Get an Objectify Entity's Key

Question

Dummy question.

I create my POJO Objectify entity (for example, \"Category\") and persist it.

Then I retrieve it via a query.

I want to use it in a

Answer 1

The Key class in Objectify 4 has this method:

public static <T> Key<T> create(T pojo)

so, if you already have read the entity (called category in this example) from the datastore, you can just call

product.categoria = Key.create(category);

Answer 2

For objectify 4 use:

public Key<Foo> getKey() {
   return Key.create(Foo.class, id);
}

Or if the entity has a @Parent

public Key<Bar> getKey() {
   return Key.create(parentKey, Bar.class, id);
}

Answer 3

I'm usually adding an extra method:

@Transient
Key<Categoria> getKey() {
   return Key.create(Categoria.class, id);
}

and use it where it needed:

anCategoria.getKey()