muhammad-abdurrahman / java-backend-test

Spring Clean Application

To run the application run the following commands from the root directory of the application:

• Windows
  • .\mvnw.cmd clean install spring-boot:run
• OSX/Linux
  • ./mvnw clean install spring-boot:run

The application is run as a fat jar and is served on port 8080 by the embedded Tomcat Servlet container.

To execute the cleaning computation, send an Http POST request to http://localhost:8080/spring-cleaner/execute (the JSON payload for this request follows the specification below)

The server will respond with the output as well as persist the input and output in an in-memory database (h2) which can be accessed at the following url: http://localhost:8080/h2

To access the database please ensure the following at the H2 console login page:

• Driver Class: org.h2.Driver
• JDBC URL: jdbc:h2:mem:spring-clean
• User Name: user
• Password: [leave blank]

The data model consists of 5 tables:

• spring_clean
• input
• output
• input_patches
• coordinate

The spring_clean table contains foreign keys to the inputs and outputs.

The input_patches table is a weak entity between input and coordinate table representing a many-to-many relationship.

The project uses lombok (https://projectlombok.org/) thus in order for your IDE to recognise this, please ensure you install the respective lombok plugin. This can be obtained from the lombok website.

Introduction

You will write a com.yoti.springcleaning.service that navigates a imaginary robotic hoover (much like a Roomba) through an equally imaginary room based on:

• room dimensions as X and Y coordinates, identifying the top right corner of the room rectangle. This room is divided up in a grid based on these dimensions; a room that has dimensions X: 5 and Y: 5 has 5 columns and 5 rows, so 25 possible hoover positions. The bottom left corner is the point of origin for our coordinate system, so as the room contains all coordinates its bottom left corner is defined by X: 0 and Y: 0.
• locations of patches of dirt, also defined by X and Y coordinates identifying the bottom left corner of those grid positions.
• an initial hoover position (X and Y coordinates like patches of dirt)
• driving instructions (as cardinal directions where e.g. N and E mean "go north" and "go east" respectively)

The room will be rectangular, has no obstacles (except the room walls), no doors and all locations in the room will be clean (hoovering has no effect) except for the locations of the patches of dirt presented in the program input.

Placing the hoover on a patch of dirt ("hoovering") removes the patch of dirt so that patch is then clean for the remainder of the program run. The hoover is always on - there is no need to enable it.

Driving into a wall has no effect (the robot skids in place).

Goal

The goal of the com.yoti.springcleaning.service is to take the room dimensions, the locations of the dirt patches, the hoover location and the driving instructions as input and to then output the following:

• The final hoover position (X, Y)
• The number of patches of dirt the robot cleaned up

Input

Program input will be received in a json payload with the format described here.

Example:

{
  "roomSize" : [5, 5],
  "coords" : [1, 2],
  "patches" : [
    [1, 0],
    [2, 2],
    [2, 3]
  ],
  "instructions" : "NNESEESWNWW"
}

Output

Service output should be returned as a json payload.

Example (matching the input above):

{
  "coords" : [1, 3],
  "patches" : 1
}

Where coords are the final coordinates of the hoover and patches is the number of cleaned patches. Moreover, the services persists every input and output to a database.

Deliverable

The com.yoti.springcleaning.service:

• is a web com.yoti.springcleaning.service
• must run on Mac OS X or Linux (x86-64)
• must be written in Java
• can make use of any existing open source libraries that don't directly address the problem statement (use your best judgement).

Send us:

• The full source code, including any code written which is not part of the normal program run (scripts, tests)
• Clear instructions on how to obtain and run the program
• Please provide any deliverables and instructions using a public Github (or similar) Repository as several people will need to inspect the solution

Evaluation

The point of the exercise is for us to see some of the code you wrote (and should be proud of).

We will especially consider:

• Code organisation
• Quality
• Readability
• Actually solving the problem

This test is based on the following gist https://gist.github.com/alirussell/9a519e07128b7eafcb50