Developer Guide

• Acknowledgements
• Introduction
• Setting up, getting started
• Design
  • Architecture
  • UI component
  • Logic component
  • Model component
  • Storage component
  • Common classes
• Implementation
  • Select an activity
    • Implementation
  • Renaming commands
    • Implementation
    • Design Considerations
  • Setting activity status
    • Implementation
  • Rating and reviewing an activity
    • Implementation
  • Setting Themes
    • Implementation
    • Design Considerations
  • [Proposed] Undo/redo feature
    • Proposed Implementation
    • Design considerations:
• Documentation, logging, testing, configuration, dev-ops
• Appendix: Requirements
  • Product scope
  • User stories
  • Use cases
  • Non-Functional Requirements
  • Glossary
• Appendix: Instructions for manual testing
  • Launch and shutdown
  • Deleting an activity
  • Saving data

---

Acknowledgements

• The implementation of the status field is adapted from this project’s implementation of a similar feature.
• The code for the removal of bullet points from the User Guide’s table of content is reused from AY2021S1-CS2103T-W16-3’s PR #179 and PR #190.
• HobbyList’s User Guide is adapted from AB-3’s User Guide.
• HobbyList’s Developer Guide is adapted from AB-3’s Developer Guide.

---

Introduction

HobbyList is a desktop app for students to manage their hobby activities, optimized for use via a Command Line Interface (CLI) while still having the benefits of a Graphical User Interface (GUI). If you can type fast, HobbyList can get your activity management tasks done faster than traditional GUI apps.

---

Setting up, getting started

Refer to the guide Setting up and getting started.

---

Design

Architecture

The Architecture Diagram given above explains the high-level design of the App.

Given below is a quick overview of main components and how they interact with each other.

Main components of the architecture

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

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

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

The rest of the App consists of four components.

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

How the architecture components interact with each other

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

Each of the four main components (also shown in the diagram above),

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

For example, the Logic component defines its API in the Logic.java interface and implements its functionality using the LogicManager.java class which follows the Logic interface. Other components interact with a given component through its interface rather than the concrete class (reason: to prevent outside component’s being coupled to the implementation of a component), as illustrated in the (partial) class diagram below.

The sections below give more details of each component.

UI component

The API of this component is specified in Ui.java

The UI consists of a MainWindow that is made up of parts e.g.CommandBox, ResultDisplay, ActivityListPanel, StatusBarFooter etc. All these, including the MainWindow, inherit from the abstract UiPart class which captures the commonalities between classes that represent parts of the visible GUI.

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

The UI component,

• executes user commands using the Logic component.
• listens for changes to Model data so that the UI can be updated with the modified data.
• keeps a reference to the Logic component, because the UI relies on the Logic to execute commands.
• depends on some classes in the Model component, as it displays Activity object residing in the Model.

Logic component

API : Logic.java

Here’s a (partial) class diagram of the Logic component:

How the Logic component works:

1. When Logic is called upon to execute a command, it uses the HobbyListParser class to parse the user command.
2. This results in a Command object (more precisely, an object of one of its subclasses e.g., AddCommand) which is executed by the LogicManager.
3. The command can communicate with the Model when it is executed (e.g. to add an activity).
4. The result of the command execution is encapsulated as a CommandResult object which is returned back from Logic.

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

Here are the other classes in Logic (omitted from the class diagram above) that are used for parsing a user command:

How the parsing works:

• When called upon to parse a user command, the HobbyListParser class creates an XYZCommandParser (XYZ is a placeholder for the specific command name e.g., AddCommandParser) which uses the other classes shown above to parse the user command and create a XYZCommand object (e.g., AddCommand) which the HobbyListParser returns back as a Command object.
• All XYZCommandParser classes (e.g., AddCommandParser, DeleteCommandParser, …) inherit from the Parser interface so that they can be treated similarly where possible e.g, during testing.

Model component

API : Model.java

The Model component,

• stores the activity list data i.e., all Activity objects (which are contained in a UniqueActivityList object).
• stores the currently ‘selected’ Activity objects (e.g., results of a search query) as a separate filtered list which is exposed to outsiders as an unmodifiable ObservableList<Activity> that can be ‘observed’ e.g. the UI can be bound to this list so that the UI automatically updates when the data in the list change.
• stores a UserPref object that represents the user’s preferences. This is exposed to the outside as a ReadOnlyUserPref objects.
• does not depend on any of the other three components (as the Model represents data entities of the domain, they should make sense on their own without depending on other components)

Storage component

API : Storage.java

The Storage component,

• can save both activity list data and user preference data in json format, and read them back into corresponding objects.
• inherits from both HobbyListStorage and UserPrefStorage, which means it can be treated as either one (if only the functionality of only one is needed).
• depends on some classes in the Model component (because the Storage component’s job is to save/retrieve objects that belong to the Model)

Common classes

Classes used by multiple components are in the hobbylist.commons package.

---

Implementation

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

Select an activity

Implementation

The following sequence diagram shows what happens when the user selects an activity by its Index from the activity list.

The activity with the given Index is selected and kept tracked by a listener of so that SelectedActivityPanel can be updated whenever there are changes to the currently selected activity.

The following sequence diagram shows what happens in the UI when the selected activity gets deleted.

Renaming commands

Implementation

Storing of renamed commands is facilitated by AliasSettings. It is an attribute of UserPrefs. It contains a string for each of the commands implemented. It extends Serializable so it can be converted into json for storage.

A new window, EditAliasesWindow is also added to provide a place to edit the names of all the commands.

The following sequence diagram shows what happens when the user saves a new set of command names.

The command word for each command is updated and all future commands are parsed with the new command words.

The following sequence diagram shows what happens in the model component when setAliasSettings() is called.

Design Considerations

Aspect: How to store the list of command names:

• Alternative 1 (current choice): Save it in a variable corresponding to the command.
  • Pros: Easy to implement.
  • Cons: Hard to extend when new commands are added.
• Alternative 2: Use a list of commands and dynamically generate the fields in EditAliasesWindow and store the changed command names using a HashMap.
  • Pros: Easy to extend.
  • Cons: Harder to implement.

Setting activity status

The user can set status for an activity by including s/STATUS when performing the add or edit command.

• s/STATUS only accepts UPCOMING, ONGOING or COMPLETED as STATUS (case-insensitive).
• If STATUS is not specified when performing the add command, it will be displayed as STATUS: NONE by default.
• Different status will have different coloured tag when displayed in the list of activities.

The addition of the status field allows the user to categorise their activities into different status. This way it will be easier for the user to check their upcoming, ongoing or completed activities so that they can properly track their progress and plan their schedule.

Implementation

Similar to the existing Name field, the implementation of the Status field is achieved by creating a Status class and letting the Activity class take in a status object.

The following is a scenario of when the user wants to add an activity named “Star Wars”, with the description “movie” and with a status of “upcoming”.

1. execute("add n/Star Wars d/movie s/upcoming") of LogicManager calls the parseCommand method of HobbyListParser
2. parseCommand("add n/Star Wars d/movie s/upcoming") parses the string "add n/Star Wars d/movie s/upcoming" and calls the parse method of AddCommandParser
3. The parse method will check if the name, description and status provided are valid. If it is valid, it returns a new AddCommand object.
4. The overridden execute method from AddCommand is then called which adds the created activity object to the model and return a new CommandResult object.

The following sequence diagram shows what happens when the user perform add n/Star Wars d/movie s/upcoming.

Rating and reviewing an activity

Implementation

The command is parsed and a RateCommand is created. Executing the RateCommand then creates a new activityWithRating Activity with the rate and/or review fields and set the old activity to activityWithRating.

The following sequence diagram shows what happens when the user uses a rate command.

Setting Themes

Implementation

Changing themes is handled by 5 different methods. Each comes with a unique css file.

Each css file applies a set of different stylesheets to MainWindow, ActivityCard, ActivityListPanel, CommandBox and ResultDisplay.

The following sequence diagram shows what happens when the user decide to change a theme. Take change the theme to Dark as an example.

Design Considerations

Aspect: How to prevent adding multiple stylesheets to the scene:

Current choice: Remove all stylesheets and then add a new one.

Aspect: How to keep the user-preferred settings:

Current choice: Save it as a variable in MainWindow class and load it when next time user start the app.

[Proposed] Undo/redo feature

Proposed Implementation

The proposed undo/redo mechanism is facilitated by VersionedHobbyList. It extends HobbyList with an undo/redo history, stored internally as an hobbyListStateList and currentStatePointer. Additionally, it implements the following operations:

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

These operations are exposed in the Model interface as Model#commitHobbyList(), Model#undoHobbyList() and Model#redoHobbyList() 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 VersionedHobbyList will be initialized with the initial activity list state, and the currentStatePointer pointing to that single activity list state.

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

Step 3. The user executes add n/Run 42km …​ to add a new activity. The add command also calls Model#commitHobbyList(), causing another modified activity list state to be saved into the hobbyListStateList.

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

The following sequence diagram shows how the undo operation works:

The redo command does the opposite — it calls Model#redoHobbyList(), which shifts the currentStatePointer once to the right, pointing to the previously undone state, and restores the activity list to that state.

Step 5. The user then decides to execute the command list. Commands that do not modify the activity list, such as list, will usually not call Model#commitHobbyList(), Model#undoHobbyList() or Model#redoHobbyList(). Thus, the hobbyListStateList remains unchanged.

Step 6. The user executes clear, which calls Model#commitHobbyList(). Since the currentStatePointer is not pointing at the end of the hobbyListStateList, all activity list states after the currentStatePointer will be purged. Reason: It no longer makes sense to redo the add n/Run 42km …​ command. This is the behavior that most modern desktop applications follow.

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

Design considerations:

Aspect: How undo & redo executes:

• Alternative 1 (current choice): Saves the entire activity list.
  • 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 activity being deleted).
  • Cons: We must ensure that the implementation of each individual command are correct.

{more aspects and alternatives to be added}

---

Documentation, logging, testing, configuration, dev-ops

• Documentation guide
• Testing guide
• Logging guide
• Configuration guide
• DevOps guide

---

Appendix: Requirements

Product scope

Target user profile:

• need to store all the past activities that are done
• keep track of ongoing and future activities
• keep record of time of certain event
• organize all the activities for better look up
• prefer desktop apps over other types
• can type fast
• prefers typing to mouse interactions
• is reasonably comfortable using CLI apps

Value proposition: Provide a place for our users to store all the activities that are done, ongoing or todo and organises it for them so it will be easier to trace back using specific activities. Mainly CLI with many shortcuts to benefit people who type fast.

User stories

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

Priority	As a …	I want to …	So that I can…
* * *	user	add activity	track my activities
* * *	user	delete activity	make mistakes
* * *	user	view activities	look at what I have done
* *	busy CS student	quickly write commands	save time adding entries
* *	busy CS student	add date to an activity	keep the timeline of events in life clear
*	busy CS student	find activities in certain time period	manage different timeline of activities
* *	new user	type “help” for help	try the commands and use the app
* *	new user	clear all activities	quickly clear the sample data
* *	new user	see sample data	get to know how the app works
* *	user	tag an activity with a type	know what type of activity it is
* *	user	change the appearance of the app	have better experience when looking through
* *	user	add an activity description	know what the activity is about
*	long time user	use shortcuts for commands	enter commands faster
*	food enthusiast	review restaurants	note down my opinions of the restaurant
*	food enthusiast	rate restaurants	note down my opinions of the restaurant
*	food enthusiast	find restaurants with certain rate	quickly choose a restaurant to go
*	food enthusiast	find restaurants with rate higher than or equal to a certain value	choose some restaurants to recommend to others
*	gym user	keep track of dates of activities	record when I did the activity
*	long time user	search activities with keywords	quickly find certain activity

{More to be added}

Use cases

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

Use case: UC01 - Add an activity

MSS

1. User requests to add an activity to the list

2. HobbyList adds that activity to the list and shows a confirmed message

   Use case ends.

Extensions

• 1a. The activity is already existed.

  • 1a1. HobbyList shows a message to announce the user.

    Use case ends.

Use case: UC02 - List all activities

MSS

1. User requests to see all activities

2. HobbyList shows a list of activities

   Use case ends.

Extensions

• 2a. The list is empty.

  • 2a1. HobbyList shows a message to announce the user.

    Use case ends.

Use case: UC03 - Delete an activity

MSS

1. User requests to list out all activities
2. HobbyList shows a list of activities
3. User requests to delete a specific activity in the list

4. HobbyList deletes the activity

   Use case ends.

Extensions

• 2a. The list is empty.

  Use case ends.

• 3a. The given index is invalid.

  • 3a1. HobbyList shows an error message.

    Use case resumes at step 2.

Use case: UC04 - Find activities in a certain time period

MSS

1. User find activities on a certain date/in a certain month/year.

2. HobbyList shows all the activities located in the required period.

   Use case ends.

Use case: UC05 - Find activities whose rating are greater or equal than certain value

MSS

1. User find activities with rates greater or equal than certain value.

2. HobbyList shows activities with rates above certain value.

   Use case ends.

Use case: UC06 - Add date of an activity

MSS

1. User add an activity with date

2. HobbyList shows the date in the activity card

   Use case ends.

Extensions

• 1a. The date format is wrong
  • 1a1. HobbyList shows a message about the right format.
• 1b. There are multiple dates in the add command

  • 1b1. HobbyList will save the last date typed in.

    Use case ends.

Use case: UC07 - Edit date of an activity

MSS

1. User edit an activity with new date

2. HobbyList update the date in the activity card

   Use case ends.

Extensions

• 1a. The edit content of date is empty

  • 1a1. HobbyList delete the original date.

    Use case ends.

Use case: UC08 - Select an activity to display its details

MSS

1. User select an activity by its index

2. HobbyList show all the details of the selected activity, including name, description, tags, date, status, rating, review

   Use case ends.

Extensions

• 1a. The given index is invalid

  • 1a1. HobbyList shows an error message.

    Use case resumes at step 1.

Use case: UC09 - Changing command names

MSS

1. User requests to change command names
2. HobbyList prompts the user for changes
3. User sets the changes and confirms

4. HobbyList saves the changes

   Use case ends.

Extensions

• 2a. User enters invalid command names

  • 2a1. HobbyList alerts user of the error

    Use case resumes at step 2.

Use case: UC10 - Changing to a different theme

MSS

1. User change a theme
2. HobbyList show the target theme

3. HobbyList saves the change as default ui for next time when user open the app.

   Use case ends.

Non-Functional Requirements

1. Should work on any mainstream OS as long as it has Java 11 or above installed.
2. Should be able to hold up to 1000 activities without a noticeable sluggishness in performance for typical usage.
3. A user with above average typing speed for regular English text (i.e. not code, not system admin commands) should be able to accomplish most of the tasks faster using commands than using the mouse.

{More to be added}

Glossary

Terms	Meaning
Mainstream OS	Windows, Linux, Unix, OS-X
GUI	A graphical user interface, which is the visual display you see when using HobbyList
Index	A number that you can use to refer to a particular activity
Tag	A word (eg. Entertainment, Sport) that you can attach to the activities to easily identify them
Date	A yyyy-mm-dd format date (eg. 2002-02-19) that you can attach to the activities for matching date

---

Appendix: Instructions for manual testing

Given below are instructions to test the app manually.

Launch and shutdown

1. Initial launch

   1. Download the jar file and copy into an empty folder

   2. Double-click the jar file Expected: Shows the GUI with a set of sample contacts. The window size may not be optimum.

2. Saving window preferences

   1. Resize the window to an optimum size. Move the window to a different location. Close the window.

   2. Re-launch the app by double-clicking the jar file.
      Expected: The most recent window size and location is retained.

Deleting an activity

1. Deleting an activity while all activities are being shown

   1. Prerequisites: List all activities using the list command. Multiple activities 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 activity is deleted. Error details shown in the status message. Status bar remains the same.

   4. Other incorrect delete commands to try: delete, delete x, ... (where x is larger than the list size)
      Expected: Similar to previous.

Saving data

1. Dealing with missing/corrupted data files

   1. Test case: delete a name field in the save file.
      Expected: Save file gets wiped.

   2. Test case: set an activity’s date to test.
      Expected: Save file gets wiped.

   3. Test case: set an activity’s status to test.
      Expected: Save file gets wiped.

   4. Test case: set an activity’s rating to test.
      Expected: Save file gets wiped.