final DBCollection shapes = getDb().getCollection("shapes");
final DBCollection shapeshifters = getDb().getCollection("shapeshifters");
getMorphia().map(Circle.class).map(Rectangle.class).map(ShapeShifter.class);
final Shape rectangle = new Rectangle(2, 5);
final DBObject rectangleDbObj = getMorphia().toDBObject(rectangle);
shapes.save(rectangleDbObj);
final BasicDBObject rectangleDbObjLoaded = (BasicDBObject) shapes.findOne(new BasicDBObject(Mapper.ID_KEY,
rectangleDbObj.get(Mapper.ID_KEY)));
final Shape rectangleLoaded = getMorphia().fromDBObject(Shape.class, rectangleDbObjLoaded, new DefaultEntityCache());
assertTrue(rectangle.getArea() == rectangleLoaded.getArea());
assertTrue(rectangleLoaded instanceof Rectangle);
final ShapeShifter shifter = new ShapeShifter();
shifter.setReferencedShape(rectangleLoaded);
shifter.setMainShape(new Circle(2.2));