gistfile1.txt

@Test
  public void foo() {

		TypeBasedAggregationOperationContext context = new TypeBasedAggregationOperationContext(Foo.class,
				new MongoMappingContext(), new QueryMapper(converter));

		Aggregation aggregation = newAggregation(Foo.class, group("bar.name"));
		aggregation.toDbObject("foo", context);
	}

	static class Foo {

		Bar bar;
	}

	static class Bar {

		String name;
	}