Elasticsearch Repositories

This chapter includes details of the Elasticsearch repository implementation.

Example 1. The sample Book entity

@Document(indexName="books")
class Book {
    @Id
    private String id;

    @Field(type = FieldType.text)
    private String name;

    @Field(type = FieldType.text)
    private String summary;

    @Field(type = FieldType.Integer)
    private Integer price;

	// getter/setter ...
}

Automatic creation of indices with the corresponding mapping

The @Document annotation has an argument createIndex. If this argument is set to true - which is the default value - Spring Data Elasticsearch will during bootstrapping the repository support on application startup check if the index defined by the @Document annotation exists.

If it does not exist, the index will be created and the mappings derived from the entity’s annotations (see Elasticsearch Object Mapping) will be written to the newly created index. Details of the index that will be created can be set by using the @Setting annotation, refer to Index settings for further information.

Annotations for repository methods

@Highlight

The @Highlight annotation on a repository method defines for which fields of the returned entity highlighting should be included.To search for some text in a Book 's name or summary and have the found data highlighted, the following repository method can be used:

interface BookRepository extends Repository<Book, String> {

    @Highlight(fields = {
        @HighlightField(name = "name"),
        @HighlightField(name = "summary")
    })
    SearchHits<Book> findByNameOrSummary(String text, String summary);
}

It is possible to define multiple fields to be highlighted like above, and both the @Highlight and the @HighlightField annotation can further be customized with a @HighlightParameters annotation. Check the Javadocs for the possible configuration options.

In the search results the highlight data can be retrieved from the SearchHit class.

@SourceFilters

Sometimes the user does not need to have all the properties of an entity returned from a search but only a subset. Elasticsearch provides source filtering to reduce the amount of data that is transferred across the network to the application.

When working with Query implementations and the ElasticsearchOperations this is easily possible by setting a source filter on the query.

When using repository methods there is the @SourceFilters annotation:

interface BookRepository extends Repository<Book, String> {

    @SourceFilters(includes = "name")
    SearchHits<Book> findByName(String text);
}

In this example, all the properties of the returned Book objects would be null except the name.

Annotation based configuration

The Spring Data Elasticsearch repositories support can be activated using an annotation through JavaConfig.

Example 2. Spring Data Elasticsearch repositories using JavaConfig

@Configuration
@EnableElasticsearchRepositories(                             (1)
  basePackages = "org.springframework.data.elasticsearch.repositories"
  )
static class Config {

  @Bean
  public ElasticsearchOperations elasticsearchTemplate() {    (2)
      // ...
  }
}

class ProductService {

  private ProductRepository repository;                       (3)

  public ProductService(ProductRepository repository) {
    this.repository = repository;
  }

  public Page<Product> findAvailableBookByName(String name, Pageable pageable) {
    return repository.findByAvailableTrueAndNameStartingWith(name, pageable);
  }
}

1	The `EnableElasticsearchRepositories` annotation activates the Repository support. If no base package is configured, it will use the one of the configuration class it is put on.
2	Provide a Bean named `elasticsearchTemplate` of type `ElasticsearchOperations` by using one of the configurations shown in the Elasticsearch Operations chapter.
3	Let Spring inject the Repository bean into your class.

Spring Namespace

The Spring Data Elasticsearch module contains a custom namespace allowing definition of repository beans as well as elements for instantiating a ElasticsearchServer .

Using the repositories element looks up Spring Data repositories as described in Creating Repository Instances.

Example 3. Setting up Elasticsearch repositories using Namespace

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:elasticsearch="http://www.springframework.org/schema/data/elasticsearch"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       https://www.springframework.org/schema/beans/spring-beans-3.1.xsd
       http://www.springframework.org/schema/data/elasticsearch
       https://www.springframework.org/schema/data/elasticsearch/spring-elasticsearch-1.0.xsd">

  <elasticsearch:repositories base-package="com.acme.repositories" />

</beans>

Using the Transport Client or Rest Client element registers an instance of Elasticsearch Server in the context.

Example 4. Transport Client using Namespace

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:elasticsearch="http://www.springframework.org/schema/data/elasticsearch"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       https://www.springframework.org/schema/beans/spring-beans-3.1.xsd
       http://www.springframework.org/schema/data/elasticsearch
       https://www.springframework.org/schema/data/elasticsearch/spring-elasticsearch-1.0.xsd">

  <elasticsearch:transport-client id="client" cluster-nodes="localhost:9300,someip:9300" />

</beans>

Example 5. Rest Client using Namespace

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:elasticsearch="http://www.springframework.org/schema/data/elasticsearch"
       xsi:schemaLocation="http://www.springframework.org/schema/data/elasticsearch
       https://www.springframework.org/schema/data/elasticsearch/spring-elasticsearch.xsd
       http://www.springframework.org/schema/beans
       https://www.springframework.org/schema/beans/spring-beans.xsd">

  <elasticsearch:rest-client id="restClient" hosts="http://localhost:9200">

</beans>