HMS+ - Developer Guide

By: Team T12-1 Since: Feb 2019 Licence: MIT

1. Introduction

HMS+ is a Hotel Management System software that act as a single, highly customizable integrated system to manage all aspects of a hotelier’s requirements. This guide aims to help all developers get familiar with the codebase and teach them how to build upon it.

There are many ways to contribute towards the development of the software: coding, testing, improving the build process and tools or contributing to the documentation. This guide provides information that will not only help you get started as a contributor, but that you’ll find useful to refer to even if you are already an experienced contributor.

2. Setting up

Follow the simple steps below to set up the software and get it running for your system.

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. You can install AsciiDoc for live rendering of documentation.

2.2. Setting up the project in your computer

Fork this repo, 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.
Open MainWindow.java and check for any code errors
1. Due to an ongoing issue with some of the newer versions of IntelliJ, code errors may be detected even if the project can be built and run successfully
2. To resolve this, place your cursor over any of the code section highlighted in red. Press ALT+ENTER, and select Add '--add-modules=…' to module compiler options for each error
Repeat this for the test folder as well (e.g. check HelpWindowTest.java for code errors, and if so, resolve it the same way)

2.3. Verifying the setup

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

2.4. Configurations to do 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. 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)

2.4.3. 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

3.1. Architecture

Figure 1. Architecture Diagram

The Architecture Diagram given above explains the high-level design of the App. It is designed to illustrate and identify the high level architecture systems used to design and implement the HMS+ Application.

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.

Given below is a quick overview of each component.

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

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

Commons represents a collection of classes used by multiple other components. The following class plays an important role at the architecture level:

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: The UI of the App.
Logic: The command executor.
Model: Holds the data of the App in-memory.
Storage: Reads data from, and writes data to, the hard disk.

Each of the four components

Defines its API in an interface with the same name as the Component.
Exposes its functionality using a {Component Name}Manager class.

How the architecture components interact with each other

The Sequence Diagram below shows how the components interact with each other for the scenario where the user issues the command delete-customer 1.

Figure 2. Component interactions for delete-customer 1 command

The sections below give more details of each component.

3.2. UI component

Figure 3. Structure of the UI Component

API : Ui.java The UI consists of a MainWindow that is made up of parts e.g.StatsWindow, HelpWindow, ResultDisplay, CustomerListPanel, StatusBarFooter etc. All these, including the MainWindow, inherit from the abstract UiPart class.

The UI component uses JavaFx UI framework. The layout of these UI parts are defined in matching .fxml files that are in the src/main/resources/view folder. For example, the layout of the MainWindow is specified in MainWindow.fxml

3.2.1. How the UI executes commands

This is handled by function executeCommand defined in MainWindow. The function executeCommand will be passed in CommandBox as a functional interface CommandExecutor which is defined in CommandBox. When adding text in CommandBox and pressed Enter, the command text will be passed to Logic component and be parsed and executed.

3.2.2. How the UI updates itself

This is handled by the InvalidationListenerManager. It is basically a list of InvalidationListeners linked to three lists - UniqueCustomerList, BookingList, ReservationList, RoomTypeList and ServiceTypeList. A listener is added for each of the five lists when the HotelManagementSystem is set up using the addListener() method. Whenever a change is made to any of these five lists of the HotelManagementSystem, all the listeners are called using the indicateModified() method. Thus, the internal listeners when called update the UI automatically.

How the UI automatically filter by selected service type

This is handled by the listener for selected serviceType/roomType inside the booking/reservation list panel. If the selected one is changed, the booking/reservation list panel will run a find command so that the list will be updated accordingly.

How the UI automatically switch tab

The BookingAndReservationPanel and ServiceTypeAndRoomType panel are numbered as 1 and 2. And the tabs inside them are numbered accordingly also. To switch to a certain tab, we need to specify which tab in which panel we want to go. There are two listeners for the two panel. If the selected tab is changed, the panel will switch accordingly. The selected tab can be changed by click and switch command. The selected tab will also be changed accordingly if the command executed is a ReservationCommand or a BookingCommand.

3.3. Logic component

Figure 4. Class Diagram of the Logic Component

API : Logic.java

Logic uses the HotelManagementSystemParser class to parse the user command and invoke the relevant {Command Name}Parser class. This results in a Command object which is executed by the LogicManager using the CustomerModel,BookingModel, etc. based on the type of command. Therefore command execution can affect the CustomerModel,BookingModel, etc. (e.g. adding a customer / editing a booking). Given below is the structure of the command classes.

Figure 5. Structure of the Command classes

The result of the command execution is encapsulated as a CommandResult object which is passed back to the UI. In addition, the CommandResult object can also instruct the User-Interface to perform certain actions, such as displaying help to the user.

3.3.1. Statistics

The statistics features are implemented as a part of the Logic component, since it gathers information from all the models. The Stats object is a singleton that controls all calculations and updating of the individual items of the statistics. The StatsItem objects represent individual items to be displayed, e.g. the most popular room types and service types are two different StatsItem. The ShowStatsCommand emits a message for the MainWindow to open up a new StatsWindow and update its content.

`Stats`

The Stats object takes charge of all aspects of the statistics feature by doing the following:

Maintains a reference to the HMS.
Maintains a list of StatItem to be calculated.
Maintains a list for items that needs to be shown.
Provides a way for the items to be exported to one text report, which would show up in the StatsWindow.
Provides a way to update everything that needs to be shown.

The Stats object is designed in a modular way. If one wants to add a new StatsItem, they simply need to add a new instance of that StatsItem to the items list. Everything else will be taken care of, including calculating and displaying.

`StatsItem`

StatsItem objects are individual items to be computed, or, small fields in the reports. The following information is stored in each StatsItem:

The title of the item is stored in a String.
The results of the stats are stored in a Map<String, Long>.
The way to calculate the stats should be defined in the calcResults function, which would return that Map<String, Long>.
A longest variable which contains the length of the longest string in the keys of the map. This is useful in formatting.

The abstract class also provides a few utility functions for easier creation of new StatItem: - count which turns an observable list (the returned value from all models) to a map of counting, in a way defined by the function provided. - updateLongest which iterates through the list and updates the longest variable. - sortAndFormat whose name suggests what it does.

Usually, the developer only needs to provide the observable list and the function f for count. That f should transform items of the observable list into strings. Then, count will iterate through the observable list, map each element into a string with f, and count how many times the strings have appeared. For example, in the CountRoomTypes item, the observable list is the reservation list, and f maps each reservation into a string of its room type. Many reservations can have the same room type, and then the result will be a Map<String, Long>, the strings of the room types being the key, and the number they appear being the value.

`ShowStatsCommand`

To implement the ShowStatsCommand, which needs to emit messages to the MainWindow, two new arguments for CommandResult are added. One is a boolean value for whether the stats window should show up or not, the other a list for what items to display. Apart from that, the static variable maxIndex is set by the Stats object, for what the maxIndex should be is not known until run time.

3.4. Model component

Figure 6. Structure of the Model Component

Figure 7. Structure of the CustomerModel Component

API : Model.java

The Model,

stores a UserPref object that represents the user’s preferences.
stores the Hotel Management System data.
exposes an unmodifiable ObservableList<Customer/Booking/Reservation/RoomType/ServiceType> that can be 'observed' e.g. the UI can be bound to this list so that the UI automatically updates when the data in the list change.
does not depend on any of the other three components.
The Reservation/Booking/Customer models serve as the API for the application to modify the Reservation/Booking/Customer data.
The Bill model serves the API for the application to generate bills for the customer. It cannot modify data at all. It only has access to ObservableList of the remaining models.

As a more OOP model, we can reference a ServiceType in Booking. This would allow the Hotel Management System to only require one ServiceType instance per unique ServiceType, instead of each Booking needing their own Service object.
Another example is how we store a Tag list in Hotel Management System, which Customer can reference. This would allow Hotel Management System to only require one Tag object per unique Tag, instead of each Customer needing their own Tag object. An example of how such a model may look like is given below.

3.5. Storage component

Figure 8. Structure of the Storage Component

API : Storage.java

The Storage component,

can save UserPref objects in json format and read it back.
can save the Hotel Management System data in json format and read it back.

3.6. Common classes

Classes used by multiple components are in the seedu.hms.commons package.

4. Implementation

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

4.1. How to include a new model

4.1.1. Current Implementation using service booking

In general, when adding any new model and its related commands, you need to work on 3 components compulsorily - Logic, Model and Storage. The UI component is modified based on how you want the user to be able to interact with our newly added model.

You will start by working on the model component. You must create a more specific model which implements the existing Model interface and create a manager for this model. This constitutes the API for our new model how the Logic component will execute the commands related to the model. For Booking, there is a BookingModel interface and a BookingManager class which keeps track of a booking list. An 'observable booking list' is bounded to the UI using listeners so that the UI can be updated as the list changes. While the interface is a means of exposing the API, the manager class links with the system and performs the actions. We also create the relevant class files to represent the model we are implementing. For example, for representing our list of reservations, we create relevant classes like ReservationList, Reservation, DateRange, RoomType, etc.\

Figure 9. Changes in the Model Structure

Then you need to add the command files and parser files so that the application can parse commands related to the model and execute them. The commands have been separated for different models by adding an interface in the middle. This interface makes sure the correct model is used to execute those commands. For example, there is a CustomerCommand and a BookingCommand interface which implements the Command interface. Moreover the CustomerCommand interface specifies that it uses the CustomerModel to execute itself. Then each command (eg. AddBookingCommand, EditBookingCommand, etc.) implements the BookingCommand interface. This makes sure that only the booking manager can be used to execute these commands as well. You also need to add parser classes for each command you implement (eg. AddBookingCommandParser). These classes are invoked in the HotelManagementSystemParser to get back the CommandResult which is used by the UI.

Figure 10. The new command structure

If the new model needs to be stored, then you also need to define JSON adapted classes to represent these models. The JsonSerializableHotelManagementSystem has a list of JsonAdaptedCustomer and a list of JsonAdaptedBooking and these two lists are saved using seedu.hms.commons.util.JsonUtil. For each model class, you need to define a JSON-adapted class with a toModelType function so that the system can read the data back from the file.

The modifications in the UI for a new model depend heavily on the functionality it provides. For booking and reservations, a panel was added to display all the bookings/reservations which can be filtered based on different parameters. You can see the addition, updating and deletion of bookings in real-time in the UI as has been explained before.

4.1.2. Design Considerations

Aspect: How should the API be structured

Alternative 1 (current choice): Every model has a separate interface which implements the Model interface
- Pros: Every model has access to the GUI and User Preferences.
- Cons: Some models have unnecessary methods.
Alternative 2: All the model APIs will be separate and there will be no Model Interface.
- Pros: Better separation and less scope for errors.
- Cons: Lot of refactoring required.

4.2. Making a model customizable

4.2.1. Current Implementation

In this section a model is considered to be customizable if an instance of it can be:

Added
Edited
Deleted
Listed (or Displayed)

You can relate this with the infamous CRUD cycle if you are familiar with it.

Every model/manager has access to the HotelManagementSystem inside which resides all the lists (BookingList, UniqueCustomerList, etc.). These lists have methods to add an item, set or replace an item at a particular index and delete an item. Therefore, when you are implementing a model and its list wrapper (Eg. ReservationList), you must include these functions. You must also define equality between instances of a model created so that it is easy to find an instance and replace it. Include an instance of your list inside the HotelManagementSystem and add a listener to it to automatically update the UI every time the function indicateModified is called. Based on the action, you might want to update the shown list using the updateFiltered#{Model Name}List method. A sequence diagram is given below to make the following more clear.

Figure 11. Sequence diagram for add-customer

4.2.2. Design Considerations

Aspect: Editing a model object

Alternative 1: Allowing objects to be edited
- Pros: We avoid recreating new instances and will have better performance.
- Cons: It is very hard to update the UI every time an object is added or updated.
Alternative 2 (current choice): Replacing objects with a new object with edited parameters
- Pros: Lot of instances are created and we need to make sure the old object doesn’t reappear again.
- Cons: It is easy to update the UI using a listener for each list.

4.3. Filtering service booking functionality

4.3.1. Current Implementation

To find and filter the service bookings, we need to work on Logic, Model and Storage components. We can start on the Logic component. According to the current implementation, a command can only take in one model — either a customer model or a booking model. Limited by this, we cannot get access to customer list and booking list at the same time in one command. To implement the function without changing the base abstraction, we used identification number to check whether the payer of the booking is the customer we are selecting instead of using the index of a customer. The reason we use identification number(ID) instead of name or other factors is that the ID of one customer is unique.

The FindBookingCommand involves the use of multiple components of the HMS+ application. The figure below shows the high level Sequence Diagram for the FindBookingCommand.

Figure 12. High Level Sequence Diagram for the find-booking id/A0176684J command

4.3.2. Design Considerations

Aspect: How should the customer be stressed

Alternative 1 (current choice): Using identification number(ID) to check.
- Pros: The command can be implemented as only getting access to one model.
- Cons: The scalability of the program is low.
Alternative 2: Implementing new command interface which can interact with two models at the same time.
- Pros: The scalability of the program is high
- Cons: Requiring more work and the old abstraction may break.

4.4. Filtering Room Reservation functionality

4.4.1. Current Implementation

The finding a specific room reservation functionality is facilitated by the FindReservationCommand class and is used whenever the hotel staff wants to find a specific reservation done by the customer. It reduces the tedious process that the hotel staff needs to do and helps them find the reservation in one go. To facilitate this, it depends on the ReservationModel interface which provides the API for the room reservation and room type component.

The FindReservationCommand extends from the ReservationCommand class which in turn extends from the Command class. This is illustrated in the UML diagram shown below.

Figure 13. FindReservationCommand UML Diagram

The FindReservationCommand involves the use of multiple components of the HMS+ application. The figure below shows the high level Sequence Diagram for the FindReservationCommand.

Figure 14. High Level Sequence Diagram for the find-reservation id/A0176684J command

As seen from the above diagram, this command doesn’t affect storage at all as the purpose of this command is to just find a specific reservation.

The Logic is responsible for parsing FindReservationCommand. It return a FindReservationCommand object after parsing the filters provided by the hotel staff.

The FindReservationCommand#execute() method invokes the updateFilteredList(reservationPredicate) method from the ReservationModel.

The ReservationModel component filters the reservation list based on the filters given by the user and sends this filtered list back to the Logic which in turn sends it back to the Ui for displaying the specific room reservation.

4.4.2. Design Consideration

Aspect: How to find the customer whose specific reservation is to be found

Alternative 1 (current choice): We use the customer’s identification number to find the particular customer
- Pros: Identification number of a customer is unique making it easy to find the customer.
- Cons: The extensibility of the program is low as it only uses identification number.
Alternative 2: We allow any customer field to be used as a filter.
- Pros: The extensibility of the program is high as any customer field can be used a filter.
- Cons: Filters for all customer fields need to be created and some customer fields like name or date of birth are not unique to customers.

Aspect: How to implement the command

Alternative 1 (current choice): The command only has access to ReservationModel interface and can therefore only be used to filter reservations.
- Pros: Follows the Single Responsibility Principle and maintains abstraction.
- Cons: Each command only has access to one model, which causes scalability to low.
Alternative 2: Create an interface which allows commands to have access to two or more models together.
- Pros: The scalability is high as each command can access various models.
- Cons:: This might break abstraction and does not follow the Single Responsibility Principle.

4.5. Generating Bill for Customers

4.5.1. Current Implementation

The generate bill for customer functionality is facilitated by the GenerateBillForCustomerCommand class and is used whenever the hotel staff wants to generate bills for its customers. It allows the hotel staff to generate bills for their customers in one go. To facilitate this, it depends on the BillModel interface and the CustomerModel interface which provide the API for the bill component.

The GenerateBillForCustomerCommand extends from the BillCommand class which in turn extends from the Command class. This is illustrated in the UML diagram shown below.

Figure 15. GenerateBillForCustomerCommand UML Diagram

The GenerateBillForCustomerCommand involves the use of multiple components of the HMS+ application. The figure below shows the high level Sequence Diagram for the GenerateBillForCustomerCommand.

Figure 16. High Level Sequence Diagram for the generate-bill-customer 1 command

As seen from the above diagram, there is no storage created for the bill as a result of which the bill generated is never stored. Therefore, the bill needs to be generated every time.

The GenerateBillForCustomerCommandParser is responsible for parsing the command. It return an GenerateBillForCustomerCommand object after parsing the index of the customer whose bill is to be generated. The figure below depicts the Sequence Diagram for interactions within the Logic component for the execute(generate-bill-customer 1) API call.

Figure 17. Interactions inside the Logic Component for the generate-bill-customer 1 command

The GenerateBillForCustomerCommand#execute() method invokes the updateBill(bill) method from the BillModel. Complying with the rules of [abstraction], the Logic component calls on Model to handle the internal details for updating.

The code used for generating the booking bill for the customer is shown in the snippet below:

public HashMap<ServiceType, Pair<Double, Integer>> generateHashMapForBooking(ObservableList<Booking>
                                                                                bookingObservableList) {

        HashMap<ServiceType, Pair<Double, Integer>> bookingBill = new HashMap<>();
        for (ServiceType st: serviceTypeList) {
            bookingBill.put(st, generateTotalBillBasedOnServiceType(bookingObservableList, st));
        }
        return bookingBill;
    }

 private Pair<Double, Integer> generateTotalBillBasedOnServiceType(ObservableList<Booking> bookingObservableList,
                                                                      ServiceType serviceType) {
        int totalTime = 0;
        double totalAmount = 0.0;
        for (Booking booking : bookingObservableList) {
            if ((booking.getService().equals(serviceType))) {
                TimeRange timeRange = booking.getTiming();
                int hoursBooked = timeRange.numOfHours();
                totalTime = totalTime + hoursBooked;
                double ratePerHour = booking.getService().getRatePerHour();
                double amount = hoursBooked * ratePerHour;
                totalAmount = totalAmount + amount;
            }
        }
        return new Pair<>(totalAmount, totalTime);
    }

The reservation bill for the customer is also generated in the same manner and has therefore not been shown. The two bills are then combined and showed to the user.

4.5.2. Design Consideration

Aspect: How should bill generation be implemented

Alternative 1 (current choice): An entirely new model, BillModel has been implemented which helps in generating a bill.
- Pros: The BillModel interface can be extended to perform other functions related to bill generation if required. If new features get added, the BillModel will help in extending them without hassle or changing already implemented functions.
- Cons: Initially, a lot of work needs to go in implementing the model.
Alternative 2: Adding functions to the HotelManagementSystem class which will generate the bill.
- Pros: Easy to implement. Takes less time and less work required.
- Cons: Every-time a new feature is to be added, changes in the already implemented functions will also have to be done accordingly, creating more work.

4.5.3. Aspect: Memory storage for bill

Alternate 1 (current choice): Bill doesn’t get stored.
- Pros: No work required to be done for storing the bills. Storage space is also saved.
- Cons: While implementing new features that require history of bills, the system will not be able to provide it.
Alternative 2: Bill gets stored.
- Pros: If bill history is required for a new feature, system will be able to provide it.
- Cons: Storing of bills will create duplicates of most of the data, as bill uses only existing data to generate output to customer and doesn’t add any new data. As a result of this, if bill gets stored it will just create duplication of data and cost the user more space.

4.6. Clear functionality

4.6.1. Current Implementation

The clearing mechanism of HMS+ is facilitated by 5 different commands - ClearRoomTypeCommand, ClearServiceTypeCommand, ClearReservationCommand,ClearBookingCommand and ClearHotelManagementSystemCommand - and each of these commands clear specific parts of the database.

Let’s first understand which commands clears which part of the database.

ClearBookingCommand clears all the bookings from the database.
ClearServiceTypeCommand clear all service types from the database.
ClearReservationCommand clears all the reservations from the database.
ClearRoomTypeCommand clear all room types from the database.
ClearHotelManagementSystemCommand clears the entire database.

All the 5 commands have been implemented in the exact way. Therefore we will just go through the underlying structure of the ClearHotelManagementSystemCommand.

Currently, the ClearHotelManagementSystemCommand extends from the Command class. The figure below shows the UML Diagram for the ClearHotelManagementSystemCommand class.

4.7. Undo/Redo feature

4.7.1. Current Implementation

The undo/redo mechanism is facilitated by VersionedHotelManagementSystem. It extends HotelManagementSystem with an undo/redo history, stored internally as an hotelManagementSystemStateList and currentStatePointer. Additionally, it implements the following operations:

VersionedHotelManagementSystem#commit() — Saves the current hotel management system state in its history.
VersionedHotelManagementSystem#undo() — Restores the previous hotel management system state from its history.
VersionedHotelManagementSystem#redo() — Restores a previously undone hotel management system state from its history.

These operations are exposed in the Model interface as Model#commitHotelManagementSystem(), Model#undoHotelManagementSystem() and Model#redoHotelManagementSystem() 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 VersionedHotelManagementSystem will be initialized with the initial hotel management system state, and the currentStatePointer pointing to that single hotel management system state.

Step 2. The user executes delete 5 command to delete the 5th customer in the hotel management system. The delete command calls Model#commitHotelManagementSystem(), causing the modified state of the hotel management system after the delete 5 command executes to be saved in the hotelManagementSystemStateList, and the currentStatePointer is shifted to the newly inserted hotel management system state.

Step 3. The user executes add n/David … to add a new customer. The add command also calls Model#commitHotelManagementSystem(), causing another modified hotel management system state to be saved into the hotelManagementSystemStateList.

If a command fails its execution, it will not call Model#commitHotelManagementSystem(), so the hotel management system state will not be saved into the hotelManagementSystemStateList.

Step 4. The user now decides that adding the customer was a mistake, and decides to undo that action by executing the undo command. The undo command will call Model#undoHotelManagementSystem(), which will shift the currentStatePointer once to the left, pointing it to the previous hotel management system state, and restores the hotel management system to that state.

If the currentStatePointer is at index 0, pointing to the initial hotel management system state, then there are no previous hotel management system states to restore. The undo command uses Model#canUndoHotelManagementSystem() 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#redoHotelManagementSystem(), which shifts the currentStatePointer once to the right, pointing to the previously undone state, and restores the hotel management system to that state.

If the currentStatePointer is at index hotelManagementSystemStateList.size() - 1, pointing to the latest hotel management system state, then there are no undone hotel management system states to restore. The redo command uses Model#canRedoHotelManagementSystem() 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 hotel management system, such as list, will usually not call Model#commitHotelManagementSystem(), Model#undoHotelManagementSystem() or Model#redoHotelManagementSystem(). Thus, the hotelManagementSystemStateList remains unchanged.

Step 6. The user executes clear, which calls Model#commitHotelManagementSystem(). Since the currentStatePointer is not pointing at the end of the hotelManagementSystemStateList, all hotel management system 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:

4.7.2. Design Considerations

Aspect: How undo & redo executes

Alternative 1 (current choice): Saves the entire hotel management system.
- 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 customer being deleted).
- Cons: We 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 hotel management system 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 VersionedHotelManagementSystem.
Alternative 2: Use HistoryManager for undo/redo
- Pros: We 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.

4.8. Logging

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

The logging level can be controlled using the logLevel setting in the configuration file (See Section 4.9, “Configuration”)
The Logger for a class can be obtained using LogsCenter.getLogger(Class) which will log messages according to the specified logging level
Currently log messages are output through: Console and to a .log file.

Logging Levels

SEVERE : Critical problem detected which may possibly cause the termination of the application
WARNING : Can continue, but with caution
INFO : Information showing the noteworthy actions by the App
FINE : Details that is not usually noteworthy but may be useful in debugging e.g. print the actual list instead of just its size

4.9. Configuration

Certain properties of the application can be controlled (e.g user prefs file location, 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 web pages.

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 18. 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 1. List of site-wide attributes
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

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 2. List of per-file attributes, excluding Asciidoctor’s built-in attributes
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

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 your application is an integral part of the app development process. Testing allows you to verify the correctness, functional behaviour, and usability of your app before you release it publicly.

Consider this. You have just implemented a new feature and want to test it. Or you want to add tests for an existing feature because you have decided that there are not enough tests. But the problem arises, when you have to think about where to start. What code or features do the current tests test? Do these overlap? Therefore, in short, you have to decide where to implement your new tests and what to cover in them.

This document is a starting point for you, the contributors and the developers, to understand about the automated tests implemented and how to run them.

Below you will find a short summary on the kind of tests already implemented and how to run them.

6.1. Running Tests

There are three ways you can run tests in.

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'. Currently it covers Customer and Booking related functions.
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.hms.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.hms.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.hms.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.hms.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

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, Hotel Management System depends on the Jackson library for JSON parsing. Managing these dependencies can be automated using Gradle. For example, Gradle can download the dependencies automatically, which is better than these alternatives:

Include those libraries in the repo (this bloats the repo size)
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 customers 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).
  
  HotelManagementSystemParser is responsible for analyzing command words.
- Solution
  
  Modify the switch statement in HotelManagementSystemParser#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 hotel management system, 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 hotel management system.
- Hints
  
  The Model and the HotelManagementSystem 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 HotelManagementSystem and Customer classes can be used to implement the tag removal logic. HotelManagementSystem allows you to update a customer, and Customer allows you to update the tags.
- Solution
  
  Implement a removeTag(Tag) method in HotelManagementSystem. Loop through each customer, and remove the tag from each customer.
  
  Add a new API method deleteTag(Tag) in ModelManager. Your ModelManager should call HotelManagementSystem#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 hotel management system 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 customer 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 customer 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 CustomerCard 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 CustomerCard '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 HotelManagementSystemSystemTest#assertCommandBoxShowsDefaultStyle() and HotelManagementSystemSystemTest#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 hotel management system.

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 hotel management system is updated.
- Solution
  
  Modify the constructor of StatusBarFooter to take in the number of customers when the application just started.
  
  Use StatusBarFooter#handleHotelManagementSystemChangedEvent(HotelManagementSystemChangedEvent) to update the number of customers whenever there are new changes to the hotel management system.
  
  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 HotelManagementSystemSystemTest to also verify the new total number of customers 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 hotel management system to the cloud. However, the current implementation of the application constantly saves the hotel management system 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 hotel management system storage.

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

Add a new method backupHotelManagementSystem(ReadOnlyHotelManagementSystem), so that the hotel management system can be saved in a fixed temporary location.
- Hint
  
  Add the API method in HotelManagementSystemStorage interface.
  
  Implement the logic in StorageManager and JsonHotelManagementSystemStorage 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 HMS+, 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 customer specified in the INDEX.
Format: remark INDEX r/[REMARK]

Examples:

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

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 HotelManagementSystemParser to accept a RemarkCommand.

Tests:

Add RemarkCommandTest that tests that execute() throws an Exception.
Add new test method to HotelManagementSystemParserTest, 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 HotelManagementSystemParser 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 HotelManagementSystemParserTest to test that the correct command is generated according to the user input.

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

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

Main:

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

Tests:

Modify CustomerCardHandle 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 Customer 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 `Customer` to support a `Remark` field

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

Main:

Add getRemark() in Customer.
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 customer will be created without a remark).
Modify SampleDataUtil to add remarks for the sample data (delete your data/hotelManagementSystem.json so that the application will load the sample data when you launch it.)

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

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

Main:

Add a new JSON field for Remark.

Tests:

Fix invalidAndValidCustomerHotelManagementSystem.json, typicalCustomersHotelManagementSystem.json, validHotelManagementSystem.json etc., such that the JSON tests will not fail due to a missing remark field.

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

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

Tests:

Add a new method withRemark() for CustomerBuilder. This method will create a new Remark for the customer that it is currently building.
Try and use the method on any sample Customer in TypicalCustomers.

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

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

Main:

Modify CustomerCard's constructor to bind the Remark field to the Customer 's remark.

Tests:

Modify GuiTestAssert#assertCardDisplaysCustomer(…) 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 customer.

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

HMS+ is targeted at hotels which want to use a single, highly customizable integrated system to manage all the aspects their requirements.

Hotels have hundreds of customers with each customer having their own service bookings, room reservations and their payments.

This is why these hotels use different software to keep a track of customer’s bookings and reservations and accordingly their payments. With time, it becomes difficult to keep a track of everything using different software.

HMS+ provides hotels with a one-stop shop for all their managerial and organization needs.

Target user profile:

Hoteliers
Hotel Management Staff

Value proposition: hotels can efficiently manage its entire database faster than a typical mouse/GUI driven app.

Appendix C: User Stories

User stories are short, simple descriptions of a feature told from the perspective of the user who desires the new capability. This will help the existing and new developers understand the importance of each feature and how does it help our user.

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 hotel management staff	see usage instructions	refer to instructions when I forget how to use the App
`* * *`	hotel management staff	add a new customer	add a room reservation or a service booking for the customer
`* * *`	hotel management staff	delete a customer	remove a customer
`* * *`	hotel management staff	edit a customer	update details of an already existing customer
`* * *`	hotel management staff	find a customer by name	locate details of customers without having to go through the entire list
`* * *`	hotel management staff	add a new room reservation	allocate a room to a customer
`* * *`	hotel management staff	delete a room reservation	remove a room reservation
`* * *`	hotel management staff	edit a room reservation	update details of an already existing room reservation
`* * *`	hotel management staff	add a new service booking	allocate a service to a customer
`* * *`	hotel management staff	delete a service booking	remove a service booking
`* * *`	hotel management staff	edit a service booking	update details of an already existing service booking
`* * *`	hotel management staff	generate bill	show the customer the remaining he has to pay for his stay at the hotel
`* *`	hotel management staff	sort reservations by date	see closer reservations first
`* *`	hotel management staff	sort customers by amount due	see which customer owes more first
`* *`	hotel management staff	view all room reservations	know which rooms are occupied and when
`* *`	hotel management staff	view all service bookings	know which rooms are occupied and when
`* *`	hotel management staff	view all customers	know who all are customers in my hotel
`* *`	hotel management staff	view services provided by hotel	select which service to book for customer
`* *`	hotel management staff	view room types provided by hotel	select which room type to reserve for customer
`*`	hotel management staff	send people for cleaning a room	get a room cleaned and ready for next customer
`*`	hotel management staff	upgrade a customer to VIP status	give him VIP discounts
`*`	hotel management staff	add a new service	expand my service range
`*`	hotel management staff	change rates of a service	change their tariffs
`*`	hotel management staff	add a new room type	expand my room type range
`*`	hotel management staff	change rates of a room type	change their tariffs
`*`	hotel management staff	change capacity of a specific service	expand/shrink a specific service
`*`	hotel management staff	sort customers by name	locate a customer easily

* * *

new hotel management staff

see usage instructions

refer to instructions when I forget how to use the App

* * *

hotel management staff

add a new customer

add a room reservation or a service booking for the customer

* * *

hotel management staff

delete a customer

remove a customer

* * *

hotel management staff

edit a customer

update details of an already existing customer

* * *

hotel management staff

find a customer by name

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

* * *

hotel management staff

add a new room reservation

allocate a room to a customer

* * *

hotel management staff

delete a room reservation

remove a room reservation

* * *

hotel management staff

edit a room reservation

update details of an already existing room reservation

* * *

hotel management staff

add a new service booking

allocate a service to a customer

* * *

hotel management staff

delete a service booking

remove a service booking

* * *

hotel management staff

edit a service booking

update details of an already existing service booking

* * *

hotel management staff

generate bill

show the customer the remaining he has to pay for his stay at the hotel

* *

hotel management staff

sort reservations by date

see closer reservations first

* *

hotel management staff

sort customers by amount due

see which customer owes more first

* *

hotel management staff

view all room reservations

know which rooms are occupied and when

* *

hotel management staff

view all service bookings

know which rooms are occupied and when

* *

hotel management staff

view all customers

know who all are customers in my hotel

* *

hotel management staff

view services provided by hotel

select which service to book for customer

* *

hotel management staff

view room types provided by hotel

select which room type to reserve for customer

*

hotel management staff

send people for cleaning a room

get a room cleaned and ready for next customer

*

hotel management staff

upgrade a customer to VIP status

give him VIP discounts

*

hotel management staff

add a new service

expand my service range

*

hotel management staff

change rates of a service

change their tariffs

*

hotel management staff

add a new room type

expand my room type range

*

hotel management staff

change rates of a room type

change their tariffs

*

hotel management staff

change capacity of a specific service

expand/shrink a specific service

*

hotel management staff

sort customers by name

locate a customer easily

Appendix D: Use Cases

(For all use cases below, the System is the HMS+ and the Actor is the Hotel Staff, unless specified otherwise)

Use case: Add reservation

Main Success Scenario

The actor adds a reservation.
The system adds the reservation to its list of reservations.

Use case resumes at step 1.

Extensions

1a. The actor tries to add invalid reservation.
- 1a1. The system shows an error.
  
  Steps 1 - 1a1 are repeated till a valid reservation is provided.
  
  Use case ends.

Use case: Edit reservation

Main Success Scenario

The actor requests all the reservations in the system.
The system lists the reservations requested.
The actor requests to edit a reservation at a specified index.
The system edits the reservation.

Use case resumes at step 3.

Extensions

2a. The system has no reservations.

Use case ends.
3a. The index that the actor specified is invalid.
- 3a1. The system shows an error message.
  
  Steps 3 - 3a1 are repeated till a valid index is provided.

Use case: List reservations

Main Success Scenario

The actor requests to see all the reservations in the system.
The system lists the reservations requested.

Use case: Delete reservation

Main Success Scenario

The actor requests all the reservations in the system.
The system lists the reservations requested.
The actor requests to delete a reservation at a specified index.
The system deletes the reservation.

Use case resumes at step 3.

Extensions

2a. The system has no reservations.

Use case ends.
3a. The index that the actor specified is invalid.
- 3a1. The system shows an error message.
  
  Steps 3 - 3a1 are repeated till a valid index is provided.

Use case: Add booking

Main Success Scenario

The actor adds a booking.
The system adds the booking to its list of bookings.

Use case resumes at step 1.

Extensions

1a. The actor tries to add invalid booking.
- 1a1. The system shows an error.
  
  Steps 1 - 1a1 are repeated till a valid booking is provided.
  
  Use case ends.

Use case: Edit booking

Main Success Scenario

The actor requests all the bookings in the system.
The system lists the bookings requested.
The actor requests to edit a booking at a specified index.
The system edits the booking.

Use case resumes at step 3.

Extensions

2a. The system has no bookings.

Use case ends.
3a. The index that the actor specified is invalid.
- 3a1. The system shows an error message.
  
  Steps 3 - 3a1 are repeated till a valid index is provided.

Use case: List bookings

Main Success Scenario

The actor requests to see all the bookings in the system.
The system lists the bookings requested.

Use case: Delete booking

Main Success Scenario

The actor requests all the bookings in the system.
The system lists the bookings requested.
The actor requests to delete a booking at a specified index.
The system deletes the booking.

Use case resumes at step 3.

Extensions

2a. The system has no bookings.

Use case ends.
3a. The index that the actor specified is invalid.
- 3a1. The system shows an error message.
  
  Steps 3 - 3a1 are repeated till a valid index is provided.

Use case: Add room-type

Main Success Scenario

The actor adds a room-type.
The system adds the room-type to its list of room-types.

Use case resumes at step 1.

Extensions

1a. The actor tries to add invalid room-type.
- 1a1. The system shows an error.
  
  Steps 1 - 1a1 are repeated till a valid room-type is provided.
  
  Use case ends.

2a. The actor tries to add an already existing room type.
- 2a1. The system shows an error.
  
  Steps 2 - 2a1 are repeated till a new room-type is provided.
  
  Use case ends.

Use case: Edit room-type

Main Success Scenario

The actor requests all the room-types in the system.
The system lists the room-types requested.
The actor requests to edit a room-type at a specified index.
The system edits the room-type.

Use case resumes at step 3.

Extensions

2a. The system has no room-types.

Use case ends.
3a. The index that the actor specified is invalid.
- 3a1. The system shows an error message.
  
  Steps 3 - 3a1 are repeated till a valid index is provided.

3b. The actor tries to edit the room type to an already existing room type.
- 3b1. The system shows an error.
  
  Steps 3 - 3b1 are repeated till a new room-type is provided.
  
  Use case ends.

Use case: Delete room-type

Main Success Scenario

The actor requests all the room-types in the system.
The system lists the room-types requested.
The actor requests to delete a room-type at a specified index.
The system deletes the room-type.

Use case resumes at step 3.

Extensions

2a. The system has no room-types.

Use case ends.
3a. The index that the actor specified is invalid.
- 3a1. The system shows an error message.
  
  Steps 3 - 3a1 are repeated till a valid index is provided.

Use case: Add service

Main Success Scenario

The actor adds a service.
The system adds the service to its list of services.

Use case resumes at step 1.

Extensions

1a. The actor tries to add invalid service.
- 1a1. The system shows an error.
  
  Steps 1 - 1a1 are repeated till a valid service is provided.
  
  Use case ends.

2a. The actor tries to add an already existing room type.
- 2a1. The system shows an error.
  
  Steps 2 - 2a1 are repeated till a new service is provided.
  
  Use case ends.

Use case: Edit service

Main Success Scenario

The actor requests all the services in the system.
The system lists the services requested.
The actor requests to edit a service at a specified index.
The system edits the service.

Use case resumes at step 3.

Extensions

2a. The system has no services.

Use case ends.
3a. The index that the actor specified is invalid.
- 3a1. The system shows an error message.
  
  Steps 3 - 3a1 are repeated till a valid index is provided.

3b. The actor tries to edit the room type to an already existing room type.
- 3b1. The system shows an error.
  
  Steps 3 - 3b1 are repeated till a new service is provided.
  
  Use case ends.

Use case: Delete service

Main Success Scenario

The actor requests all the services in the system.
The system lists the services requested.
The actor requests to delete a service at a specified index.
The system deletes the service.

Use case resumes at step 3.

Extensions

2a. The system has no services.

Use case ends.
3a. The index that the actor specified is invalid.
- 3a1. The system shows an error message.
  
  Steps 3 - 3a1 are repeated till a valid index is provided.

D.1. Use case: Generate total bill for a specific customer

Main Success Scenario

The actor requests the list of all the customers.
The system lists all the customers.
The actor requests to generate total bill for a specific customer.
The system generates the total bill for that specific customer.

Extensions

2a. There are no customers

Use case ends.
3a. The command that the actor entered is invalid.
- 3a1. The system shows an error message that the command is invalid.
  
  Use case resumes at step 3.
3b. The index that the actor selected is invalid.
- 3b1. The system shows an error message that the index is invalid.
  
  Use case resumes at step 3.

3b. The index that the actor selected is wrong.
- 3b1. The system generates the bill for a different customer, not the intended one.
  
  Use case resumes at step 3.

Use case: Generate booking bill for a specific customer

Main Success Scenario

The actor requests the list of all customers.
The system lists all the customers.
The actor requests to generate total bill for a specific customer.
The system generates the total bill for that specific customer.

Use case resumes at step 3

Extensions

2a. There are no customers

Use case ends.
3a. The command that the actor entered is invalid.
- 3a1. The system shows an error message that the command is invalid.
  
  Use case resumes at step 3.
3b. The index that the actor selected is invalid.
- 3b1. The system shows an error message that the index is invalid.
  
  Use case resumes at step 3.

3b. The index that the actor selected is wrong.
- 3b1. The system generates the booking bill for a different customer, not the intended one.
  
  Use case resumes at step 3.

Use case: Finding the specific list of bookings

Main Success Scenario

The actor requests for the specific list of bookings.
The system shows the specific list of bookings.

Use case resumes at step 1.

Extensions

1a. The command that the actor entered is invalid.
- 1a1. The system shows an error message that the command is invalid.
  
  Use case resumes at step 1.

1b. The identification number that the actor entered is in wrong format.
- 1b1. The system shows an error message that the identification number has been not entered in the correct format.
  
  Use case resumes at step 1.

1c. The identification number that the actor entered is wrong.
- 1c1. The system shows the specific list of bookings with the wrong identification number.
  
  Use case resumes at step 1.

Use cases for ServiceType and TimeRange can be created in a similar manner like steps 1b and 1c.

Use case: Finding the specific list of reservations

Main Success Scenario

The actor requests for the specific list of reservations.
The system shows the specific list of reservations.

Use case resumes at step 1.

Extensions

1a. The command that the actor entered is invalid.
- 1a1. The system shows an error message that the command is invalid.
  
  Use case resumes at step 1.

1b. The identification number that the actor entered is in wrong format.
- 1b1. The system shows an error message that the identification number has been not entered in the correct format.
  
  Use case resumes at step 1.

1c. The identification number that the actor entered is wrong.
- 1c1. The system shows the specific list of reservations with the wrong identification number.
  
  Use case resumes at step 1.

Use cases for RoomType and DateRange can be created in a similar manner like steps 1b and 1c.

Use case: Clear all reservations

Main Success Scenario

The actor requests the list of all reservations.
The system shows the list of all reservations.
The actor requests to clear all reservations.
The system clears all the reservations.

Extensions

2a. The list of reservations is empty.

Use case ends.

3a. The command that the actor entered is invalid.
- 3a1. The system shows an error message that the command is invalid.
  
  Use case resumes at step 3.

Use case: Clear all bookings

Main Success Scenario

The actor requests the list of all bookings.
The system shows the list of all bookings.
The actor requests to clear all bookings.
The system clears all the bookings.

Extensions

2a. The list of bookings is empty.

Use case ends.

3a. The command that the actor entered is invalid.
- 3a1. The system shows an error message that the command is invalid.
  
  Use case resumes at step 3.

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 customers 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

Abstraction: In Object-oriented Programming, abstraction is the mechanism by which users are provided with only the functionality, and not the implementation details. So, abstraction provides users with information on what an object does, rather than how it does it.
Single Responsibility Principle: The single responsibility principle is a computer programming principle that states that every module, class, or function should have responsibility over a single part of the functionality provided by the software, and that responsibility should be entirely encapsulated by the class.
CLI: Acronym for Command Line Interface. It is a purely text-based interface for software. User respond to visual prompts by typing single commands into the interface and receive results as text as well. For example: MS-DOS.
GUI: Acronym for Graphical User Interface. In a GUI, the software interface consists of graphical icons, menus and/or other visual indicators to display information. Users can typically interact with these graphics, rather than just using text in the command line.
For example: All Windows operating systems have a GUI.
Customer: People who go to live in a hotel while they are on a vacation or stay-cation.
Hotelier: They are owners of the hotel who had initially invested money and now share in its profits.
Hotel Management Staff: People who work in a hotel to earn livelihood and are concerned with the day to day activities of the hotel.
Bookings: These refer to services which are blocked and paid for by the customers for a certain number of hours for their leisure or entertainment.
For example: A customer can book a service like gym for 2 hours.
Reservations: These refer to rooms which are blocked and paid for by the customers for a certain number of days so that they can have an enjoyable stay in the hotel.
For example : A customer can reserve a room for 3 days.
Mainstream OS: Windows, Linux, Unix, OS-X

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. Launch and Shutdown

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. Customers

G.2.1. Adding a customer

Adding a customer with the add-customer command.
1. Test case: add-customer
  Expected: No customer is added. Error details shown in the status message. Status bar remains the same.
2. Other incorrect commands to try: addcustomer n/test name, addcustomer n/123 456…
3. Test case: add-customer … followed by the details of an existing customer
  Expected: No customer is added. Message shows "This customer already exists in the hms book". Status bar remains the same.

G.2.2. Deleting a customer

Deleting a customer while all customers are listed.
1. Prerequisites: List all customers using the list-customers command. Multiple customers in the list or at least 1.
2. Test case: delete-customer 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-customer 0
  Expected: No customer is deleted. Error details shown in the status message. Status bar remains the same.
4. Other incorrect delete commands to try: delete-customer, delete-customer x (where x is larger than the list size)…
  Expected: Similar to previous.

G.3. Reservations

G.3.1. Adding a reservation

Adding a reservation with the add-reservation command

Test case: add-reservation
Expected: No reservation is added. Error details shown in the status message. Status bar remains the same.
Other incorrect commands to try: add-reservation r/room-type, add-reservation r/room-type $/1…
Test case: add-reservation d/5/5/19 - 4/5/19 … followed by the remaining details+ Expected: No reservation is added. Error details regarding the date range are shown. Status bar remains the same. ..Other incorrect commands to try: add-reservation d/5/5/1 - 4/5/19 …, add-reservation d/5/13/19 - 4/5/19 …

G.3.2. Editing a reservation

=Editing a reservation with the edit-reservation command

Test case: edit-reservation
Expected: No reservation is edited. Error details shown in the status message. Status bar remains the same.
Test case: edit-reservation 1 r/INVALID_ROOM_TYPE $/-1
Expected: No reservation is edited. Error details shown in the status message. Status bar remains the same.
Other incorrect commands to try: edit-reservation 1 r/SINGLE ROOM $/1000, edit-reservation 1 r/SINGLE ROOM c/-1 c/1000
Test case: edit-reservation 1 d/5/5/19 - 4/5/19 … followed by the remaining details+ Expected: No reservation is edited. Error details regarding the date range are shown. Status bar remains the same.

G.3.3. Listing reservations

Listing all reservations with the list-reservation command

Test case: list=reservations
Expected: All reservations are listed. Timestamp in the status bar is updated.

G.3.4. Deleting a reservation

Deleting a reservation while all reservations are listed

Prerequisites: List all reservations using the list-reservations command. Multiple reservations in the list.
Test case: delete-reservation 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.
Test case: delete-reservation 0
Expected: No reservation is deleted. Error details shown in the status message. Status bar remains the same.
Other incorrect delete commands to try: delete-reservation, delete-reservation x (where x is larger than the list size)…
Expected: Similar to previous.

G.4. Bookings

G.4.1. Adding a booking

Adding a booking with the add-booking command

Test case: add-booking
Expected: No booking is added. Error details shown in the status message. Status bar remains the same.
Other incorrect commands to try: add-booking s/service-type, add-booking s/service-type $/1…
Test case: add-booking d/5/5/19 - 4/5/19 … followed by the remaining details+ Expected: No booking is added. Error details regarding the date range are shown. Status bar remains the same. ..Other incorrect commands to try: add-booking d/5/5/1 - 4/5/19 …, add-booking d/5/13/19 - 4/5/19 …

G.4.2. Editing a booking

=Editing a booking with the edit-booking command

Test case: edit-booking
Expected: No booking is edited. Error details shown in the status message. Status bar remains the same.
Test case: edit-booking 1 s/INVALID_SERVICE_TYPE $/-1
Expected: No booking is edited. Error details shown in the status message. Status bar remains the same.
Other incorrect commands to try: edit-booking 1 s/GYM $/1000, edit-booking 1 s/GYM c/-1 c/1000
Test case: edit-booking 1 :/22 - 25 … followed by the remaining details+ Expected: No booking is edited. Error details regarding the time range are shown. Status bar remains the same.

G.4.3. Listing bookings

Listing all bookings with the list-booking command

Test case: list=bookings
Expected: All bookings are listed. Timestamp in the status bar is updated.

G.4.4. Deleting a booking

Deleting a booking while all bookings are listed

Prerequisites: List all bookings using the list-bookings command. Multiple bookings in the list.
Test case: delete-booking 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.
Test case: delete-booking 0
Expected: No booking is deleted. Error details shown in the status message. Status bar remains the same.
Other incorrect delete commands to try: delete-booking, delete-reservation x (where x is larger than the list size)…
Expected: Similar to previous.

G.5. Service Types

G.5.1. Adding a service Type

Adding a service Type with the add-service-type command

Test case: add-service-type
Expected: No service type is added. Error details shown in the status message. Status bar remains the same.
Other incorrect commands to try: add-service-type n/name cap/-1…
Test case: add-service-type :/23 - 25 … followed by the remaining details+ Expected: No service type is added. Error details regarding the time range are shown. Status bar remains the same.

G.5.2. Editing a service type

=Editing a service type with the edit-service-type command

Test case: edit-service-type
Expected: No service type is edited. Error details shown in the status message. Status bar remains the same.
Test case: edit-service-type 1 rate/-1
Expected: No service type is edited. Error details shown in the status message. Status bar remains the same.
Other incorrect commands to try: edit-service-type 1 cap/-1, edit-service-type rate/-2
Test case: edit-service-type 1 :/22 - 25 … followed by the remaining details+ Expected: No service type is edited. Error details regarding the time range are shown. Status bar remains the same.

G.5.3. Deleting a service type

Deleting a service type while all service types are listed

Test case: delete-service-type 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.
Test case: delete-service-type 0
Expected: No service type is deleted. Error details shown in the status message. Status bar remains the same.
Other incorrect delete commands to try: delete-service-type, delete-reservation x (where x is larger than the list size)…
Expected: Similar to previous.

G.6. Room Types

G.6.1. Adding a room Type

Adding a room Type with the add-room-type command

Test case: add-room-type
Expected: No room type is added. Error details shown in the status message. Status bar remains the same.
Other incorrect commands to try: add-room-type n/name cap/-1…

G.6.2. Editing a room type

=Editing a room type with the edit-room-type command

Test case: edit-room-type
Expected: No room type is edited. Error details shown in the status message. Status bar remains the same.
Test case: edit-room-type 1 rate/-1
Expected: No room type is edited. Error details shown in the status message. Status bar remains the same.
Other incorrect commands to try: edit-room-type 1 cap/-1, edit-room-type rate/-2

G.6.3. Deleting a room type

Deleting a room type while all room types are listed

Test case: delete-room-type 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.
Test case: delete-room-type 0
Expected: No room type is deleted. Error details shown in the status message. Status bar remains the same.
Other incorrect delete commands to try: delete-room-type, delete-reservation x (where x is larger than the list size)…
Expected: Similar to previous.

G.7. Bill

G.7.1. Generating bill for a customer

Generating total bill for a customer based on index.
1. Prerequisites: At-least one customer who has at-least one booking or reservation in the database.
2. Test case: gb-c
  Expected: Bill is not generated. Error details shown in the status message. Status bar remains the same.
3. Test case: gb-c 1
  Expected: Bill is generated for customer at index 1. The respective status message is displayed. Timestamp in the status bar is updated.
4. Other incorrect generate bill for customer commands to try: gbc, g-b-c, gb-c x (where x is larger than the list size)..
  Expected: Bill is not generated. Error details shown in the status message. Status bar remains the same.

G.8. Generating booking bill for a customer.

Generating booking bill for a customer based on index, or service type, or booking hours.
1. Prerequisites: At-least one customer who has at least one booking in the database.
2. Test case: gb-b
  Expected: Bill is not generated. Error details shown in the status message. Status bar remains the same.
3. Test case: gb-b 1
  Expected: Bill is generated for customer at index 1. The respective status message is displayed. Timestamp in the status bar is updated.
4. Test case: gb-b 1 s/GYM
  Expected: Bill is generated for customer at index 1. The respective status message is displayed. Timestamp in the status bar is updated.
5. Other incorrect generate bill for customer commands to try: gbb, g-b-b, gb-b x (where x is larger than the list size)..
  Expected: Bill is not generated. Error details shown in the status message. Status bar remains the same.

G.9. Switching tab

Switching tabs in the application.
1. Test case: st 1 2
  Expected : Switches to Reservation tab in first panel and the appropriate message is displayed. Status bar remains the same.
2. Test case: st 1 0
  Expected : No switch is made. Error details shown in the status message. Status bar remains the same.
3. Other incorrect switch tab commands to try: st, st 1, st 1 2 3 …
  Expected: Similar to previous.

HMS+ - Developer Guide

How the architecture components interact with each other

Logic component

Model component

Ui component

Storage component

Use case: Add reservation

Use case: Edit reservation

Use case: List reservations

Use case: Delete reservation

Use case: Add booking

Use case: Edit booking

Use case: List bookings

Use case: Delete booking

Use case: Add room-type

Use case: Edit room-type

Use case: Delete room-type

Use case: Add service

Use case: Edit service

Use case: Delete service

Use case: Generate booking bill for a specific customer

Use case: Finding the specific list of bookings

Use case: Finding the specific list of reservations

Use case: Clear all reservations

Use case: Clear all bookings

`Logic` component

`Model` component

`Ui` component

`Storage` component