Question

Given that, in Objectify, an entity group is not defined by a class, but by an instance, and that you can create child entites with a parent Key that points to a nonexistant entity, how would you do that? (I’m looking for a simple example. The statements above are from Objectify documentation, and I’m confused.)

Answer 1

Just create a Key with an arbitrary id. A simple example:

class Foo {
    @Parent Key<Par> parent;
    @Id Long id;
    // ...constructors, etc
}

// Create a parent key for which an entity may or may not exist, doesn't matter
Key<Par> parent = Key.create(Par.class, 123L);

Foo foo = new Foo(parent, someId);
ofy().save().entity(foo).now();