Springer Nature Exercise

Springer Nature exercise newsletter webservice

Problem definition

Our application manages user subscriptions to newsletters about new book releases. Each book belongs to a set of categories and a user can subscribe to any number of those. Implement an application that provides an HTTP API for manipulating book and subscription data with the following endpoints:

with json bodies

1. POST /categories

   •  { "code": "string", "title": "string", "superCategoryCode": "string" or null }

2. POST /books

   • { "title": "string", "categoryCodes": ["code1", "code2", ...] }

3. POST /subscribers

   • { "email": "string", "categoryCodes": ["code1", "code2", ...] }

4. GET /newsletters

Endpoints

1. Endpoint should handle category submissions, a category has a unique code, a title and optionally a parent category (e.g. science -> physics)
2. Endpoint 2. should handle book submissions, a book has a title and a list of category codes of categories to which it belongs to
3. Endpoint 3. should handle subscriber submissions, a subscriber has an email and a list of category codes of categories for which he/she is interested in
4. Endpoint 4. should return a list of "newsletters", each newsletter relates to a subscriber, a newsletter has a recipient address (the subscriber's email) and a list of notifications, each notification contains the name of a book and a list of categoryPaths for it, a categoryPath is a list that shows the relation of the books' category and the category for which a subscriber is interested.

A subscriber should get notifications for books that belong to the same category or to a child category of a category in which the subscriber is interested. To make it a bit easier assume that a book can not belong to a parent and child category at the same time, for example if science is the parent category of physics then a book can not belong to both categories, only to one of them, same holds for a subscription. Also assume that the release date of a book is irrelevant and that all books are eligible for a newsletter.

Example:

Given the following category hierarchy:

• science
  • engineering
    • software
      • functional_programming
      • object_oriented_programming

If a subscriber is interested in engineering and a book e.g. " Programming in Scala " belongs to the category functional_programming , then one of the categoryPaths for that book in that subscriber's email notification is:

    ["engineering", "software", "functional_programming"]

if the same book also belongs to the category object_oriented_programming then that same book has also a categoryPath :

    ["engineering", "software", "object_oriented_programming"]

and the /newsletters response body should be:

[
    {
        "recipient": "[email protected]",
        "notifications": [
            {
                "book": "Programming in Scala",
                "categoryPaths": [
                    ["engineering", "software", "functional_programming"],
                    ["engineering", "software", "object_oriented_programming"]
                ]
            }
        ]
    }
]

Project setup

Import the Maven project file (pom.xml) into your IDE. The project use the Spring framework. The Spring tools helps your development.

Project execution

Choose one possible way to start the newsletter web service

• IDE
  • Run the project (com.springernature.newsletter.NewsletterApplication) class as a Spring Boot Application
• Build/ JAR File (installed maven required)
  • open the command line at project root
  • mvnw clean package
  • java -jar target/newsletter-0.1.0.jar
• Maven run (installed maven required)
  • open the command line at project root
  • mvnw spring-boot:run

Open the URL http://localhost:8080 in your browser and test the web service as described above