Hibernate search - multi field sort - hibernate-search

Question

I am using hibernate search to search nearby stores. Each store belongs to supermarket.
We used to fetch all nearby stores by using hibernate search.
Search results:
Supermaket 1 - Shop 1 (0.5 km)
Supermaket 2 - Shop 1 (1 km)
Supermaket 2 - Shop 2 (1.1 km)
Supermaket 1 - Shop 2 (2 km)
But recent requirement came where we need to group the search by Supermarkets and show that on the app.
Supermaket 1
Shop 1 (0.5 km)
Shop 2 (2 km)
Supermaket 2
Shop 1 (1 km)
Shop 2 (1.1 km)
#Indexed
#Entity
class Shop {
#Id
#Column(name = "Id")
#GeneratedValue(strategy = GenerationType.AUTO)
private int id;
#ManyToOne
#JoinColumn(name = "SuperMarketId")
#IndexedEmbedded
private SuperMarket superMarket;
#Column(name = "Latitude")
#Latitude(of = "location")
private double latitude;
#Column(name = "Longitude")
#Longitude(of = "location")
private double longitude;
}
#Indexed
#Entity
class SuperMarket {
#Id
#Column(name = "Id")
#GeneratedValue(strategy = GenerationType.AUTO)
private int id;
}
I was using sort field:
Sort sort = new Sort(
new DistanceSortField(lat, lng, "location"));
query.setSort(sort);
I have to sort by distance and shops how do I do it.
I tried:
Sort sort = new Sort(
new DistanceSortField(lat, lng, "location"),
new SortField("superMarket.id", SortField.Type.STRING, true));
query.setSort(sort);
Bascially looking for solution in hibernate search where we could order by distance, id. - 2 fields

Answer 1

As an alternative, you may be interested in faceting, which tries to address the same problem, but is not affected by the problem of ordering.
If you really want grouping... you seem to be aware of that, but you will need to perform some post-processing on your data.
Something like:
List<Shop> shops = fullTextQuery.getResultList();
Map<Supermarket, List<Shop>> results =
shops.stream().collect( Collectors.groupingBy( Shop::getSupermarket, LinkedHashMap::new, Collectors.toList() ) ;
Now about the order... It depends what you want. Assuming your results are paginated, if a shop of supermarket 1 was previously on page 2, do you want it to appear on page 1 regardless of its distance? I.e. do you want to sort first by supermarket, then by distance? If so, just do this:
Sort sort = new Sort(
new SortField("superMarket.id", SortField.Type.STRING, true),
new DistanceSortField(lat, lng, "location")
);
query.setSort(sort);
Or do you want it to stay on page two, and have potentially the same supermarket appear on multiple pages? If so, use the same sort you gave in your question:
Sort sort = new Sort(
new DistanceSortField(lat, lng, "location"),
new SortField("superMarket.id", SortField.Type.STRING, true));
query.setSort(sort);

Answer 2

I finally figured it out from "https://developer.jboss.org/thread/267686":
You need to add Fields and SortableField annotation to Id of supermarket:
#Indexed
#Entity
class SuperMarket {
#Id
#Column(name = "Id")
#GeneratedValue(strategy = GenerationType.AUTO)
#Fields({
#Field(name = "id_sort", analyze = Analyze.NO, store = Store.NO, index = Index.NO) })
#SortableField(forField = "id_sort")
private int id;
}
Sort sort = new Sort(
new DistanceSortField(lat, lng, "location"),
new SortField("superMarket.id_sort", SortField.Type.INT, true));
query.setSort(sort);
The sort field was getting ignored previously.