The database for this application is a mongo db. You either need to have one running on your system, or you can alternatively start the MongoDB in docker with the included docker-compose file.

docker-compose -f mongodb-docker-compose up

Docker / docker-compose need to be installed for this.

The application can then be started by running the main function in:

hexagonal-example\config\src\main\java\de\strasser\peter\hexagonal\HexagonalApplication.java

What does this application do

This app can register customers, add addresses to these customers and retrieve a list of all customers.

The supported usecases in the business layer can be inspected in the applicationmodule. Under application/src/main/java/de/strasser/peter/hexagonal/application/customer/port all the supported operations are clearly visible, which is a major selling point to structure your application in this way.

Application architecture

Advantages of separated models on each layer in this example

The customer response can easily exclude the (hashed) password without much effort. This seperates the concern in what way to display the data to the client.
The customer can be persisted different from the domain models structure. The layout in this example has no benefit, but assume structuring your data in this way would give you a much needed performance boost. This way the concern on how to handle data persistence is independent from the business layer and can be handled by the persistence module.