Hibernate Search - Mapping a property to the document identifier explicitly with @DocumentId

Hibernate Search Explicit identifier mapping

Explicit identifier mapping is required in the following cases:

The document identifier is not the entity identifier.

OR the entity identifier has a type that is not supported by default. This is the case of composite identifiers, in particular.

To select a property to map to the document identifier, just apply the @DocumentId annotation to that property:

Mapping a property to the document identifier explicitly with @DocumentId
@Entity
@Indexed
public class Book {

    @Id
    @GeneratedValue
    private Integer id;

    @NaturalId
    @DocumentId
    private String isbn;

    public Book() {
    }

    // Getters and setters
    // ...

}
When the property type is not supported, it is also necessary to implement a custom identifier bridge, then refer to it in the @DocumentId annotation:

Mapping a property with unsupported type to the document identifier with @DocumentId
@Entity
@Indexed
public class Book {

    @Id
    @Convert(converter = ISBNAttributeConverter.class)
    @DocumentId(identifierBridge = @IdentifierBridgeRef(type = ISBNIdentifierBridge.class))
    private ISBN isbn;

    public Book() {
    }

    // Getters and setters
    // ...

}