AB-3 Developer Guide

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Acknowledgements

{ list here sources of all reused/adapted ideas, code, documentation, and third-party libraries -- include links to the original source as well }

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Setting up, getting started

Refer to the guide Setting up and getting started.

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Design

Architecture

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

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

Main components of the architecture

Main (consisting of classes Main and MainApp) is in charge of the app launch and shut down.

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

The bulk of the app's work is done by the following four components:

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

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

How the architecture components interact with each other

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

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

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

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

The sections below give more details of each component.

UI component

The API of this component is specified in Ui.java

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

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

The UI component,

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

Logic component

API : Logic.java

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

The sequence diagram below illustrates the interactions within the Logic component, taking execute("delete 1") API call as an example.

How the Logic component works:

1. When Logic is called upon to execute a command, it is passed to an AddressBookParser object which in turn creates a parser that matches the command (e.g., DeleteCommandParser) and uses it to parse the command.
2. This results in a Command object (more precisely, an object of one of its subclasses e.g., DeleteCommand) which is executed by the LogicManager.
3. The command can communicate with the Model when it is executed (e.g. to delete a person).
   Note that although this is shown as a single step in the diagram above (for simplicity), in the code it can take several interactions (between the command object and the Model) to achieve.
4. The result of the command execution is encapsulated as a CommandResult object which is returned back from Logic.

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

How the parsing works:

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

Model component

API : Model.java

The Model component,

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

Storage component

API : Storage.java

The Storage component,

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

Common classes

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

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Implementation

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

[Proposed] Undo/redo feature

Proposed Implementation

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

• VersionedAddressBook#commit() — Saves the current address book state in its history.
• VersionedAddressBook#undo() — Restores the previous address book state from its history.
• VersionedAddressBook#redo() — Restores a previously undone address book state from its history.

These operations are exposed in the Model interface as Model#commitAddressBook(), Model#undoAddressBook() and Model#redoAddressBook() respectively.

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

Step 1. The user launches the application for the first time. The VersionedAddressBook will be initialized with the initial address book state, and the currentStatePointer pointing to that single address book state.

Step 2. The user executes delete 5 command to delete the 5th person in the address book. The delete command calls Model#commitAddressBook(), causing the modified state of the address book after the delete 5 command executes to be saved in the addressBookStateList, and the currentStatePointer is shifted to the newly inserted address book state.

Step 3. The user executes add n/David …​ to add a new person. The add command also calls Model#commitAddressBook(), causing another modified address book state to be saved into the addressBookStateList.

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

The following sequence diagram shows how an undo operation goes through the Logic component:

Similarly, how an undo operation goes through the Model component is shown below:

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

Step 5. The user then decides to execute the command list. Commands that do not modify the address book, such as list, will usually not call Model#commitAddressBook(), Model#undoAddressBook() or Model#redoAddressBook(). Thus, the addressBookStateList remains unchanged.

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

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

Design considerations:

Aspect: How undo & redo executes:

• Alternative 1 (current choice): Saves the entire address book.

  • Pros: Easy to implement.
  • Cons: May have performance issues in terms of memory usage.

• Alternative 2: Individual command knows how to undo/redo by itself.

  • Pros: Will use less memory (e.g. for delete, just save the person being deleted).
  • Cons: We must ensure that the implementation of each individual command are correct.

{more aspects and alternatives to be added}

[Proposed] Data archiving

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

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Documentation, logging, testing, configuration, dev-ops

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

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Appendix: Requirements

Product scope

Target user profile:

• is a property agent with many different kinds of contacts
• has a need to manage a big number of contacts
• has a need to track information about each contact
• has a need to categorize different contacts
• prefer desktop apps over other types
• is a fast typist, preferring typing to mouse interactions
• is comfortable using CLI apps

Value proposition: manage and organise different kinds of contacts and their information faster than a typical mouse/GUI driven app

User stories

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

Use cases

(For all use cases below, the System is the 'TrackerGuru' and the Actor is the 'Property Agent', unless specified otherwise. The term 'User' will be synonymous to 'Property Agent')

Use case: UC1 - Add a contact

Guarantees

• The address book will not contain duplicate contacts after any operation.
• If the contact is added, all contact details provided by the user will be stored without any loss of information.

MSS

1. User requests to add a contact together with their relevant details.

2. TrackerGuru saves the contact and its details.

3. TrackerGuru displays a success message to the user.

   Use case ends.

Extensions

• 1a. TrackerGuru detects an error in the entered data (missing required fields or improper format).

  • 1a1. TrackerGuru displays an error message and the proper command format to the user.
    Use case resumes from step 1.

• 1b. TrackerGuru detects a duplicate contact (same phone number).

  • 1b1. TrackerGuru requests confirmation to overwrite or abort.
  • 1b2. User chooses to overwrite → TrackerGuru updates the contact and displays a success message.
  • 1b3. User chooses to abort → Use case ends.

• 1c. TrackerGuru fails to save the contact due to a system error.

  • 1c1. TrackerGuru displays an error message.
    Use case ends.

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Use case: UC2 - Delete a contact

MSS

1. User requests to delete a contact.

2. TrackerGuru deletes the contact.

3. TrackerGuru displays a success message to the user.

   Use case ends.

Extensions

• 1a. TrackerGuru detects that the contact’s unique identifier is missing in the entered data.

  • 1a1. TrackerGuru requests for the contact’s unique identifier.
    Use case resumes from step 1.

• 1b. TrackerGuru cannot find the specified contact’s unique identifier.

  • 1b1. TrackerGuru requests for a valid unique identifier.
  • 1b2. User enters a new unique identifier.
    Steps 1b1–1b2 are repeated until the unique identifier is one that exists.
    Use case resumes from step 2.

• 1c. TrackerGuru fails to delete the contact due to a system error.

  • 1c1. TrackerGuru informs the user.
    Use case ends.

• *a. At any time, User chooses to cancel the deletion request.
  Use case ends.

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Use case: UC3 - Tag contact with role

Guarantees

• Role tags associated with updated contacts will be of a valid role type (buyer, seller, ...).

MSS

1. User requests to tag a contact with a role.

2. TrackerGuru saves the contact with its updated tags (existing tags are not overridden).

3. TrackerGuru displays a success message to the user.

   Use case ends.

Extensions

• 1a. TrackerGuru detects an error in the entered data (role type entered by user is invalid).

  • 1a1. TrackerGuru displays an error message and available role types to the user.
    Use case resumes from step 1.

• 1b. TrackerGuru fails to save the updated contact due to a system error.

  • 1b1. TrackerGuru displays an error message.
    Use case ends.

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Use case: UC4 - Search contact by name

Guarantees

• Only contacts whose names match the given keywords will be displayed to the user (if MSS completes).
• Contact details will not be modified.

MSS

1. User requests for contacts whose name matches the given keywords.

2. TrackerGuru displays all matching contacts.

3. TrackerGuru displays a success message to the user.

   Use case ends.

Extensions

• 1a. TrackerGuru detects an error in the entered data (missing required fields or improper format).

  • 1a1. TrackerGuru displays an error message and proper command format to the user.
    Use case resumes from step 1.

• 1b. TrackerGuru fails to search contacts due to a system error.

  • 1b1. TrackerGuru displays an error message.
    Use case ends.

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Use case: UC-5 Edit a contact

Guarantees

• Existing contact information will be updated to the address book only if MSS completes.
• All the fields in the contact will be of valid type.

MSS

1. User requests to edit contact with together with their relevant details.

2. System edits and saves the updated contact information.

3. System displays success message to the user.

4. System's contact list reflects the updated contact information.

   Use case ends.

Extensions

• 1a. System detects an error in the entered data (invalid index).

  • 1a1. System displays error message that the specified index is invalid.

    Use case resumes from step 1.

• 2a. System fails to edit the contact information due to a system error.

  • 2a1. System displays an error message indicating the failure.

    Use case ends.

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Use case: UC-6 Sort contacts

Guarantees

• The contact list remains intact with no data lost or modified.
• The contact list will be displayed in the specified sorted order.

MSS

1. User requests to sort the contact list.

2. System sorts the contact list based on the specified criterion.

3. System displays the sorted contact list.

   Use case ends.

Extensions

• 1a. System detects an error in the entered data (invalid or missing sorting criterion).

  • 1a1. System displays an error message indicating that the criterion is invalid or missing.

    Use case resumes from step 1.

• 2a. System fails to sort the contacts due to a system error.

  • 2a1. System displays an error message indicating the failure.

    Use case ends.

Non-Functional Requirements

Performance/Capacity requirements

• The system should be able to store up to 200 contacts at once
• The system should load and display contact lists within 2 seconds, even at maximum capacity
• The system should boot within 3 seconds on a computer with at least 8GB RAM and an Intel Core i5/Ryzen 5-class processor (or equivalent)

Technical requirements

• The system should work on any computer that runs Java 17
• The system should not have a remote server
• The system should be functional without internet connection
• The system should only use local storage to store contacts
• The system should support using a local .json file to store and retrieve contact data

Reliability requirements

• The system should not lose saved data in the event of unexpected termination

Security requirements

• The system should not transmit contact data over the internet

Maintainability requirements

• The code should be modular and well documented
• The system should allow adding new contact fields without major refactoring

Quality requirements

• The system should provide help and usage instructions
• Command syntax should be consistent and documented
• All operations can be completed in no more than one typed line
• The system should display clear error messages for invalid inputs instead of crashing

Glossary

• client: A specific kind of contact that represents customers of the property agent (i.e. property buyers, sellers, landlords, tenants)
• contact information: Exact contact details of a person; name, phone number, email, address
• contact tags: Labels or categories used to group contacts
• role: A field that defines the function or relationship of a contact (e.g. buyer, seller, landlord, tenant) in the property business
• status: A label indicating the current state of a client transaction (e.g. looking to sell, looking to buy, signing).
• property size: A label describing the size of a property in sqft that the client is offering/looking for
• property type: A label describing the type of property that the client is offering/looking for (e.g. studio, terrace, hdb)
• property location: A label specifying the geographical area of a property that the client is offering/looking for (e.g. Bishan, Woodlands)

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Appendix: Instructions for manual testing

Given below are instructions to test the app manually.

Launch and shutdown

1. Initial launch

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

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

2. Saving window preferences

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

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

3. { more test cases …​ }

Deleting a person

1. Deleting a person while all persons are being shown

   1. Prerequisites: List all persons using the list command. Multiple persons in the list.

   2. Test case: delete 1
      Expected: First contact is deleted from the list. Details of the deleted contact shown in the status message. Timestamp in the status bar is updated.

   3. Test case: delete 0
      Expected: No person is deleted. Error details shown in the status message. Status bar remains the same.

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

2. { more test cases …​ }

Saving data

1. Dealing with missing/corrupted data files

   1. {explain how to simulate a missing/corrupted file, and the expected behavior}

2. { more test cases …​ }