Missing hashCode and equals methods in JoinField

[xhaggi]

The class JoinField is missing the hashCode and equals methods.

[sothawo]

backported to 4.2.x and 4.1.x

[xhaggi]

Thank you 👍

[tuomoa]

@sothawo is there a reason that not all the classes implement equals (and hashCode)? I think all the classes under org.springframework.data.elasticsearch.core.query do not implement these. This makes it harder to compare queries for example in unit tests with argument matches and equality assertions.

[sothawo]

What would equals mean for queries?

A NativeQuery for example contains original Elasticsearch classes like co.elastic.clients.elasticsearch.core.search.Suggester which do not offer equality information, so a NativeQuery would have to use object identity.

Should these queries be the same:

		Query query1 = CriteriaQuery.builder(
						new Criteria("firstName").is("James").and("lastName").is("Bond"))
				.build();
		Query query2 = CriteriaQuery.builder(
						new Criteria("lastName").is("Bond").and("firstName").is("James"))
				.build();

And should a CriteriaQuery and a StringQuery that in the end produce the same query that is sent to Elasticsearch be equal?

It might make sense to have equals/hashcode for some classes, feel free to create an issue for that an provide a PR.

[tuomoa]

Hmm yeah it might not be feasible to handle equality in all cases. I suppose that the example case might be interpreted as not equal and that's all right but it might be nice to be able to compare simple case such as CriteriaQuery.builder(new Criteria("firstName").is("James").and("lastName").is("Bond")).build()with CriteriaQuery.builder(new Criteria("firstName").is("James").and("lastName").is("Bond")).build() and see that they are equal. But all right 👍