Offer service

Dear stargazers, hope you like the project. Feel free to ask questions. I'll add some diagrams when I get a chance

This is a REST based service that allows API consumers to create, cancel and query offers for merchants.

The project was developed using TDD. The system architecture is heavily inspired by Robert C. Martin's Clean Architecture, a use case driven approach. I developed this program with the mindset that this module is apart of a large system and attempted to make it as modular and pluggable as possible.

The APIs invoke a single Use Case. The Use Case constructs and acts over one to many Entities and in doing so also talks to a Gateway more commonly known as Repository or Adapters. When an API needs to return a result, a Presenter is passed into the API. As we pass through the various layers we use separate models. Use Cases produce Response Models, Presenters produce View Models.

For the delivery mechanism I used Spring's REST controllers to deliver JSON

There are 4 public APIs

• Create Offer

POST /offer-service/api/v1/offers
{
  "name: "offer name",
  "description: "offer description",
  "price: "5.00",
  "currency: "GBP",
  "duration: {
    "startDate: "2018-01-01",
    "endDate: "2018-01-31"
  }
}

Response
HTTP Status 201 Created
{
  id: "12c3009d-046d-411c-85eb-6e379e2f5d2a"
}

• Cancel Offer

There are various ways in which we could cancel an offer e.g. use the PATCH or DELETE HTTP method, I instead opted for a command style

POST /offer-service/api/v1/offers/{offer-id}/cancel

Response
HTTP Status 204 No Content

• Get Offers

GET  /offer-service/api/v1/offers`

Response
HTTP Status 200
offers: [
  {
    id: "12c3009d-046d-411c-85eb-6e379e2f5d2a",
    name: "offer name",
    description: "offer description",
    price: "5.00",
    currency: "GBP",
    duration: {
      startDate: "2018-01-01",
      endDate: "2018-01-31"
    },
    status: "ACTIVE|EXPIRED"
  },
  {
    id: "cc3453d7-6d75-422c-87da-37ee9f65bd11",
    ...
  },
  {
    id: "3f5f779c-b145-49fd-8a73-c8770fad072a",
    ...
  }
]

• Get Offer by ID

GET  /offer-service/api/v1/offers/{offer-id}`

Response
HTTP Status 200
{
  id: "12c3009d-046d-411c-85eb-6e379e2f5d2a",
  name: "offer name",
  description: "offer description",
  price: "5.00",
  currency: "GBP",
  duration: {
    startDate: "2018-01-01",
    endDate: "2018-01-31"
  },
  status: "ACTIVE|EXPIRED"
}

Or

HTTP Status 404 Not Found

Project dependencies

This project uses Java 8 with Spring Boot, H2 database and Swagger for API documentation. Tests were written with JUnit4.

Running the application

To build the project, run:

gradlew clean build

To run the application, from the root of the project run:

gradlew bootRun

View the Swagger documentation