PROJECT: Pet Store Helper

Overview

Pet Store Helper (PSH) is a desktop application used for pet store owners to manage different aspects of their pet store including pet logging, scheduling and inventory management. The user interacts with it using a CLI, and it has a GUI created with JavaFX. It is written in Java, and has about 15k LOC.

Summary of contributions

  • Major enhancement: added the ability to back up/load app data

    • What it does: allows the user to back up the current state of the app and load app data from any compatible JSON file

    • Justification: This feature improves the product significantly because a store should maintain backups of their system files so that data can be recovered in case of a system failure. It is also important to retain past data so that they can be extracted for analysis in the future.

    • Highlights: This enhancement does not affect existing commands, allowing it to integrate seamlessly with the rest of the app. However, this is reliant on the fact that currently the commands are only affected by the data of the app. If an undo/redo command is added, past and undone commands would also need to be saved to avoid errors arising from mismatch of commands and app data.

    • Credits: Code from Address Book Level 4 was referenced to set up temporary files for testing.

  • Minor enhancement: Updated Storage to allow saving of new/refactored classes to JSON format.

  • Code contributed: [Reposense]

  • Other contributions: Refactored Storage package and tests for Logic package

    • Project management:

      • Managed releases v1.2.1 and v1.3.3 (2 releases) on GitHub

    • Enhancements to existing features:

      • Wrote additional tests for new JSON-adapted classes to maintain coverage (Pull requests #21, #83)

    • Documentation:

      • Did cosmetic tweaks to existing contents of the Developer Guide: #90 (mainly adjusting the UML diagrams and removing references to AB3)

    • Community:

      • PRs reviewed (with non-trivial review comments): #134, #144

      • Contributed to forum discussions (examples: 1, 2, 3)

    • Tools:

      • Integrated multiple new Github plugins (AppVeyor, Coveralls, CircleCI and Netlify) to the team repo

Contributions to the User Guide

Given below are sections I contributed to the User Guide. They showcase my ability to write documentation targeting end-users.

Back Up and Load

The back up and load commands together allow data to be stored and managed directly.

Back up

To back up the current state of the pet store, enter the backup command.

The file name is generated based on the current date and time and reported back.

It is stored in the same directory as the default data file.

backup

Load

To load a file, enter the load command followed by the file name.

The file should be stored in the same directory as the default data file.

For example, after removing a few pets and slots, the screen will be different from when we backed up previously.

load1

In this case, entering load 20200413_20_23_57 restores the system to its backed-up state.

load2

The file name can be any valid file name under the curent operating system and need not conform to the backup file naming scheme.

Contributions to the Developer Guide

Given below are sections I contributed to the Developer Guide. They showcase my ability to write technical documentation and the technical depth of my contributions to the project.

Storage component

Written by Chen Shenghao

StorageClassDiagram
Figure 1. Structure of the Storage Component

The Storage component,

  • can save UserPref objects in json format and read it back.

  • can save the Pet Tracker data in json format and read it back.

Back up and load feature

Written by Chen Shenghao

Implementation

The back up/load mechanism is facilitated by Storage.

Storage is extended to implement the following operations:

  • savePetTracker#(ReadOnlyPetTracker, LocalDateTime) — calls savePetTracker#(ReadOnlyPetTracker, Path) after converting LocalDateTime to Path

  • savePetTracker#(ReadOnlyPetTracker, Path) — saves pet tracker data to specified path

The back up/load mechanism follows the exact same steps taken when data is saved after each operation and read at initialization. This ensures maximum compatibility and reduces the need for additional code.

backup should never fail unless the saving of data after every operation also fails. For 'load', there are two additional caveats, the specified file should exist and be in the correct format. This is unlike the reading of data at initialization which simply resorts to an empty file instead if these issues occur.

The following sequence diagram shows how the backup operation works:

BackUpSequenceDiagram

The following sequence diagram shows how the load operation works:

LoadSequenceDiagram

Design Considerations

Aspect: How back up & load executes

  • Alternative 1 (current choice): Executed by Command, following general pattern for Command

    • Pros: Easy to implement, able to rely on established pattern for Command.

    • Cons: Storage is exposed to classes in the parser package, which should not have access to its methods

  • Alternative 2: Executed by LogicManager, which already saves data to hard disk after every operation

    • Pros: Storage does not have to be passed to classes in the parser package

    • Cons: Requires passing instruction back to LogicManager, actual operation performed after end of Command#execute(), unable to obtain reliable success/error message.

PROJECT: RTOS-Based Robotic Car

Under a computer engineering module, I am also currently involved in the development of RTOS-based software that allows a robotic car to be controlled for maze navigation via an Android app.