DATAMONGO-2044 make ensureNotIterable actually check if object is iterable

[GotoFinal]

Other option would be just to remove that check, as it might be possible that someone is saving objects that implement iterable but are valid data classes?

As current code just does nothing, as object can be of type that is implementing one of that interfaces, but it can not be of interface type itself.

[GotoFinal]

Now I'm confused as now I see there is a test that ensures that iterable item will pass here, so maybe this code should be just removed?

spring-data-mongodb/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/mapping/MappingTests.java

Lines 497 to 518 in 9843325

	@Test // DATAMONGO-805
	public void shouldMapFieldsOfIterableEntity() {
	template.dropCollection(IterableItem.class);
	template.dropCollection(Container.class);
	Item item = new IterableItem();
	item.value = "bar";
	template.insert(item);
	Container container = new Container("foo");
	container.item = item;
	template.insert(container);
	Query query = new Query(Criteria.where("id").is("foo"));
	Container result = template.findOne(query, Container.class);
	assertThat(result, is(notNullValue()));
	assertThat(result.item, is(notNullValue()));
	assertThat(result.item.value, is("bar"));
	}

But issues itself is not about iterable entities: https://jira.spring.io/browse/DATAMONGO-805

Other option would be to check if it is an array or collection - but then someone can implement collection in same way (as simple delegated wrapper) as in test mentioned above and that would be still valid data class? But I will change this commit to use collection for now and wait for some feedback.

[christophstrobl]

thanks @GotoFinal. Sorry it took so long - merged to main line.