calendar, String calendarName). This saves the calendar to a specified local directory.

The following sequence diagram shows how the create_calendar operation works:

Figure 4.3.1.1: Sequence diagram for create_calendar command

Add Event Commands

The add_all_day_event and add_event command have many similarities, they differ only by their parameters and the number of checks called to verify the validity of the event to be added. Events in Hallper are created as VEvent objects as implemented in the iCal4j library. Both commands are facilitated by ModelManager, CalendarModel and IcsCalendarStorage. It implements the following operations:

ModelManager#loadCalendar(Year year, Month month) — Raises a LoadCalendarEvent.
CalendarModel#createAllDayEvent(Year year, Month month, int date, String title) — Creates an all day event object and saves it inside the loaded calendar in CalendarModel.
CalendarModel#createEvent(Year year, Month month, int startDate, int startHour, int startMin, int endDate, int endHour, int endMin, String title) — Creates an event object with the specified time frame and saves it inside the loaded calendar in CalendarModel.
CalendarModel#loadCalendar(Year year, Month month) — Loads the monthly calendar specified into CalendarModel.
CalendarModel#isExistingCalendar(Year year, Month month) — Checks if the calendar already exists in Hallper.
CalendarModel#isValidDate(Year year, Month month, int date) — Checks if the date is a valid date in accordance to the Gregorian calendar.
CalendarModel#isValidTime(int hour, int min) — Checks if the hour and minutes are valid in accordance to the 24 hour format.
CalendarModel#isValidTimeFrame(int startDate, int startHour, int startMin, int endDate, int endHour, int endMin) — Checks that the end date and time doesn’t occur before the start date and time.
IcsCalendarStorage#loadCalendar(String calendarName) — Loads the specified calendar from the local directory into local memory.
IcsCalendarStorage#createCalendar(Calendar calendar, String calendarName) — Saves the calendar passed from CalendarModel to the local directory.

These operations are exposed in the Model and Storage interface as :

Model#createAllDayEvent(Year year, Month month, int date, String title)
Model#createEvent(Year year, Month month, int startDate, int startHour, int startMin, int endDate, int endHour, int endMin, String title)
Model#loadCalendar(Year year, Month month)
Model#isExistingCalendar(Year year, Month month)
Model#isValidDate(Year year, Month month, int date)
Model#isValidTime(int hour, int min)
Model#isValidTimeFrame(int startDate, int startHour, int startMin, int endDate, int endHour, int endMin)
Storage#loadCalendar(String calendarName)
Storage#createCalendar(Calendar calendar, String calendarName)

Add_All_Day_Event Command

Given below is an example usage scenario and how the add_all_day_event command behaves at each step:

Step 1. The user executes the add_all_day_event command by specifying the month, year, date and title. The add_all_day_event command then calls Model#isExistingCalendar(Year year, Month month), Model#isValidDate(Year year, Month month, int date), to perform checks on whether the request to create event is valid. If it fails any one of the checks, the command does nothing and reflects to the user that the request to create event is not valid.

Step 2. Else if the calendar hasn’t been loaded yet, Model first calls CalendarModel#loadCalendar(Year year, Month month) to load the calendar into CalendarModel.

Step 3. Once the calendar object is loaded in the CalendarModel, it then calls Model#createAllDayEvent(Year year, Month month, int date, String title), which calls CalendarModel#createAllDayEvent(Year year, Month month, int date, String title). This creates an event object and loads it with all the relevant information.

Step 4. The ModelManager then raises a AllDayEventAddedEvent, to indicate an all day event has been created in the CalendarModel.

Step 5. The AllDayEventAddedEvent goes to the EventsCenter, and is then handled by StorageManager#handleAllDayEventAddedEvent(AllDayEventAddedEvent event), which then calls IcsCalendarStorage#createCalendar(Calendar calendar, String calendarName). This saves the updated calendar back to the local directory.

The following sequence diagram shows how the add_all_day_event operation works:

Figure 4.3.1.2: Sequence diagram for add_all_day_event command

Add_Event Command

Given below is an example usage scenario and how the add_event command behaves at each step:

Step 1. The user executes the add_event command by specifying the month, year, starting date, starting time, ending date, ending time and title. The add_event command then calls Model#isExistingCalendar(Year year, Month month), Model#isValidDate(Year year, Month month, int date), Model#isValidTime(int hour, int min) and Model#isValidTimeFrame(int startDate, int startHour, int startMin, int endDate, int endHour, int endMin) to perform checks on whether the request to create event is valid. If it fails any one of the checks, the command does nothing and reflects to the user that the request to create event is not valid.

Step 2. Else if the calendar hasn’t been loaded yet, Model first calls ModelManager#loadCalendar(Year year, Month month) to load the calendar into CalendarModel.

Step 3. Once the calendar object is loaded in the CalendarModel, it then calls Model#createEvent(Year year, Month month, int startDate, int startHour, int startMin, int endDate, int endHour, int endMin, String title), which calls CalendarModel#createEvent(Year year, Month month, int startDate, int startHour, int startMin, int endDate, int endHour, int endMin, String title). This creates an event object and loads it with all the relevant information.

Step 4. The ModelManager then raises a CalendarEventAddedEvent, to indicate an event with a specified time frame has been created in the CalendarModel.

Step 5. The CalendarEventAddedEvent goes to the EventsCenter, and is then handled by StorageManager#handleCalendarEventAddedEvent(CalendarEventAddedEvent event), which then calls IcsCalendarStorage#createCalendar(Calendar calendar, String calendarName). This saves the updated calendar back to the local directory.

The following sequence diagram shows how the add_event operation works:

Figure 4.3.1.3: Sequence diagram for add_event command

Delete_Event Command

This command is facilitated by ModelManager, CalendarModel and IcsCalendarStorage. It implements the following operations:

ModelManager#loadCalendar(Year year, Month month) — Raises a LoadCalendarEvent.
CalendarModel#loadCalendar(Year year, Month month) — Loads the monthly calendar specified into CalendarModel.
CalendarModel#deleteEvent(Year year, Month month) — Deletes an existing event in the monthly calendar.
CalendarModel#retrieveEvent(int startDate, int endDate, String title) — Retrieves the event object from the calendar.
CalendarModel#isSameEvent(int startDate, int endDate, String title, VEvent event) — Checks whether the requested event to be deleted is the same event object in the calendar.
CalendarModel#isExistingCalendar(Year year, Month month) — Checks if the calendar already exists in Hallper.
CalendarModel#isValidDate(Year year, Month month, int date) — Checks if the date is a valid date in accordance to the Gregorian calendar.
CalendarModel#isExistingEvent(Year year, Month month, int startDate, int endDate, String title) — Checks if an event exists in the monthly calendar.
IcsCalendarStorage#loadCalendar(String calendarName) — Loads the specified calendar from the local directory into local memory.
IcsCalendarStorage#createCalendar(Calendar calendar, String calendarName) — Saves the calendar passed from CalendarModel to the local directory.

These operations are exposed in the Model and Storage interface as :

Model#loadCalendar(Year year, Month month)
Model#deleteEvent(Year year, Month month, int startDate, int endDate, String title)
Model#isExistingCalendar(Year year, Month month)
Model#isValidDate(Year year, Month month, int date)
Model#isExistingEvent(Year year, Month month, int startDate, int endDate, String title)
Storage#loadCalendar(String calendarName)
Storage#createCalendar(Calendar calendar, String calendarName)

Given below is an example usage scenario and how the delete_event command behaves at each step:

Step 1. The user executes the delete_event command by specifying the month, year, starting date, ending date, and title. The delete_event command then calls Model#isExistingCalendar(Year year, Month month), Model#isValidDate(Year year, Month month, int date) and Model#isExistingEvent(Year year, Month month, int startDate, int endDate, String title) to perform checks on whether the request to delete event is valid. If it fails any one of the checks, the command does nothing and reflects to the user that the request to delete event is not valid. Else, the Model#isExistingEvent check will retrieve the event and load it inside the CalendarModel. It then calls Model#deleteEvent(Year year, Month month, int startDate, int endDate, String title).

Step 2. The Model#isExistingEvent check first calls ModelManager#loadCalendar(Year year, Month month) to load the calendar into CalendarModel. Once the calendar object is loaded in the CalendarModel, it then calls CalendarModel#retrieveEvent(int startDate, int endDate, String title) to retrieve the event and store it inside the CalendarModel as event to be deleted.

Step 3. The call to Model#deleteEvent(Year year, Month month, int startDate, int endDate, String title) calls CalendarModel#deleteEvent(Year year, Month month) which removes the event to be deleted in CalendarModel from the monthly calendar.

Step 4. The ModelManager then raises a CalendarEventDeletedEvent, to indicate an event has been deleted in the CalendarModel.

Step 5. The CalendarEventDeletedEvent goes to the EventsCenter, and is then handled by StorageManager#handleCalendarEventDeletedEvent(CalendarEventDeletedEvent event), which then calls IcsCalendarStorage#createCalendar(Calendar calendar, String calendarName). This saves the updated calendar back to the local directory.

The following sequence diagram shows how the delete_event operation works:

Figure 4.3.1.4: Sequence diagram for delete_event command

View_Calendar Command

This command is facilitated by ModelManager, CalendarModel and IcsCalendarStorage. It implements the following operations:

ModelManager#loadCalendar(Year year, Month month) — Raises a LoadCalendarEvent.
CalendarModel#isExistingCalendar(Year year, Month month) — Checks if the calendar already exists in Hallper.
IcsCalendarStorage#loadCalendar(String calendarName) — Loads the calendar from the computer.

These operations are exposed in the Model interface as Model#loadCalendar(Year year, Month month), Model#isExistingCalendar(Year year, Month month) and in the Storage interface as Storage#loadCalendar(String calendarName) respectively.

Given below is an example usage scenario and how the view_calendar command behaves at each step:

Step 1. The user executes the view_calendar command by specifying the month and year. The view_calendar command then calls Model#isExistingCalendar(Year year, Month month), to check whether the calendar already exists inside Hallper. If it exists, the command does nothing and reflects to the user that the calendar already exists. Else, the command calls Model#loadCalendar(Year year, Month month) which then raise a LoadCalendarEvent.

Step 2. The LoadCalendarEvent goes to the EventsCenter, and is then handled by StorageManager#handleLoadCalendarEvent(LoadCalendarEvent event), which then calls IcsCalendarStorage#loadCalendar(String calendarName). This loads the calendar from the specified local directory.

Step 3. Once the calendar is loaded, it then raise a CalendarLoadedEvent. The event goes to the EventsCenter, and is then handled by ModelManager#handleCalendarLoadedEvent(CalendarLoadedEvent event) which then calls CalendarModel#loadCalendar(Calendar calendar, String calendarName). This saves the calendar into the model.

The following sequence diagram shows how the view_calendar operation works:

Figure 4.3.1.5: Sequence diagram for view_calendar command

The following activity diagram summarizes what happens when a user executes a calendar command:

Figure 4.3.1.6: Activity diagram for calendar commands

4.3.2. Design Considerations

Aspect: File format

Pro: The .ics file format is compliant with the RFC 5545 format, which is industry recognised, and can be opened and viewed using many applications, including Microsoft Outlook, Google Calendar, and Apple Calendar.
Con: .ics file alone is not very useful. User needs to import the events created into users' preferred calender application manually and consistently. More implementations will be required to make .ics files useful in Hallper.

Aspect: Using iCal4j

iCal4j contains various methods that make creating, parsing and editing .ics files convenient. The library is widely used and easy to understand so any new developer can easily extend the current features.

4.4. Budget feature

4.4.1. Current Implementation

The budget feature in Hallper is implemented with reference to AddressBook. It stores Cca instead of Person, and each Cca contains the Name of the head and vice-head, Budget allocated, Spent and Outstanding and a set of transaction Entries. Each Entry contains a Date, Amount and Remarks. The budget feature is facilitated by BudgetBook and BudgetBookStorage, and can also read and write onto the ccabook.xml, just like the AddressBook. The purpose of this budget feature is to keep track of each Cca transaction.

It implements the following commands:

create — Creates a CCA with a given budget.
delete_cca — Deletes a specified CCA.
update — Updates the details of a specified CCA.
add_trans — Adds a transaction entry to a specified CCA.
delete_trans — Deletes a transaction entry to a specified CCA.
budget — Shows the transaction information of each CCA.

However, only the implementation of create, update, add_trans and budget will be discussed.

Create Command

The create mechanism is facilitated by BudgetBook and BudgetBookStorage. When a CCA is created, it is stored in a UniqueCcaList in the BudgetBook, and in a .xml file in the local directory. It implements the following command:

BudgetBook#addCca(Cca toAdd) — Adds a non existing CCA into the BudgetBook in Model.
BudgetBook#commitBudgetBook() — Saves a current version of the budget book in the VersionedBudgetBook.

These operations are exposed in the Model interface as:

Model#addCca(Cca cca)
Model#hasCca(CcaName name)
Model#hasCca(Cca cca)
Model#commitBudgetBook()

Given below is an example usage scenario and how the create cca mechanism behaves at each step.

Step 1. The user creates a new CCA by including the CCA name and the budget allocated to the CCA.

Step 2. create command checks for existing CCA name using BudgetBook#hasCca(Cca toAdd). If a CCA with the same name exists, the CCA is not created. Otherwise, it is added into the BudgetBook in the Model.

Step 3. BudgetBook#addCca(Cca cca) then invokes ModelManger#indicateBudgetBookChange() to raise a BudgetBookChangedEvent, which is handled by EventsCenter.

Step 4. BudgetBookChangedEvent is then handled by StorageManager#handleBudgetBookChangedEvent(BudgetBookChangedEvent event). StorageManager#saveBudgetBook(ReadOnlyBudgetBook data) is then called to update the existing ccabook.xml file with the new CCA.

The following sequence diagram shows how the create operation works:

Figure 4.4.1.1: Sequence diagram for create command

Update Command

The update mechanism is facilitated by BudgetBook and BudgetBookStorage. When a CCA is getting updated, it looks up the BudgetBook in the BudgetBookStorage of the Model for the CCA to update. It then updates the Cca stored inside the ccabook.xml file in the local directory. It implements the following commands:

BudgetBook#updateCca(Cca targetCca, Cca editedCca) — Updates an existing CCA in the BudgetBook in Model.
BudgetBook#commitBudgetBook() — Saves a current version of the budget book in the VersionedBudgetBook.
UpdateCommand#createEditedCca(Cca ccaToEdit, EditCcaDescriptor editCcaDescriptor) — Creates an updated version of the target CCA.
TransactionMath#updateDetails(Cca cca) — Updates the Spent and Outstanding amount of the specified CCA.

These operations are exposed in the Model interface as:

Model#updateCca(Cca targetCca, Cca editedCca)
Model#hasCca(CcaName cca)
Model#commitBudgetBook()
Model#hasPerson(Name person)

Given below is an example usage scenario and how the update cca mechanism behaves at each step:

Step 1. The user specifies the CCA to be updated by including the CCA name and the fields to update.

Step 2. The user can update the head’s name, the vice-head’s name, the budget allocated, and the details of a transaction entry such as its date, amount involved and remarks for the transaction. These information is stored in the UpdateCommand#EditCcaDescriptor. Any fields that are not valid will display an error message.

Step 3. update command then checks for existing CCA name using BudgetBook#hasCca(CcaName ccaName). If the cca name does not exist, an error message will appear. Otherwise, the updated CCA will be created from the UpdateCommand#EditCcaDescriptor using UpdateCommand#createEditedCca(Cca ccaToEdit, EditCcaDescriptor editCcaDescriptor).

Step 4. BudgetBook#updateCca(Cca targetCca, Cca editedCca) then replaces the existing CCA with the updated CCA and invokes ModelManger#indicateBudgetBookChange() to raise a BudgetBookChangedEvent, which is handled by EventsCenter.

Step 5. BudgetBookChangedEvent is handled by StorageManager#handleBudgetBookChangedEvent(BudgetBookChangedEvent event). StorageManager#saveBudgetBook(ReadOnlyBudgetBook data) is then called to replace the specified CCA in the the existing ccabook.xml with the updated CCA and its information.

The following sequence diagram shows how the update operation works:

Figure 4.4.1.2: Sequence diagram for update command

Add_Transaction Command

The add_trans mechanism is facilitated by BudgetBook and BudgetBookStorage. When a transaction entry is to be added, it looks up the BudgetBook in the BudgetBookStorage of the Model for the CCA and add the specified entry to the CCA. It then updates the Cca stored inside the ccabook .xml file in the local directory. It implements the following commands:

BudgetBook#updateCca(Cca targetCca, Cca editedCca) — Updates an existing CCA in the BudgetBook in Model.
BudgetBook#commitBudgetBook() — Saves a current version of the budget book in the VersionedBudgetBook.
TransactionMath#updateDetails(Cca cca) — Updates the Spent and Outstanding amount of the specified CCA.

These operations are exposed in the Model interface as:

Model#updateCca(Cca targetCca, Cca editedCca)
Model#hasCca(CcaName cca)
Model#commitBudgetBook()

Given below is an example usage scenario and how the add transaction mechanism behaves at each step:

Step 1. The user specifies the CCA to add transaction to by including the CCA name and the transaction fields.

Step 2. The user must include the Date, Amount and Remarks for the transaction entry. Any fields that are not valid will display an error message.

Step 3. add_trans command then checks for existing CCA name using BudgetBook#hasCca(CcaName ccaName). If the cca name does not exist, an error message will appear. Otherwise, the Entry is created and is added to the target Cca using Cca#AddNewTransaction(Entry entry).

Step 4. The Spent and Outstanding is then updated using TransactionMath#updateDetails(Cca cca).

Step 5. BudgetBook#updateCca(Cca targetCca, Cca editedCca) then replaces the existing CCA with the updated CCA and invokes ModelManger#indicateBudgetBookChange() to raise a BudgetBookChangedEvent, which is handled by EventsCenter.

Step 6. BudgetBookChangedEvent is handled by StorageManager#handleBudgetBookChangedEvent(BudgetBookChangedEvent event). StorageManager#saveBudgetBook(ReadOnlyBudgetBook data) is then called to replace the specified CCA in the the existing ccabook.xml with the updated CCA and its transaction entry.

The following sequence diagram shows how the add transaction operation works:

_Figure 4.4.1.3: Sequence diagram for add_trans command

Budget Command

The budget mechanism is facilitated by BudgetBook and BudgetBookStorage. It opens up a separate window to display the CCA information and its transaction history. It implements the following command:

`EventsCenter#getInstance() — Gets the instance of the EventsCenter.
`EventsCenter#post(E event) — Posts an event to the event bus.

Given below is an example usage scenario and how the budget mechanism behaves at each step.

Step 1. The user enters the budget command with or without a specified CCA.

Step 2. When a CCA is specified, BudgetCommand(CcaName ccaName) is called. Otherwise, BudgetCommand() is called and the CcaName is null.

Step 3. If the CCA is specified, the budget command checks whether the CCA specified exist.

Step 4. budget command then raises a ShowBudgetViewEvent, which is handled by EventsCenter.

Step 5. ShowBudgetViewEvent is handled by MainWindow#handleShowBudgetEvent(ShowBudgetViewEvent event) and invokes MainWindow#handleBudget(CcaName ccaName). This opens the budget window through BudgetWindow#show(CcaName ccaName).

Step 6. It then checks whether the CCA name is present in BudgetWindow#fillInnerParts(CcaName ccaName). If CCA name is present, BudgetBrowserPanel(ccaName) is called and the specified CCA information will be displayed. Otherwise, BudgetBrowserPanel() will be called and a blank page will be showed.

The following activity diagram summarizes what happens when a user executes a budget command:

Figure 4.4.1.4: Activity diagram for budget command

4.4.2. Design Considerations

Aspect: Choice of local storage format

Alternative 1 (current choice): Saves in .xml format.
- Pros: Easy to create, understand, move and translate into other environments. International data standard for storing information.
- Cons: Parsing XML software is slow and cumbersome. Uses large amounts of memory due to the verbosity and incurs cost of parsing large XML files.
Alternative 2: Save in .json format.
- Pros: Faster in parsing information as compared to .xml.
- Cons: JSON has no error handling. Therefore when the code fails to insert information, the code will not throw any error.

4.5. Clear feature

4.5.1. Current Implementation

The clear feature allows the user to clear persons associated with specified keywords from the database.

It implements the following operations: * ClearCommand#clearAll(Model model) — Clears the entire database. * ClearCommand#clearSpecific(Model model) — Clears persons associated with specified keywords.

These operations are exposed in the Model interface as Model#commitAddressBook, Model#resetData() and Model#clearMultiplePersons(List<Person> target).

Given below is an example usage scenario and how the clear mechanism behaves at each step:

Step 1. The user specifies CCA(s) and/or room(s) of persons to be cleared from the database.

Step 2. ClearCommandParser checks for the validity of the CCA(s) and/or room(s) specified. If non-existent argument(s) specified, a CommandException will be thrown. A combination of existing and non-existent arguments specified will be successfully parsed.

Step 3. ClearCommand#execute(Model model, CommandHistory history) is then called and invokes ClearCommand#clearSpecific(Model model), which uses the specified arguments to create a persons list containing associated persons to be cleared. ModelManager#clearMultiplePersons(List<Person> target) is then invoked to clear the internal list of persons in target.

Step 4. After the internal list is cleared, ModelManager#clearMultiplePersons(List<Person> target) then invokes ModelManager#indicateAddressBookChanged(), which raises an AddressBookChangedEvent which is handled by EventsCenter.

Step 5. AddressBookChangedEvent is then handled by StorageManager#handleAddressBookChangedEvent(AddressBookChangedEvent event). StorageManager#saveAddressBook(ReadOnlyAddressBook data) is then called to update the existing addressbook.xml file with the cleared persons list.

The following sequence diagram shows how the clear operation works:

Figure 4.5.1.1: Sequence diagram of clear command on specified keywords.

The following activity diagram summarizes what happens when a user executes the clear command:

Figure 4.5.1.2: Activity diagram showing different path flows of clear command.

4.5.2. Design Considerations

Aspect: Merging command to clear entire database or specific persons

Alternative 1 (current choice): Clear command is merged.
- Pros: Due to the similar function of clearing persons from the database, merging them under a single command makes it easier for the user to remember and produce the command input. Clearing of the entire database is also rarely executed so it makes logical sense to merge these commands.
- Cons: The user will not be able to use all as a CCA as it is a reserved keyword to clear the entire database.
Alternative 2: Clear commands are separated.
- Pros: The user can clearly distinguish between the two features by renaming them with different command inputs.
- Cons: There is no need for a separate command for clearing the entire database as it is a rarely used feature.

4.6. Erase Feature

4.6.1. Current Implementation

The erase feature allows the user to erase specified CCAs from persons associated with the CCAs in the database.

It implements the following operation:

EraseCommand#execute(Model model, CommandHistory history) — Executes the erasure of CCAs from persons in the database.

This operation is exposed in the Model interface as Model#commitAddressBook() and Model#removeTagsFromPersons(ArrayList<Person> target, ArrayList<Person> original).

Given below is an example usage scenario and how the erase mechanism behaves at each step:

Step 1. The user specifies CCA(s) to be erased from the database.

Step 2. EraseCommandParser checks for the validity of the CCA(s) specified. If non-existent CCA(s) specified, a CommandException will be thrown. A combination of existing and non-existent CCAs specified will be successfully parsed.

Step 3. EraseCommand#execute(Model model, CommandHistory history) is then called and uses the specified CCA arguments to create a new persons list with specified CCAs erased from associated persons. ModelManager#removeTagsFromPersons(List<Person> editedPersons, List<Person> targets) is then invoked to update the internal list with the new persons list.

Step 4. After the internal list is updated, ModelManager#removeTagsFromPersons(List<Person> editedPersons, List<Person> targets) then invokes ModelManager#indicateAddressBookChanged(), which raises an AddressBookChangedEvent which is handled by EventsCenter.

The following sequence diagram shows how the erase operation works:

Figure 4.6.1.1: Sequence diagram of erase command on specified keywords.

The following activity diagram summarizes what happens when a user executes the erase command:

Figure 4.6.1.2: Activity diagram showing different path flows of erase command.

4.6.2. Design Considerations

Aspect: Algorithm to identify persons associated with CCAs to be erased

Alternative 1 (current choice): Loop through current internal list to extract associated persons.
- Pros: The implementation of the extraction algorithm is straightforward and will not miss out any persons.
- Cons: The execution time will be slow for large quantity of persons in the internal list.
Alternative 2: Store persons in a multilayer linked list data structure.
- Pros: The number of CCAs are fewer than the number of persons in the database, so it would be faster to search for the target CCAs in the first layer of the linked list and obtain the entire second layer list of persons associated with the CCA.
- Cons: The implementation is rather complicated and requires other commands such as add, edit and delete to be modified as well. More space would be needed on the computer to store the multilayer linked list other than the actual addressbook.xml file.

4.7. Import feature

4.7.1. Current Implementation

The import feature allows .xml files of different formats to be imported from the computer.

It implements the following operations and classes:

ImportCommand#parseFile() — Parses specified path into document for reading.
ImportAddressBook#execute(Document doc, Model model) — Imports .xml file from the specified path to update Hallper data.
ImportCcaList#execute(Document doc, Model model) — Imports .xml file from the specified path to update Hallper contacts' CCAs.

These operations are exposed in the Model interface as Model#commitAddressBook(), Model#addMultiplePersons() and Model#updateMultiplePersons.

Given below is an example usage scenario and how the import mechanism behaves at each step.

Step 1. The user imports .xml file by specifying the path of the file.

Step 2. ImportCommandParser checks for the validity of the path and .xml file format. If .xml file has an invalid format, the specified file will not be imported.

Step 3. ImportCommand#parseFile() then prepares the file for reading by parsing into a document.

Step 4: ImportCommand#execute(Model model, CommandHistory history) then invokes ImportAddressBook#execute(Document doc, Model model) to read the document.

Step 5. After the document data is read, ImportAddressBook#execute(Document doc, Model model) then invokes ModelManager#addMultiplePersons(List<Person> personList) to update Hallper’s internal list and ModelManager#indicateAddressBookChanged(), which raises an AddressBookChangedEvent which is handled by EventsCenter.

Step 6. AddressBookChangedEvent is then handled by StorageManager#handleAddressBookChangedEvent(AddressBookChangedEvent event). StorageManager#saveAddressBook(ReadOnlyAddressBook data) is then called to update the existing addressbook.xml file with the new contacts.

The following sequence diagram shows how the import operation works:

Figure 4.7.1.1: Sequence diagram of import command.

The following activity diagram summarizes what happens when a user executes the import command:

Figure 4.7.1.2: Activity diagram showing different path flows of import command.

4.7.2. Design Considerations

Aspect: Choice of component to read imported file

Alternative 1 (current choice): Reads file in Logic.
- Pros: Easy to change parsing of .xml file when .xml file format changes. New .xml file formats can be added without disrupting the existing parsers.
- Cons: Importing from the computer is a storage-related feature but the reading of the file is located outside of Storage component.
Alternative 2: Reads file in Storage.
- Pros: Proper grouping of import implementation inside related component.
- Cons: More complicated implementation if more .xml file formats are added to be parsed in the future.

4.8. Export feature

4.8.1. Current Implementation

The export feature allows Hallper data to be exported as an xml file to the computer.

It implements the following operation:

ExportCommand#execute(Model model, CommandHistory history) — Exports current Hallper data as an xml file to the specified path.

This operation is exposed in the Model interface as Model#exportAddressBook(Path filePath).

Given below is an example usage scenario and how the export mechanism behaves at each step.

Step 1. The user exports an 'xml' file by specifying the destination path and name of the exported file.

Step 2. ExportCommandParser checks for the validity of the path and file name. If path or file name are invalid, Hallper data will not be exported. Otherwise, path and filename will be parsed into a single, full path.

Step 3. ExportCommand#execute(Model model, CommandHistory history) then invokes ModelManager#exportAddressBook(Path filePath) which raises an ExportAddressBookEvent.

Step 4. ExportAddressBookEvent is then handled by StorageManager#handleExportAddressBookEvent(ExportAddressBookEvent event). StorageManager#exportAddressBook(ReadOnlyAddressBook addressBook, Path path) is then called to export Hallper’s storage data to the specified path.

The following sequence diagram shows how the export operation works:

Figure 4.8.1.1: Sequence diagram of export command.

The following activity diagram summarizes what happens when a user executes the export command:

Figure 4.8.1.2: Activity diagram showing different path flows of export command.

4.8.2. Design Considerations

Aspect: Choice of export format

Alternative 1 (current choice): Export .xml format only.
- Pros: Easy for user to update and re-import the .xml file. Standardised format for Hallper-related data files.
- Cons: Difficult to convert/transfer data to other applications due to limited export format. Need to use external applications to convert .xml file.
Alternative 2: Export .xml, .txt and .xlsx formats.
- Pros: More options for user to export Hallper data. Exported files can be read across different applications.
- Cons: Unused file formats. .xml is the format that is mainly used by Hallper so .txt and .xlsx may be underused or unused.

4.9. Image feature

4.9.1. Current Implementation

The image feature allows .jpg image files to be uploaded into Hallper to a specific person from the computer. The feature is facilitated by ProfilePictureDirStorage. It implements the follow operations:

ProfilePictureDirStorage#readProfilePicture(File file) — Reads the file that is specified by the user through a path and returns a copy of the image that is being read.
ProfilePictureDirStorage#saveProfilePicture(BufferedImage image, Room number) — Saves the copied image into the computer.

Both operations are exposed in the Storage interface as Storage#readProfilePicture(File file) and Storage#saveProfilePicture(BufferedImage image, Room number) respectively.

Given below is an example usage scenario and how the image mechanism behaves at each step:

Step 1. The user specifies the file path of the .jpg image to be uploaded and the person’s room number.

Step 2. ImageCommandParser passes the room number and file that is specified by the file path to ImageCommand.

Step 3. ImageCommand searches Hallper for the person that is tagged with the specified room number. It returns an error message if the room number specified is not tagged to any person.

Step 4. Once the room number is verified, a NewImageEvent is raised from the ImageCommand to initiate the reading and copying of the image from the given file path.

Step 5. The NewImageEvent goes to the EventCenter, and is then handled by StorageManager#handleNewImageEvent(NewImageEvent event). ProfilePictureStorage#readProfilePicture(File file) is then called to read the image file. After reading a valid image file, the ProfilePictureStorage#saveProfilePicture(BufferedImage image, Room number) is called to save the image into the computer.

Step 6. Hallper then updates the person’s profile picture field with the name of the copied image.

The following sequence diagram shows how the image operation works:

Figure 4.7.1.1: Sequence diagram for image operation

The following activity diagram summarizes what happens when a user executes the image command:

Figure 4.7.1.2: Activity diagram for image operation

4.9.2. Design Considerations

Aspect: Choice of component to read and save the file

Alternative 1 (current choice): Read and save image file through Storage.
- Pro: Reading and saving files through Storage follows the architecture that the project is built upon.
- Con: Informing the user of invalid file path is much more complicated.
Alternative 2: Read and save image file through ImageCommand.
- Pro: Informing the user of invalid file path will be similar to when an invalid command is given.
- Con: Reading and saving the image file from ImageCommand breaks the architecture of the project.

4.9.3. Aspect: Image type

Alternative 1 (current choice): Only .jpg image files.
- Pro: Copying the image will be easier since all images saved will be in the form of .jpg.
- Con: Limiting users to only being able to upload one type of image file.
Alternative 2: Allow for multiple image file types i.e .jpg, .png.
- Pro: Increasing the valid image file types allows users to have more choices when choosing the picture to upload.
- Con: Copying of the image will be more complicated since all images will be saved as a .jpg image file type.

4.10. Search feature

4.10.1. Current Implementation

The search feature allows the user to search for persons who in Hallper using their room number, school and CCAs.

It implements the following operation:

SearchCommand#execute(Model model, CommandHistory history) — Updates the filtered persons list with persons that has fields that match any of the predicates.

This operation is exposed in the Model interface as Model#updateFilteredPersonList(Predicate<Person> predicate).

Given below is an example usage scenario and how the search mechanism behaves at each step.

Step 1. The user specifies the keywords to search Hallper with.

Step 2. SearchCommandParser checks for the keywords after the search command word. If there are no keywords after the search command word, a ParseException is thrown. Any keywords that comes after the search command word will be successfully parsed into a FieldsContainsKeywordsPredicate

Step 3. SearchCommand#execute(Model model, CommandHistory history) is then called and uses the predicate to update the filtered persons list.

Step 4. After updating the list, the PersonListPanel is then updated to display the search result.

The following sequence diagram shows how the search operation works:

Figure 4.10.1.1: Sequence diagram for search operation

The following activity diagram summarizes what happens when a user executes the search command:

Figure 4.10.1.2: Activity diagram for search operation

4.10.2. Design Considerations

Aspect: Fields to search

Alternative 1 (current choice): Limit choice to only room number, school and CCA.
- Pro: The search command will only search for the fields that are the most commonly used.
- Con: The fields that can be used as keywords are limited.
Alternative 2: Include all available fields to be the search criteria.
- Pro: Allows the command to search using more criteria.
- Con: Including name as a search criteria will overlap with the current find command and phone numbers are not commonly used as search criterias.

4.11. [Proposed] Data encryption

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

4.12. Logging

java.util.logging package is used for logging. The LogsCenter class is used to manage the logging levels and logging destinations.

Logging level can be controlled using the logLevel setting in the configuration file (See Section 4.13, “Configuration”)
The Logger for a class can be obtained using LogsCenter.getLogger(Class) which will log messages according to the specified logging level
Current log messages are output through: Console and to a .log file.

Logging Levels

SEVERE : Detect critical problem which may possibly cause the termination of the application.
WARNING : Able to continue, but with caution.
INFO : Show information on the noteworthy actions by the App.
FINE : Display eetails that is not usually noteworthy but may be useful in debugging e.g. print the actual list instead of just its size.

4.13. Configuration

Certain properties of the application can be controlled (e.g App name, logging level) through the configuration file (default: config.json).

5. Documentation

We use asciidoc for writing documentation.

We chose asciidoc over Markdown because asciidoc, although a bit more complex than Markdown, provides more flexibility in formatting.

5.1. Editing documentation

See UsingGradle.adoc to learn how to render .adoc files locally to preview the end result of your edits. Alternatively, you can download the AsciiDoc plugin for IntelliJ, which allows you to preview the changes you have made to your .adoc files in real-time.

5.2. Publishing documentation

See UsingTravis.adoc to learn how to deploy GitHub Pages using Travis.

5.3. Converting documentation to PDF format

We use Google Chrome for converting documentation to PDF format, as Chrome’s PDF engine preserves hyperlinks used in webpages.

Here are the steps to convert the project documentation files to PDF format.

Follow the instructions in UsingGradle.adoc to convert the AsciiDoc files in the docs/ directory to HTML format.
Go to your generated HTML files in the build/docs folder, right click on them and select Open with → Google Chrome.
Within Chrome, click on the Print option in Chrome’s menu.
Set the destination to Save as PDF, then click Save to save a copy of the file in PDF format. For best results, use the settings indicated in the screenshot below.

Figure 5.3.1: Saving documentation as PDF files in Chrome

5.4. Site-wide documentation settings

The build.gradle file specifies some project-specific asciidoc attributes which affects how all documentation files within this project are rendered.

Attributes left unset in the build.gradle file will use their default value, if any.

Table 5.4.1: List of site-wide attributes

Attribute name Description Default value

Attribute name	Description	Default value
`site-name`	The name of the website. If set, the name will be displayed near the top of the page.	not set
`site-githuburl`	URL to the site’s repository on GitHub. Setting this will add a "View on GitHub" link in the navigation bar.	not set
`site-seedu`	Define this attribute if the project is an official SE-EDU project. This will render the SE-EDU navigation bar at the top of the page, and add some SE-EDU-specific navigation items.	not set

site-name

The name of the website. If set, the name will be displayed near the top of the page.

not set

site-githuburl

URL to the site’s repository on GitHub. Setting this will add a "View on GitHub" link in the navigation bar.

not set

site-seedu

Define this attribute if the project is an official SE-EDU project. This will render the SE-EDU navigation bar at the top of the page, and add some SE-EDU-specific navigation items.

not set

5.5. Per-file documentation settings

Each .adoc file may also specify some file-specific asciidoc attributes which affects how the file is rendered.

Asciidoctor’s built-in attributes may be specified and used as well.

Attributes left unset in .adoc files will use their default value, if any.

Table 5.5.1: List of per-file attributes, excluding Asciidoctor’s built-in attributes

Attribute name Description Default value

Attribute name	Description	Default value
`site-section`	Site section that the document belongs to. This will cause the associated item in the navigation bar to be highlighted. One of: `UserGuide`, `DeveloperGuide`, `LearningOutcomes`, `AboutUs`, `ContactUs` Official SE-EDU projects only	not set
`no-site-header`	Set this attribute to remove the site navigation bar.	not set

site-section

Site section that the document belongs to. This will cause the associated item in the navigation bar to be highlighted. One of: UserGuide, DeveloperGuide, LearningOutcomes*, AboutUs, ContactUs

* Official SE-EDU projects only

not set

no-site-header

Set this attribute to remove the site navigation bar.

not set

5.6. Site template

The files in docs/stylesheets are the CSS stylesheets of the site. You can modify them to change some properties of the site’s design.

The files in docs/templates controls the rendering of .adoc files into HTML5. These template files are written in a mixture of Ruby and Slim.

Modifying the template files in docs/templates requires some knowledge and experience with Ruby and Asciidoctor’s API. You should only modify them if you need greater control over the site’s layout than what stylesheets can provide. The SE-EDU team does not provide support for modified template files.

6. Testing

Testing is a crucial part of developing your application. Testing allows you to verify the correctness and usability of your app, before releasing it to users.

6.1. Running tests

There are three ways to run tests.

The most reliable way to run tests is the 3rd one. The first two methods might fail some GUI tests due to platform/resolution-specific idiosyncrasies.

Method 1: Using IntelliJ JUnit test runner

To run all tests, right-click on the src/test/java folder and choose Run 'All Tests'
To run a subset of tests, you can right-click on a test package, test class, or a test and choose Run 'ABC'

Method 2: Using Gradle

Open a console and run the command gradlew clean allTests (Mac/Linux: ./gradlew clean allTests)

See UsingGradle.adoc for more info on how to run tests using Gradle.

Method 3: Using Gradle (headless)

Thanks to the TestFX library we use, our GUI tests can be run in the headless mode. In the headless mode, GUI tests do not show up on the screen. That means the developer can do other things on the Computer while the tests are running.

To run tests in headless mode, open a console and run the command gradlew clean headless allTests (Mac/Linux: ./gradlew clean headless allTests)

6.2. Types of tests

We have two types of tests:

GUI Tests - These are tests involving the GUI. They include,
1. System Tests that test the entire App by simulating user actions on the GUI. These are in the systemtests package.
2. Unit tests that test the individual components. These are in seedu.address.ui package.
Non-GUI Tests - These are tests not involving the GUI. They include,
1. Unit tests targeting the lowest level methods/classes.
  e.g. seedu.address.commons.StringUtilTest
2. Integration tests that are checking the integration of multiple code units (those code units are assumed to be working).
  e.g. seedu.address.storage.StorageManagerTest
3. Hybrids of unit and integration tests. These test are checking multiple code units as well as how the are connected together.
  e.g. seedu.address.logic.LogicManagerTest

6.3. Troubleshooting testing

Problem: HelpWindowTest fails with a NullPointerException.

Reason: One of its dependencies, HelpWindow.html in src/main/resources/docs is missing.
Solution: Execute Gradle task processResources.

7. Dev Ops

This section describes the tools used for building, testing, and releasing the application.

7.1. Build automation

See UsingGradle.adoc to learn how to use Gradle for build automation.

7.2. Continuous integration

We use Travis CI and AppVeyor to perform Continuous Integration on our projects. See UsingTravis.adoc and UsingAppVeyor.adoc for more details.

7.3. Coverage reporting

We use Coveralls to track the code coverage of our projects. See UsingCoveralls.adoc for more details.

7.4. Documentation previews

When a pull request has changes to asciidoc files, you can use Netlify to see a preview of how the HTML version of those asciidoc files will look like when the pull request is merged. See UsingNetlify.adoc for more details.

7.5. Making a release

Here are the steps to create a new release.

Update the version number in MainApp.java.
Generate a JAR file using Gradle.
Tag the repo with the version number. e.g. v0.1
Create a new release using GitHub and upload the JAR file you created.

7.6. Managing dependencies

A project often depends on third-party libraries. For example, Address Book depends on the Jackson library for XML parsing. Managing these dependencies can be automated using Gradle. For example, Gradle can download the dependencies automatically, which is better than these alternatives.
a. Include those libraries in the repo (this bloats the repo size)
b. Require developers to download those libraries manually (this creates extra work for developers)

Appendix A: Suggested Programming Tasks to Get Started

Suggested path for new programmers:

First, add small local-impact (i.e. the impact of the change does not go beyond the component) enhancements to one component at a time. Some suggestions are given in Section A.1, “Improving each component”.
Next, add a feature that touches multiple components to learn how to implement an end-to-end feature across all components. Section A.2, “Creating a new command: remark” explains how to go about adding such a feature.

A.1. Improving each component

Each individual exercise in this section is component-based (i.e. you would not need to modify the other components to get it to work).

`Logic` component

Scenario: You are in charge of logic. During dog-fooding, your team realize that it is troublesome for the user to type the whole command in order to execute a command. Your team devise some strategies to help cut down the amount of typing necessary, and one of the suggestions was to implement aliases for the command words. Your job is to implement such aliases.

Do take a look at Section 3.3, “Logic component” before attempting to modify the Logic component.

Add a shorthand equivalent alias for each of the individual commands. For example, besides typing clear, the user can also type c to remove all persons in the list.
- Hints
  
  Just like we store each individual command word constant COMMAND_WORD inside *Command.java (e.g. FindCommand#COMMAND_WORD, DeleteCommand#COMMAND_WORD), you need a new constant for aliases as well (e.g. FindCommand#COMMAND_ALIAS).
  
  AddressBookParser is responsible for analyzing command words.
- Solution
  
  Modify the switch statement in AddressBookParser#parseCommand(String) such that both the proper command word and alias can be used to execute the same intended command.
  
  Add new tests for each of the aliases that you have added.
  
  Update the user guide to document the new aliases.
  
  See this PR for the full solution.

`Model` component

Scenario: You are in charge of model. One day, the logic-in-charge approaches you for help. He wants to implement a command such that the user is able to remove a particular tag from everyone in the address book, but the model API does not support such a functionality at the moment. Your job is to implement an API method, so that your teammate can use your API to implement his command.

Do take a look at Section 3.4, “Model component” before attempting to modify the Model component.

Add a removeTag(Tag) method. The specified tag will be removed from everyone in the address book.
- Hints
  
  The Model and the AddressBook API need to be updated.
  
  Think about how you can use SLAP to design the method. Where should we place the main logic of deleting tags?
  
  Find out which of the existing API methods in AddressBook and Person classes can be used to implement the tag removal logic. AddressBook allows you to update a person, and Person allows you to update the tags.
- Solution
  
  Implement a removeTag(Tag) method in AddressBook. Loop through each person, and remove the tag from each person.
  
  Add a new API method deleteTag(Tag) in ModelManager. Your ModelManager should call AddressBook#removeTag(Tag).
  
  Add new tests for each of the new public methods that you have added.
  
  See this PR for the full solution.

`Ui` component

Scenario: You are in charge of ui. During a beta testing session, your team is observing how the users use your address book application. You realize that one of the users occasionally tries to delete non-existent tags from a contact, because the tags all look the same visually, and the user got confused. Another user made a typing mistake in his command, but did not realize he had done so because the error message wasn’t prominent enough. A third user keeps scrolling down the list, because he keeps forgetting the index of the last person in the list. Your job is to implement improvements to the UI to solve all these problems.

Do take a look at Section 3.2, “UI component” before attempting to modify the UI component.

Use different colors for different tags inside person cards. For example, friends tags can be all in brown, and colleagues tags can be all in yellow.

Before

After
- Hints
  
  The tag labels are created inside the PersonCard constructor (new Label(tag.tagName)). JavaFX’s Label class allows you to modify the style of each Label, such as changing its color.
  
  Use the .css attribute -fx-background-color to add a color.
  
  You may wish to modify DarkTheme.css to include some pre-defined colors using css, especially if you have experience with web-based css.
- Solution
  
  You can modify the existing test methods for PersonCard 's to include testing the tag’s color as well.
  
  See this PR for the full solution.
  
  The PR uses the hash code of the tag names to generate a color. This is deliberately designed to ensure consistent colors each time the application runs. You may wish to expand on this design to include additional features, such as allowing users to set their own tag colors, and directly saving the colors to storage, so that tags retain their colors even if the hash code algorithm changes.
Modify NewResultAvailableEvent such that ResultDisplay can show a different style on error (currently it shows the same regardless of errors).

Before

After
- Hints
  
  NewResultAvailableEvent is raised by CommandBox which also knows whether the result is a success or failure, and is caught by ResultDisplay which is where we want to change the style to.
  
  Refer to CommandBox for an example on how to display an error.
- Solution
  
  Modify NewResultAvailableEvent 's constructor so that users of the event can indicate whether an error has occurred.
  
  Modify ResultDisplay#handleNewResultAvailableEvent(NewResultAvailableEvent) to react to this event appropriately.
  
  You can write two different kinds of tests to ensure that the functionality works:
  
  The unit tests for ResultDisplay can be modified to include verification of the color.
  
  The system tests AddressBookSystemTest#assertCommandBoxShowsDefaultStyle() and AddressBookSystemTest#assertCommandBoxShowsErrorStyle() to include verification for ResultDisplay as well.
  
  See this PR for the full solution.
  
  Do read the commits one at a time if you feel overwhelmed.
Modify the StatusBarFooter to show the total number of people in the address book.

Before

After
- Hints
  
  StatusBarFooter.fxml will need a new StatusBar. Be sure to set the GridPane.columnIndex properly for each StatusBar to avoid misalignment!
  
  StatusBarFooter needs to initialize the status bar on application start, and to update it accordingly whenever the address book is updated.
- Solution
  
  Modify the constructor of StatusBarFooter to take in the number of persons when the application just started.
  
  Use StatusBarFooter#handleAddressBookChangedEvent(AddressBookChangedEvent) to update the number of persons whenever there are new changes to the addressbook.
  
  For tests, modify StatusBarFooterHandle by adding a state-saving functionality for the total number of people status, just like what we did for save location and sync status.
  
  For system tests, modify AddressBookSystemTest to also verify the new total number of persons status bar.
  
  See this PR for the full solution.

`Storage` component

Scenario: You are in charge of storage. For your next project milestone, your team plans to implement a new feature of saving the address book to the cloud. However, the current implementation of the application constantly saves the address book after the execution of each command, which is not ideal if the user is working on limited internet connection. Your team decided that the application should instead save the changes to a temporary local backup file first, and only upload to the cloud after the user closes the application. Your job is to implement a backup API for the address book storage.

Do take a look at Section 3.5, “Storage component” before attempting to modify the Storage component.

Add a new method backupAddressBook(ReadOnlyAddressBook), so that the address book can be saved in a fixed temporary location.
- Hint
  
  Add the API method in AddressBookStorage interface.
  
  Implement the logic in StorageManager and XmlAddressBookStorage class.
- Solution
  
  See this PR for the full solution.

A.2. Creating a new command: `remark`

By creating this command, you will get a chance to learn how to implement a feature end-to-end, touching all major components of the app.

Scenario: You are a software maintainer for addressbook, as the former developer team has moved on to new projects. The current users of your application have a list of new feature requests that they hope the software will eventually have. The most popular request is to allow adding additional comments/notes about a particular contact, by providing a flexible remark field for each contact, rather than relying on tags alone. After designing the specification for the remark command, you are convinced that this feature is worth implementing. Your job is to implement the remark command.

A.2.1. Description

Edits the remark for a person specified in the INDEX.
Format: remark INDEX r/[REMARK]

Examples:

remark 1 r/Likes to drink coffee.
Edits the remark for the first person to Likes to drink coffee.
remark 1 r/
Removes the remark for the first person.

A.2.2. Step-by-step Instructions

[Step 1] Logic: Teach the app to accept 'remark' which does nothing

Let’s start by teaching the application how to parse a remark command. We will add the logic of remark later.

Main:

Add a RemarkCommand that extends Command. Upon execution, it should just throw an Exception.
Modify AddressBookParser to accept a RemarkCommand.

Tests:

Add RemarkCommandTest that tests that execute() throws an Exception.
Add new test method to AddressBookParserTest, which tests that typing "remark" returns an instance of RemarkCommand.

[Step 2] Logic: Teach the app to accept 'remark' arguments

Let’s teach the application to parse arguments that our remark command will accept. E.g. 1 r/Likes to drink coffee.

Main:

Modify RemarkCommand to take in an Index and String and print those two parameters as the error message.
Add RemarkCommandParser that knows how to parse two arguments, one index and one with prefix 'r/'.
Modify AddressBookParser to use the newly implemented RemarkCommandParser.

Tests:

Modify RemarkCommandTest to test the RemarkCommand#equals() method.
Add RemarkCommandParserTest that tests different boundary values for RemarkCommandParser.
Modify AddressBookParserTest to test that the correct command is generated according to the user input.

[Step 3] Ui: Add a placeholder for remark in `PersonCard`

Let’s add a placeholder on all our PersonCard s to display a remark for each person later.

Main:

Add a Label with any random text inside PersonListCard.fxml.
Add FXML annotation in PersonCard to tie the variable to the actual label.

Tests:

Modify PersonCardHandle so that future tests can read the contents of the remark label.

[Step 4] Model: Add `Remark` class

We have to properly encapsulate the remark in our Person class. Instead of just using a String, let’s follow the conventional class structure that the codebase already uses by adding a Remark class.

Main:

Add Remark to model component (you can copy from Address, remove the regex and change the names accordingly).
Modify RemarkCommand to now take in a Remark instead of a String.

Tests:

Add test for Remark, to test the Remark#equals() method.

[Step 5] Model: Modify `Person` to support a `Remark` field

Now we have the Remark class, we need to actually use it inside Person.

Main:

Add getRemark() in Person.
You may assume that the user will not be able to use the add and edit commands to modify the remarks field (i.e. the person will be created without a remark).
Modify SampleDataUtil to add remarks for the sample data (delete your addressBook.xml so that the application will load the sample data when you launch it.)

[Step 6] Storage: Add `Remark` field to `XmlAdaptedPerson` class

We now have Remark s for Person s, but they will be gone when we exit the application. Let’s modify XmlAdaptedPerson to include a Remark field so that it will be saved.

Main:

Add a new Xml field for Remark.

Tests:

Fix invalidAndValidPersonAddressBook.xml, typicalPersonsAddressBook.xml, validAddressBook.xml etc., such that the XML tests will not fail due to a missing <remark> element.

[Step 6b] Test: Add withRemark() for `PersonBuilder`

Since Person can now have a Remark, we should add a helper method to PersonBuilder, so that users are able to create remarks when building a Person.

Tests:

Add a new method withRemark() for PersonBuilder. This method will create a new Remark for the person that it is currently building.
Try and use the method on any sample Person in TypicalPersons.

[Step 7] Ui: Connect `Remark` field to `PersonCard`

Our remark label in PersonCard is still a placeholder. Let’s bring it to life by binding it with the actual remark field.

Main:

Modify PersonCard's constructor to bind the Remark field to the Person 's remark.

Tests:

Modify GuiTestAssert#assertCardDisplaysPerson(…) so that it will compare the now-functioning remark label.

[Step 8] Logic: Implement `RemarkCommand#execute()` logic

We now have everything set up… but we still can’t modify the remarks. Let’s finish it up by adding in actual logic for our remark command.

Main:

Replace the logic in RemarkCommand#execute() (that currently just throws an Exception), with the actual logic to modify the remarks of a person.

Tests:

Update RemarkCommandTest to test that the execute() logic works.

A.2.3. Full Solution

See this PR for the step-by-step solution.

Appendix B: Product Scope

Target user profile:

JCRC member of a Hall of NUS
has to manage a significant number of hall residents
has to manage budget for CCAs
has to consolidate hall event dates
has to notify hall residents about events
prefers desktop apps over other types
can type fast
prefers typing over mouse input
is reasonably comfortable using CLI apps

Value proposition: manage hall residents faster and easier than a typical mouse/GUI driven app

Appendix C: User Stories

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

Priority As a … I want to … So that I can…

Priority	As a …	I want to …	So that I can…
`* * *`	new JCRC member	see usage instructions	refer to instructions when I forget how to use the App
`* * *`	JCRC member	add a new person
`* * *`	JCRC member	delete a person	remove entries that I no longer need
`* * *`	JCRC member	list all persons
`* * *`	JCRC member	find a person by name	locate details of persons without having to go through the entire list
`* * *`	JCRC member	mass import residents' details	save time from not having to manually key in contacts one by one
`* * *`	JCRC member	delete selected groups of residents	save time from not having to search for and delete persons one by one
`* * *`	JCRC member	delete selected tags from residents	accommodate mass changes in CCA members list
`* * *`	JCRC member	compose emails	ease the process of sending emails to groups of hall residents
`* * *`	JCRC member	delete emails	remove email files that I no longer need
`* * *`	JCRC member	list all emails	see what emails exist
`* * *`	JCRC member	view emails	see the contents of an email
`* * *`	JCRC member	publish calenders	prevent clashes between events and inform hall residents of upcoming events
`* * *`	JCRC Finance Director	keep track of each CCA’s budget	prevent problems during an audit
`* *`	JCRC member	list which residents are in specified CCAs	contact personnel in the CCA more efficiently
`*`	JCRC member	store pictures under contact details	easily identify hall residents and distinguish between those with similar names
`*`	JCRC member	hide private contact details by default	minimize chance of someone else seeing them by accident
`*`	JCRC member	sort persons by name	locate a resident easily

* * *

new JCRC member

see usage instructions

refer to instructions when I forget how to use the App

* * *

JCRC member

add a new person

* * *

JCRC member

delete a person

remove entries that I no longer need

* * *

JCRC member

list all persons

* * *

JCRC member

find a person by name

locate details of persons without having to go through the entire list

* * *

JCRC member

mass import residents' details

save time from not having to manually key in contacts one by one

* * *

JCRC member

delete selected groups of residents

save time from not having to search for and delete persons one by one

* * *

JCRC member

delete selected tags from residents

accommodate mass changes in CCA members list

* * *

JCRC member

compose emails

ease the process of sending emails to groups of hall residents

* * *

JCRC member

delete emails

remove email files that I no longer need

* * *

JCRC member

list all emails

see what emails exist

* * *

JCRC member

view emails

see the contents of an email

* * *

JCRC member

publish calenders

prevent clashes between events and inform hall residents of upcoming events

* * *

JCRC Finance Director

keep track of each CCA’s budget

prevent problems during an audit

* *

JCRC member

list which residents are in specified CCAs

contact personnel in the CCA more efficiently

*

JCRC member

store pictures under contact details

easily identify hall residents and distinguish between those with similar names

*

JCRC member

hide private contact details by default

minimize chance of someone else seeing them by accident

*

JCRC member

sort persons by name

locate a resident easily

Appendix D: Use Cases

(For all use cases below, the System is the Hallper and the Actor is the JCRC member, unless specified otherwise)

Use case: Display usage instructions

MSS

JCRC member requests to view usage instructions
Hallper shows usage instructions

Use case ends.

Use case: Add person

MSS

JCRC member requests to add a person with specific details
Hallper adds the person

Use case ends.

Use case: Delete person

MSS

JCRC member requests to list persons
Hallper shows a list of persons
JCRC member requests to delete a specific person in the list
Hallper deletes the person

Use case ends.

Extensions

2a. The list is empty.

Use case ends.
3a. The given index is invalid.
- 3a1. Hallper shows an error message.
  
  Use case resumes at step 2.

Use case: List persons

MSS

JCRC member requests to list persons
Hallper shows list of all persons

Use case ends.

Use case: Search tag

MSS

JCRC member requests to search by specific tag
Hallper shows list of only persons with specified tag

Use case ends.

Use case: Find person

MSS

JCRC member requests to find person containing specific name
Hallper shows list of persons with matching name

Use case ends.

Use case: Clear persons

MSS

JCRC member requests to clear persons
Hallper clears all persons

Use case ends.

Extensions

1a. JCRC member requests to clear persons with specific tag(s)
- 1a1. Hallper clears all persons with specified tag(s)
  
  Use case ends.

Use case: Import contacts

MSS

JCRC member requests to import contacts from file location
Hallper imports contacts

Use case ends.

Extensions

3a. File is invalid
- 3a1. Hallper shows error message
  
  Use case ends.

Use case: Export contacts

MSS

JCRC member requests to export contacts to location
Hallper exports contacts to location

Use case ends.

Extensions

3a. File is invalid
- 3a1. Hallper shows error message
  
  Use case ends.

Use case: Erase tag

MSS

JCRC member requests to erase specific tag(s)
Hallper erases specified tag(s) from all persons

Use case ends.

Extensions

3a. Tag does not exist
- 3a1. Hallper shows error message
  
  Use case ends.

Use case: Compose email (index)

MSS

JCRC member requests to list persons.
Hallper shows list of persons.
JCRC member requests to compose an email to specific people in the list
Hallper requests for all details of email (Sender, indexes, subject, content)
JCRC member enters all details
Hallper saves an output file in the computer

Use case ends.

Extensions

2a. The list is empty.

Use case ends.
5a. The given index is invalid.
- 5a1. Hallper shows an error message.
  
  Use case resumes at step 4.

Use case: Compose email (list)

MSS

JCRC member requests to list persons
Hallper shows list of persons
JCRC member requests to compose an email to the current list of persons
Hallper requests for all details of email (Sender, subject, content)
JCRC member enters all details
Hallper saves an output file in the computer

Use case ends.

Extensions

2a. The list is empty.

Use case ends.

Use case: List emails

MSS

JCRC member requests to list emails
Hallper shows list of all emails

Use case ends.

Use case: View email

MSS

JCRC member requests to view an email
Hallper requests for email subject
JCRC member enters subject
Hallper displays email with given subject

Use case ends.

Extensions

3a. Email with given subject does not exist.
- 3a1. Hallper shows an error message.
  
  Use case resumes at step 2.

Use case: Select person

MSS

JCRC member requests to list persons
Hallper shows list of persons
JCRC member requests to select a specific person in the list
Hallper shows details of selected person

Use case ends.

Extensions

2a. The list is empty.

Use case ends.
3a. The given index is invalid.
- 3a1. Hallper shows an error message.
  
  Use case resumes at step 2.

Use case: Publish calendar

MSS

JCRC member requests to publish calendar
Hallper requests for the intended calendar month
JCRC member enters the month
Hallper saves an output file in the computer

Use case ends.

Use case: Delete a calendar

MSS

JCRC member requests to delete a calendar
Hallper requests the calendar month
JCRC member enters the month
Hallper deletes the specified calendar

Use case ends.

Extensions

3a. Calendar does not exist
- 3a1. Hallper shows an error message
  
  Use case ends.

Use case: Add event to calendar

MSS

JCRC member requests to add a new event to a calendar
Hallper requests for all details of event (Month, year, day, start time, end time, event name)
JCRC member enters all details
Hallper creates a new event on the calendar

Use case ends.

Extensions

3a. Another event clashes with the same timing
- 3a1. Hallper shows an error message
  
  Use case ends.

Use case: Delete event on a calendar

MSS

JCRC member requests to delete an event on a calendar
Hallper requests for all details of event (Month, year, day, event name)
JCRC member enters all details
Hallper deletes the specified event on the calendar

Use case ends.

Extensions

3a. Event does not exist
- 3a1. Hallper shows an error message
  
  Use case ends.

Use case: Add CCA

MSS

JCRC member requests to add a CCA.
Hallper requests for details of CCA (Name of CCA and allocated budget).
JCRC member enters the details.
Hallper displays the details of the CCA.

Use Case ends.

Extensions

3a. CCA name given is in the wrong format.
- 3a1. Hallper shows an error message
  
  Use case resumes at step 3.
3b. Budget entered is is in the wrong format.
- 3b1. Hallper shows an error message
  
  Use case resumes at step 3.

Use case: Update CCA

MSS

JCRC member requests to modify a specific CCA in the list.
Hallper requests for new details of the CCA (name of CCA, names of head and vice-head, budget, transaction entry number, date, amount transaction remarks).
JCRC member enters the details.
Hallper displays the new details of the CCA.

Use Case ends.

Extensions

3a. The given CCA does not exist in Hallper.
- 3a1. Hallper displays error message
  
  Use case resumes at step 3.
3b. Name(s) of head and/or vice-head is/are not detected in the contact list.
- 3b1. Hallper shows an error message.
  
  Use case resumes at step 3.
3c. Budget entered is invalid.
- 3c1. Hallper shows an error message.
  
  Use case resumes at step 3.
3d. Transaction number not valid for CCA or date. amount, or remarks not in the correct format.
- 3d1. Hallper shows an error message.
  
  Use case resumes at step 3.

Use case: Delete CCA

MSS

JCRC member requests to delete a specific CCA in the list.
Hallper requests for confirmation of deletion.
JCRC member confirms.
Hallper deletes the CCA.

Use Case ends.

Extensions

3a. The given CCA does not exist in Hallper.
- 3a1. Hallper shows an error message.
  
  Use case resumes at step 2.

Use case: List all CCAs

MSS

JCRC member requests for list of CCAs.
Hallper displays list of CCAs.

Use Case ends.

Use case: Add CCA Transaction

MSS

JCRC member requests to add a transaction for a specific CCA in the list.
Hallper requests transaction details (date, amount, remarks).
JCRC member enters transaction details
Hallper displays details of the CCA

Use Case ends.

Extensions

3a. The given CCA is not in Hallper.
- 3a1. Hallper shows an error message.
  
  Use case resumes at step 1.
3b. Date, amount and remarks are not in the correct format.
- 3b1. Hallper shows an error message
  
  Use case resumes at step 1.

Use case: Sort contacts

MSS

JCRC member requests sort the contacts
Hallper sorts the contacts

Use case ends.

Use case: Add image

MSS

JCRC member requests to add a person’s image
Hallper requests for room number and image location
JCRC member enters room number and image location
Hallper adds the image

Use case ends.

Appendix E: Non Functional Requirements

Should work on any mainstream OS as long as it has Java 9 or higher installed.
Should be able to hold up to 1000 persons without a noticeable sluggishness in performance for typical usage.
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.

Appendix F: Glossary

Mainstream OS: Windows, Linux, Unix, OS-X.
Private contact detail: A contact detail that is not meant to be shared with others.
CCA: Co-Curricular Activity that residents can join within their respective halls.
JCRC: Junior Common Room Committee in charge of administrative duties within their respective halls.

Appendix G: Instructions for Manual Testing

Given below are instructions to test the app manually.

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

G.1. Launching and shutting down

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.
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.

G.2. Deleting a person

Deleting a person while all persons are listed.
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) {give more}
  Expected: Similar to previous.

G.3. Composing an email to all currently listed residents

Composing an email while all persons are listed.
1. Prerequisites: List all persons using the list command. Multiple persons in the list.
2. Test case: compose_email_list from/john@gmail.com subject/Example Subject content/Example Content
  Expected: Email displayed on the BrowserPanel with the emails of all listed contacts as recipients of the email.
3. Test case: compose_email_list from/john@gmail.com subject/ content/Example Content
  Expected: Email not displayed on the BrowserPanel. Error details shown in the status message.
4. Test case: compose_email_list from/john subject/Example Subject content/Example Content
  Expected: Email not displayed on the BrowserPanel. Error details shown in the status message.
Composing an email while no persons are listed.
1. Prerequisites: Clear all persons by executing clear all. List should be empty.
2. Test case: compose_email_list from/john@gmail.com subject/Example Subject content/Example Content
  Expected: Email not displayed on the BrowserPanel. Error details shown in the status message.

G.4. Composing an email to specified indexes

Composing an email while all persons are listed.
1. Prerequisites: List all persons using the list command. Multiple persons in the list.
2. Test case: compose_email_index from/john@gmail.com to/1 2 subject/Example Subject content/Example Content
  Expected: Email displayed on the BrowserPanel with the emails of the first and second contact as recipients of the email.
3. Test case: compose_email_index from/john@gmail.com to/100 subject/Example Subject content/Example Content
  Expected: Email not displayed on the BrowserPanel. Error details shown in the status message.
4. Test case: compose_email_index from/john@gmail.com to/0 subject/Example Subject content/Example Content
  Expected: Email not displayed on the BrowserPanel. Error details shown in the status message.
Composing an email while no persons are listed.
1. Prerequisites: Clear all persons by executing clear all. List should be empty.
2. Test case: compose_email_index from/john@gmail.com to/1 2 subject/Example Subject content/Example Content
  Expected: Email not displayed on the BrowserPanel. Error details shown in the status message.

G.5. Deleting an email

Deleting an email that exists
1. Prerequisites: Email to delete exists in the directory in the computer.
2. Test case: delete_email Valid Subject
  Expected: Email with subject 'Valid Subject' is deleted from the computer.
Deleting an email that does not exist
1. Prerequisites: Email to delete does not exist in the directory in the computer.
2. Test case: delete_email Invalid Subject
  Expected: Error details shown in the status message.

G.6. Listing emails

Listing all emails
1. Test case: list_emails
  Expected: Existing emails displayed on the BrowserPanel.

G.7. Viewing an email

Viewing an email that exists
1. Prerequisites: Email to view exists in the directory in the computer.
2. Test case: view_email Valid Subject
  Expected: Email displayed on the BrowserPanel.
Viewing an email that does not exist
1. Prerequisites: Email to view does not exist in the directory in the computer.
2. Test case: view_email Invalid Subject
  Expected: Email not displayed on the BrowserPanel. Error details shown in the status message.

G.8. Creating a monthly calendar

Creating a new monthly calendar.
1. Test case: create_calendar month/oct year/2018
  Expected: "Calendar created: OCT-2018.ics". The GUI remains at the same state as it was before the command execution.
2. Test case: create_calendar month/october year/2018
  Expected: The GUI remains at the same state as it was before the command execution. Error details shown in the status message.
3. Test case: create_calendar month/oct year/-2018
  Expected: The GUI remains at the same state as it was before the command execution. Error details shown in the status message.
Creating an existing monthly calendar.
1. Test case: create_calendar month/oct year/2018
  Expected: The GUI remains at the same state as it was before the command execution. Error details shown in the status message.

It is recommend to test the calendar and its relevant commands using the present month and year as arguments. This is because the calendar GUI will always display the current week as its default time frame.

G.9. Viewing a monthly calendar

Viewing an existing calendar.
1. Test case: view_calendar month/oct year/2018
  Expected: The monthly calendar displays on the UI with the current week as its default time frame.
Viewing a non-existing calendar.
1. Test case: view_calendar month/sep year/1998
  Expected: Error details shown in the status message. The GUI remains at the same state as it was before the command execution.

G.10. Adding an all day event into monthly calendar

Adding a new all day event into the calendar.
1. Test case: add_all_day_event month/oct year/2018 date/25 title/Example
  Expected: The updated calendar displays on the UI with the current week as its default time frame.
2. Test case: add_all_day_event month/oct year/2018 date/-1 title/Example
  Expected: Error details shown in the status message. The GUI remains at the same state as it was before the command execution.
Adding an already existing identical all day event into the calendar.
1. Test case: add_all_day_event month/oct year/2018 date/25 title/Example
  Expected: Displays the monthly calendar on the UI with the current week as its default time frame. Status message shows that the event already exist in the calendar and its duplicate is not created.

Events in Hallper are considered the same if they have the same start date, end date and title (case-sensitive).

G.11. Adding an event into monthly calendar

Adding a new event with a specified time frame into the calendar.
1. Test case: add_event month/oct year/2018 sdate/1 shour/8 smin/0 edate/2 ehour/17 emin/30 title/Example
  Expected: The updated calendar displays on the UI with the current week as its default time frame.
2. Test case: add_event month/oct year/2018 sdate/1 shour/24 smin/0 edate/2 ehour/17 emin/30 title/Example
  Expected: Error details shown in the status message. The GUI remains at the same state as it was before the command execution.
3. Test case: add_event month/oct year/2018 sdate/1 shour/8 smin/0 edate/2 ehour/17 emin/60 title/Example
  Expected: Error details shown in the status message. The GUI remains at the same state as it was before the command execution.
Adding an already existing identical event into the calendar.
1. Test case: add_event month/oct year/2018 sdate/1 shour/8 smin/0 edate/2 ehour/17 emin/30 title/Example
  Expected: Displays the monthly calendar on the UI with the current week as its default time frame. Status message shows that the event already exist in the calendar and its duplicate is not created.

G.12. Deleting an event from monthly calendar

Deleting an existing event from the monthly calendar.
1. Test case: delete_event month/oct year/2018 sdate/25 edate/25 title/example
  Expected: Displays the monthly calendar on the UI with the current week as its default time frame. Status message shows that the event doesn’t exist in the calendar and nothing is deleted. (Event titles are case-sensitive)
2. Test case: delete_event month/oct year/2018 sdate/25 edate/25 title/Example
  Expected: The updated calendar displays on the UI with the current week as its default time frame.

G.13. Clearing persons

Clearing persons while all persons are listed
1. Prerequitsites: List all persons using the list command. Multiple persons in the list.
2. Test case: clear soccer (where soccer exists in list)
  Expected: Person(s) associated with soccer is/are cleared from the list.
3. Test case: clear A123 (where A123 exists in list)
  Expected: Person(s) associated with A123 is/are cleared from the list.
4. Test case: clear soccer A123 (where soccer and/or A123 exist in list)
  Expected: Person(s) associated with soccer or A123 is/are cleared from the list.
5. Test case: clear invalidCCA (where invalidCCA does not exist in list)
  Expected: No person(s) are deleted. No persons cleared message displayed.

G.14. Erasing CCAs

Erasing CCAs while all persons are listed
1. Prerequitsites: List all persons using the list command. Multiple persons in the list.
2. Test case: erase basketball (where basketball exists in list)
  Expected: basketball is removed from associated person(s) in list.
3. Test case: clear basketball soccer (where basketball and soccer exist in list)
  Expected: basketball and soccer are removed from associated person(s) in list.
4. Test case: clear invalidCCA (where invalidCCA does not exist in list)
  Expected: No CCA is erased. No CCAs erased message displayed.

G.15. Exporting data

Exporting Hallper persons to the computer.
1. Prerequisites: C://Users/Me/Documents and ~/Desktop are valid, accessible paths.
2. Test case: export dst/C://Users/Me/Documents fn/export.xml
  Expected: Hallper data exported to export.xml in C://Users/Me/Documents.
3. Test case: export dst/~/Desktop fn/export.xml
  Expected: Hallper data exported to export.xml in ~/Desktop.
4. Test case: export dst/~/Desktop fn/export.txt
  Expected: Data not exported. Invalid file type message displayed.

G.16. Importing data

Importing data files from computer to update Hallper.
1. Prerequisites: Data files created in accessible path on computer with valid format and named import.xml. Refer to User Guide Section 4.1.9 for valid data formats. C://Users/Me/Documents and ~/Desktop are valid, accessible paths.
2. Test case: import dst/C://Users/Me/Documents/import.xml
  Expected: Data imported from import.xml in C://Users/Me/Documents.
3. Test case: import f/~/Desktop/import.xml
  Expected: Data imported from import.xml in ~/Desktop.
4. Test case: import f/C://Users/Me/Documents/import.txt
  Expected: Data not imported. Invalid file type message displayed.

G.17. Searching persons

Searching persons in Hallper.
1. Prerequisites: Multiple persons in Hallper.
2. Test case: search soccer (where a person has soccer tagged). Expected: Persons that are in soccer will be displayed in the Peron List Panel. Number of persons message displayed.
3. Test case: search FoS (where FoS is not tagged to any persons).
  Expected: Person Panel List will be empty. 0 persons message displayed.

G.18. Uploading a profile picture

Uploading of person profile picture from computer to Hallper.
1. Prerequisites: Image files created in accessible path on computer with valid format and named image.jpg. Refer to User Guide Section 4.1.2 for valid data formats. Hallper has at least 1 valid person.
2. Test case: image r/A123 f/C://Users/Me/Documents/image.jpg
  Expected: Image file copied and pasted into Hallper `out/production/resources/profile_picture. The image is named after the person’s room number.
3. Test case: image r/A111 f/C://Users/Me/Documents/image.jpg (where there is no resident tagged to A111).
  Expected: Image not copied. No such person message displayed.
4. Test case: image r/A123 f/NotAFilePath
  Expected: Image not copied. File path error message displayed.
5. Test case: image r/A123 f/FileDontExist.jpg
  Expected: Image not copied. Invalid image error message displayed.

G.19. Creating CCA

Adds a CCA with a given budget
1. Prerequisites: The name of the given CCA only contains alphabets. The budget given is numeric and the only symbol can be used is dash.
2. Test case: create n/Basketball budget/500
  Expected: New CCA added: Basketball Head: - Vice-Head: - Budget: 500
3. Test case: create n/Basketball
  Expected: Invalid command format! create: Create a new CCA to the address book. Parameters: n/CCA NAME budget/BUDGET Example: create n/Basketball budget/500
4. Test case: create
  Expected: Invalid command format! create: Create a new CCA to the address book. Parameters: n/CCA NAME budget/BUDGET Example: create n/Basketball budget/500
5. Test case: create n/Basketball-M budget/500
  Expected: CCA names should only contain alphabet characters and spaces, and it should not be blank!
6. Test case: create n/Basketball budget/$500 Expected: Budget should only contain numbers and it should not be blank.

G.20. Deleting CCA

Deletes a CCA in Hallper.
1. Prerequisites: The specified CCA must exist in Hallper.
2. Test case: delete_cca c/basketball
  Expected: Deleted CCA: Basketball Head: - Vice-Head: - Budget: 500
3. Test case: delete_cca c/tennis
  Expected: The CCA does not exist.
4. Test case: delete_cca
  Expected: Invalid command format! delete_cca: Deletes the CCA specified Parameters: c/CCA Example: delete_cca c/ basketball

G.21. Updating CCA

Update the details of a CCA.
1. Prerequisites: The specified CCA must exist in Hallper. The fields provided must be in the correct format.
2. Test case: update c/hockey h/Peter Park
  Expected: CCA updated: Hockey Head: Peter Park Vice-Head: Bernice Yu Budget: 500
3. Test case: update c/tennis h/Peter Park
  Expected: The CCA does not exist.
4. Test case: update c/hockey trans/1 amount/200
  Expected: CCA updated: Hockey Head: Peter Park Vice-Head: Bernice Yu Budget: 500

G.22. Adding a transaction entry

Adds a transaction entry for a specified CCA in Hallper
1. Prerequisites: The specified CCA must exist in Hallper. The details of the transaction must all be provided and are in the correct format.
2. Test case: add_trans c/hockey date/20.12.2018 amount/-100 remarks/venue booking
  Expected: Transaction added: Hockey Head: Alex Yeoh Vice-Head: Bernice Yu Budget: 500
3. Test case: add_trans c/tennis date/20.12.2018 amount/-100 remarks/venue booking
  Expected: The CCA does not exist. Please create the CCA before. adding its transaction
4. Test case: add_trans c/tennis date/20.12.2018 amount/-100
  Expected: All the fields must be provided. add_trans: Add a new transaction to the specified Cca Parameters: c/CCA date/DD.MM.YYYY amount/AMOUNTremarks/REMARKS Example: add_trans c/basketball date/13.12.2018 amount/-100 remarks/Purchase of equipment

G.23. Deleting a transaction entry

Deletes a transaction entry for a specified CCA in Hallper.
1. Prerequisites: The specified CCA must exist in Hallper. The transaction entry must exist for that CCA.
2. Test case: delete_trans c/basketball trans/1
  Expected: Deleted Cca Transaction Entry: Entry Number: 1 Date: 13.11.2013 Amount: -300 Remarks: Purchase of Equipment
3. Test case: delete_cca c/basketball
  Expected: delete_trans: Deletes the specified transaction entry of the specified CCA Parameters: c/CCA INDEX (must be a positive integer) Example: delete_trans c/ basketball 2
4. Test case: delete_trans c/tennis trans/1
  Expected: The CCA does not exist.

G.24. Showing CCAs' budget

Displays the CCA information and its transaction history.
1. Prerequisites: The specified CCA must exist in Hallper.
2. Test case: budget
  Expected: Display budget.
3. Test case: budget c/basketball
  Expected: Display budget.
4. Test case: budget c/tennis
  Expected: The CCA does not exist.

Hallper - Developer Guide

Events-Driven nature of the design

Logic component

Model component

Ui component

Storage component

Use case: Display usage instructions

Use case: Add person

Use case: Delete person

Use case: List persons

Use case: Search tag

Use case: Find person

Use case: Clear persons

Use case: Import contacts

Use case: Export contacts

Use case: Erase tag

Use case: Compose email (index)

Use case: Compose email (list)

Use case: List emails

Use case: View email

Use case: Select person

Use case: Publish calendar

Use case: Delete a calendar

Use case: Add event to calendar

Use case: Delete event on a calendar

Use case: Add CCA

Use case: Update CCA

Use case: Delete CCA

Use case: List all CCAs

Use case: Add CCA Transaction

Use case: Sort contacts

Use case: Add image

`Logic` component

`Model` component

`Ui` component

`Storage` component