rsilva4-zz/vending-machine

Vending Machine exercise

Design a vending machine using a programming language of your choice. The vending machine should perform as follows:

• Once an item is selected and the appropriate amount of money is inserted, the vending machine should return the correct product.
• It should also return change if too much money is provided, or ask for more money if insufficient funds have been inserted.
• The machine should take an initial load of products and change. The change will be of denominations 1p, 2p, 5p, 10p, 20p, 50p, £1, £2.
• There should be a way of reloading either products or change at a later point.
• The machine should keep track of the products and change that it contains.

How to

The machine is implemented as a Grails REST application. To run it execute the following commands in a Linux terminal:

curl -s get.sdkman.io | bash
source "$HOME/.sdkman/bin/sdkman-init.sh"
sdk install grails 3.0.10
git clone https://github.com/rsilva4/vending-machine.git
cd vending-machine
grails run-app

Note: Java 7, curl, unzip and git are pre-requisites

Note 2: If you prefer and are familiar with, you can use a Docker container to isolate the environment for this purpose:

docker run --rm -it java:7 bash
apt-get update && apt-get install curl git unzip 
# execute the commands above

The machine should be used via a REST interface. All numeric prices are in pence. The following list contains the available endpoints to execute the required actions

GET /product - List products

Curl sample:

curl -X GET -H "Content-Type: application/json" 'http://localhost:8080/product'

POST /product - Add new product

Json body:

{
  "name": "A name",
  "price":120,
  "qnt": 10
}

Curl sample:

curl -X POST -H "Content-Type: application/json" -d '{   
    "denomination": "£2",
    "qnt": 10
  }' 'http://localhost:8080/change'

PUT /product/{id} - Update existing product

Json body:

{
  "name": "A name",
  "price":120,
  "qnt": 10
}

Curl sample:

curl -X PUT -H "Content-Type: application/json" -d '{   
    "qnt": 1000
  }' 'http://localhost:8080/change/1'

DELETE /product/{id} - Delete existing product

Curl sample:

curl -X DELETE -H "Content-Type: application/json" -d '{   
    "qnt": 1000
  }' 'http://localhost:8080/product/1'

GET /change - List available change

Curl sample:

curl -X GET -H "Content-Type: application/json" 'http://localhost:8080/change'

POST /change - Add new denomination

Json body:

{
  "denomination": "£2",
  "qnt": 10
}

Curl sample:

curl -X POST -H "Content-Type: application/json" -d '{   
    "denomination": "£2",
    "qnt": 10
  }' 'http://localhost:8080/change'

PUT /change/{id} - Update existing denomination

Json body:

{
  "qnt": 1000
}

Curl sample:

curl -X PUT -H "Content-Type: application/json" -d '{   
    "qnt": 1000
  }' 'http://localhost:8080/change/1'

DELETE /change/{id} - Delete existing denomination

Curl sample:

curl -X DELETE -H "Content-Type: application/json" -d '{   
    "qnt": 1000
  }' 'http://localhost:8080/change/1'

PUT /vendingMachine/buy - Buy a product

Json body:

{
    "productId":1,
    "change":["£1","2p","2p","20p","10p"]
}

Curl sample:

curl -X PUT -H "Content-Type: application/json" -d '{
    "productId":1,
    "change":["£1","2p","2p","20p","10p"]
}' 'http://localhost:8080/product/buy'

The machine initial load can be checked at Bootstrap.groovy.