The Model2 System helps to work with Domain Models and Domain-driven Design (DDD) in Java. It allows to describe the various entities, their attributes, roles, and relationships, plus the constraints and concerns that govern the problem in pure Java syntax. No pre-processors or new language elements, just the standard Java platform. Everything you know from Java still applies and you can leverage both your experience and toolkits.
This work is heavily inspired by Qi4j.
The runtime system allows to plug-in concrete implementation of persistent store backend, query/index backend, locking strategies and cache provider.
Create and configure a repository:
repo = EntityRepository.newConfiguration()
.store.set( new RecordStoreAdapter( new LuceneRecordStore() ) )
.entities.set( new Class[] {Person.class} )
.create();The Person Entity class:
@Description( "Everything we know about an employee" )
public class Person extends Entity {
/** Simple property of type String, value might be null. */
@Nullable
public Property<String> name;
/** Firstname, must not be null, defaults to "Ulli" is not initialized. */
@DefaultValue("Ulli")
public Property<String> firstname;
/** Protected property of type Date. */
@Nullable
protected Property<Date> birthday;
}Create an entity of type Person in the repository:
UnitOfWork uow = repo.newUnitOfWork();
Person person = uow.createEntity( Person.class, null, (Person prototyp) -> {
prototyp.name.set( "Model2" );
return prototyp;
});
// persistently write changes to the backend store
uow.commit();Access properties of the newly created Entity:
System.out.println( "The name of the person is " + person.name.get() );