Video Rental Store

Architecture

The application architecture is based on three well established architectural design patterns: Ports & Adapters (aka Hexagonal Architecture), CQRS and Event Sourcing. I've splitted the application core into three bounded contexts: Users, Movie catalog and Rentals, each one packed as module.

The application core of each module is composed by an application layer, a domain layer and persistence layer. There's also a fourth module that implements an adapter for the application that consists on a RESTful API.

Code Structure

The project contains a parent project video-rental-storethat groups 4 modules:

• video-rental-store-catalog - The module responsible to manage the collection of videos available for renting.

• video-rental-store-user - The module responsible to manage users of the video-rental-store.

• video-rental-store-rentals - The module responsible to create rentals and then add movies and return them.

• video-rental-store-restapi - An implementation of RESTful API that groups the features provided by Users, Movies and Rentals modules.

The modules that represent each bounded context follow this packaging structure:

• com.casumo.videorentalstore.XXX.core.application - Orchestration of the use cases than be triggered on the application.
• com.casumo.videorentalstore.XXX.core.domain - Logic and data to support the business rules.
• com.casumo.videorentalstore.XXX.core.persistence - Represents the interfaces (Repositories) required for storing data by the application core.
• com.casumo.videorentalstore.XXX.core.port - Represents the interface for the features provided by the application core.

Implementation details

I've made use of the following frameworks in order to ease the developments:

• Spring Boot - For REST and HATEOAS support, beyond others features provided by spring framework.
• Axon - For event sourcing and CQRS support.
• Springfox - For API documentation

Throughout the application life, data is stored on an in-memory database. There two models persisted, one for writes, implemented as aggregates, following the concepts of DDD and stored as a set of events, and another model, for reads, following a conventional relational model.

The interaction with the domain model of each bonded context is done by publishing commands on a internal bus.

Requirements

For building and running the application you need:

• JDK 1.8
• Maven 3

Build

mvn clean install

Running the application locally

There are several ways to run a Spring Boot application on your local machine. One way is to execute the main method in the com.casumo.videorentalstore.App class from your IDE.

Alternatively you can use the Spring Boot Maven plugin like so:

cd restapi && mvn spring-boot:run

You can then access to the URL http://localhost:8080/api/swagger-ui.html#/

ToDo / Next steps

• Implement authorization schema on the API
• Implement delete operations for all resources.
• Split the monolithic application into a set of microservices (one for each bounded context)
• Improve code coverage of unit/integration tests
• Improve API documentation