How to index field as suggest type?

Question

I want to use the suggest feature of elastic-search for autocomplete. https://www.elastic.co/guide/en/elasticsearch/reference/current/search-suggesters.html it is perfectly fit for my requirements, but I cannot find a way to create an index for this field. There is FieldType enum type for search-index types, but it does not contain suggest type, and I don't see any way to extend it. nothing is in the documentation about this. Is it even possible to index some elastic specific field by hibernate-search?

Answer 1

To elaborate on my comment: no, this is not possible in Hibernate Search 5, but...

You can implement autocomplete yourself.

Define an analyzer with an edge-ngram token filer for indexing, and another for querying, as explained here.

Then use these analyzers on the field you want to add autocomplete to:

@Field(name = "myField_autocomplete", analyzer = @Analyzer(definition = "edgeNGram"))
@Field(name = "dummy", analyzer = @Analyzer(definition = "edgeNGram_query")
String myField;

Note the "dummy" field is required because of some limitations in Hibernate Search 5, in order to make sure the "edgeNGram_query" analyzer is available in your index. See here for details about this hack.

Then reindex your data.

Then you will query this way:

String userInput = ...;
QueryBuilder builder = fullTextEntityManager.getSearchFactory().buildQueryBuilder()
        .forEntity(Contact.class)
        .overridesForField("myField", "edgeNGram_query")
        .get();

Query luceneQuery = builder.keyword().onField("myField").matching(userInput).createQuery();

FullTextQuery query = fullTextEntityManager.createQuery( luceneQuery, MyEntity.class );

List<MyEntity> results = query.getResultList();

Note that these limitations (not being able to use the suggest type, having to hack around to define a query-only analyzer) will be gone in Hibernate Search 6, which is still in development.