mongo-inheritance

Spring Data MongoDB includes a _class field with each document; this is used by the object mapper to instantiate the correct model. The default repository implementation however, does not constrain queries by _class, which can lead to confusing results.

This repository implementation ensures queries only consider documents matching or inheriting from the type defined by the repository declaration, e.g. MongoRepository<Car, ObjectId>() will only consider documents with a _class field that matches or extends Car.

Usage

<dependency>
  <groupId>io.eagle</groupId>
  <artifactId>mongo-inheritance</artifactId>
  <version>1.0.11</version>
</dependency>

Include configuration to ensure all repositories are inheritance aware.

@Configuration
@EnableMongoInheritanceRepositories(basePackages={"io.eagle.mongo.models"})
public class AppConfig() {}

Rules of operation:

• All entity classes for which a repository interface is to be declared have a @Document annotation.
• All entity classes that share a common superclass are stored in the same collection.
• The shared common superclasses are usually abstract classes. They don't have to be, but usually are.
• To support inheritance, all subclasses (concrete classes) use @TypeAlias annotation to specify a specific marker used to identify class type once stored in the database.

Functionality:

• Superclass repositories should work on all data within a collection.
• Subclass repositories should only work on data that are of the subclass type - meaning that a condition involving the _class field should be automatically added to all queries before they reach MongoDB.

Inspired by https://github.com/l0co/spring-data-mongodb-inheritance-test