SGR Backend Implementation in Spring Boot

Quick intro to SGR

SGR is the new system for recycling PET bottles implemented in Romania, similar to other countries in the EU. It works by adding a deposit to the price of PET containers, which could be cashed out once the container is returned to one of the selected locations (usually in stores).

Libraries used

• Spring Boot
• JPA
• Hibernate

Basic configuration

It is necessary to create a configuration file (you can also use a CLI configuration if you prefere, more info available at the Spring documentation)

In the usual approach, the file is found under src/main/resources/application.properties and follows the general Spring configuration structure

For a quick start, only the following properties are necessary:

spring.application.name

spring.jpa.generate-ddl

spring.jpa.show-sql

spring.datasource.driver-class-name

spring.datasource.url

spring.datasource.username

spring.datasource.password

System architecture

Definitions

• SGRItem is a simple product that takes part in the SGR system
• SGRStore is a location that can ISSUE products or CONSUME (or SCAN) products.
• SGRPretGarantie is a price for the return issued at a certain point in time. The latest one is always valid, but the system keeps track of past ones
• SGRPurchase represents an ISSUE transaction (i.e. a product is bought from a SGRStore)

Transaction types

• ISSUE represents a purchase of an SGR item
• CONSUME (or SCAN) represents the return of a previously purchased SGR item

Workflow

Item flow:

• SGRItem gets created
• SGRStore A executes an ISSUE transaction and creates a SGRPurchase for the item
• SGRStore B executes a CONSUME transaction and the SGRPurchase is marked as SGRComplete

Note: Store A and B can be the same store, or completely different ones