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Table of Contents

Preface

The Spring Data Solr project applies core Spring concepts to the development of solutions using the Apache Solr Search Engine. We provide a "template" as a high-level abstraction for storing and querying documents. You will notice similarities to the mongodb support in the Spring Framework.

Project Metadata

Requirements

Requires Apache Solr 5. Preferably the latest 5.x version.

<dependency>
  <groupId>org.apache.solr</groupId>
  <artifactId>solr-core</artifactId>
  <version>${solr.version}</version>
</dependency>

1. New & Noteworthy

1.1. What’s new in Spring Data for Apache Solr 2.1

  • Autoselect Solr core using SolrTemplate.

  • Assert upwards compatibility with Apache Solr 6 (incl. 6.3).

  • Support for combined Facet and Highlight Query.

  • Allow reading single valued multivalue fields into non collection property.

  • Use native SolrJ schema api.

1.2. What’s new in Spring Data for Apache Solr 2.0

  • Upgrade to Apache Solr 5.

  • Support RequestMethod when querying.

1.3. What’s new in Spring Data for Apache Solr 1.5

1.4. What’s new in Spring Data for Apache Solr 1.4

  • Upgraded to recent Solr 4.10.x distribution (requires Java 7).

  • Add support for Realtime Get.

  • Get Field Stats (max, min, sum, count, mean, missing, stddev and distinct calculations).

  • Use @Score to automatically add projection on document score (See: Special Fields).

2. Working with Spring Data Repositories

The goal of the Spring Data repository abstraction is to significantly reduce the amount of boilerplate code required to implement data access layers for various persistence stores.

Spring Data repository documentation and your module

This chapter explains the core concepts and interfaces of Spring Data repositories. The information in this chapter is pulled from the Spring Data Commons module. It uses the configuration and code samples for the Java Persistence API (JPA) module. You should adapt the XML namespace declaration and the types to be extended to the equivalents of the particular module that you use. “Namespace reference” covers XML configuration, which is supported across all Spring Data modules supporting the repository API. “Repository query keywords” covers the query method keywords supported by the repository abstraction in general. For detailed information on the specific features of your module, see the chapter on that module of this document.

2.1. Core concepts

The central interface in the Spring Data repository abstraction is Repository. It takes the domain class to manage as well as the ID type of the domain class as type arguments. This interface acts primarily as a marker interface to capture the types to work with and to help you to discover interfaces that extend this one. The CrudRepository provides sophisticated CRUD functionality for the entity class that is being managed.

Example 1. CrudRepository interface
public interface CrudRepository<T, ID extends Serializable>
    extends Repository<T, ID> {

    <S extends T> S save(S entity); (1)

    T findOne(ID primaryKey);       (2)

    Iterable<T> findAll();          (3)

    Long count();                   (4)

    void delete(T entity);          (5)

    boolean exists(ID primaryKey);  (6)

    // … more functionality omitted.
}
1 Saves the given entity.
2 Returns the entity identified by the given ID.
3 Returns all entities.
4 Returns the number of entities.
5 Deletes the given entity.
6 Indicates whether an entity with the given ID exists.
We also provide persistence technology-specific abstractions, such as JpaRepository or MongoRepository. Those interfaces extend CrudRepository and expose the capabilities of the underlying persistence technology in addition to the rather generic persistence technology-agnostic interfaces such as CrudRepository.

On top of the CrudRepository, there is a PagingAndSortingRepository abstraction that adds additional methods to ease paginated access to entities:

Example 2. PagingAndSortingRepository interface
public interface PagingAndSortingRepository<T, ID extends Serializable>
  extends CrudRepository<T, ID> {

  Iterable<T> findAll(Sort sort);

  Page<T> findAll(Pageable pageable);
}

To access the second page of User by a page size of 20, you could do something like the following:

PagingAndSortingRepository<User, Long> repository = // … get access to a bean
Page<User> users = repository.findAll(new PageRequest(1, 20));

In addition to query methods, query derivation for both count and delete queries is available. The following list shows the interface definition for a derived count query:

Example 3. Derived Count Query
public interface UserRepository extends CrudRepository<User, Long> {

  Long countByLastname(String lastname);
}

The following list shows the interface definition for a derived delete query:

Example 4. Derived Delete Query
public interface UserRepository extends CrudRepository<User, Long> {

  Long deleteByLastname(String lastname);

  List<User> removeByLastname(String lastname);

}

2.2. Query methods

Standard CRUD functionality repositories usually have queries on the underlying datastore. With Spring Data, declaring those queries becomes a four-step process:

  1. Declare an interface extending Repository or one of its subinterfaces and type it to the domain class and ID type that it should handle, as shown in the following example:

    interface PersonRepository extends Repository<Person, Long> { … }
  2. Declare query methods on the interface.

    interface PersonRepository extends Repository<Person, Long> {
      List<Person> findByLastname(String lastname);
    }
  3. Set up Spring to create proxy instances for those interfaces, either with JavaConfig or with XML configuration.

    1. To use Java configuration, create a class similar to the following:

      import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
      
      @EnableJpaRepositories
      class Config {}
    2. To use XML configuration, define a bean similar to the following:

      <?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:jpa="http://www.springframework.org/schema/data/jpa"
         xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans.xsd
           http://www.springframework.org/schema/data/jpa
           http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">
      
         <jpa:repositories base-package="com.acme.repositories"/>
      
      </beans>

    The JPA namespace is used in this example. If you use the repository abstraction for any other store, you need to change this to the appropriate namespace declaration of your store module. In other words, you should exchange jpa in favor of, for example, mongodb.

    + Also, note that the JavaConfig variant does not configure a package explicitly, because the package of the annotated class is used by default. To customize the package to scan, use one of the basePackage… attributes of the data-store-specific repository’s @Enable${store}Repositories-annotation.

  4. Inject the repository instance and use it, as shown in the following example:

    public class SomeClient {
    
      @Autowired
      private PersonRepository repository;
    
      public void doSomething() {
        List<Person> persons = repository.findByLastname("Matthews");
      }
    }

The sections that follow explain each step in detail:

2.3. Defining Repository Interfaces

First, define a domain class-specific repository interface. The interface must extend Repository and be typed to the domain class and an ID type. If you want to expose CRUD methods for that domain type, extend CrudRepository instead of Repository.

2.3.1. Fine-tuning Repository Definition

Typically, your repository interface extends Repository, CrudRepository, or PagingAndSortingRepository. Alternatively, if you do not want to extend Spring Data interfaces, you can also annotate your repository interface with @RepositoryDefinition. Extending CrudRepository exposes a complete set of methods to manipulate your entities. If you prefer to be selective about the methods being exposed, copy the methods you want to expose from CrudRepository into your domain repository.

Doing so lets you define your own abstractions on top of the provided Spring Data Repositories functionality.

The following example shows how to selectively expose CRUD methods (findById and save, in this case):

Example 5. Selectively exposing CRUD methods
@NoRepositoryBean
interface MyBaseRepository<T, ID extends Serializable> extends Repository<T, ID> {

  T findOne(ID id);

  T save(T entity);
}

interface UserRepository extends MyBaseRepository<User, Long> {
  User findByEmailAddress(EmailAddress emailAddress);
}

In the prior example, you defined a common base interface for all your domain repositories and exposed findOne(…) as well as save(…).These methods are routed into the base repository implementation of the store of your choice provided by Spring Data (for example, if you use JPA, the implementation is SimpleJpaRepository), because they match the method signatures in CrudRepository. So the UserRepository can now save users, find individual users by ID, and trigger a query to find Users by email address.

The intermediate repository interface is annotated with @NoRepositoryBean. Make sure you add that annotation to all repository interfaces for which Spring Data should not create instances at runtime.

2.3.2. Using Repositories with Multiple Spring Data Modules

Using a unique Spring Data module in your application makes things simple, because all repository interfaces in the defined scope are bound to the Spring Data module. Sometimes, applications require using more than one Spring Data module. In such cases, a repository definition must distinguish between persistence technologies. When it detects multiple repository factories on the class path, Spring Data enters strict repository configuration mode. Strict configuration uses details on the repository or the domain class to decide about Spring Data module binding for a repository definition:

  1. If the repository definition extends the module-specific repository, then it is a valid candidate for the particular Spring Data module.

  2. If the domain class is annotated with the module-specific type annotation, then it is a valid candidate for the particular Spring Data module. Spring Data modules accept either third-party annotations (such as JPA’s @Entity) or provide their own annotations (such as @Document for Spring Data MongoDB and Spring Data Elasticsearch).

The following example shows a repository that uses module-specific interfaces (JPA in this case):

Example 6. Repository definitions using module-specific interfaces
interface MyRepository extends JpaRepository<User, Long> { }

@NoRepositoryBean
interface MyBaseRepository<T, ID extends Serializable> extends JpaRepository<T, ID> {
  …
}

interface UserRepository extends MyBaseRepository<User, Long> {
  …
}

MyRepository and UserRepository extend JpaRepository in their type hierarchy. They are valid candidates for the Spring Data JPA module.

The following example shows a repository that uses generic interfaces:

Example 7. Repository definitions using generic interfaces
interface AmbiguousRepository extends Repository<User, Long> {
 …
}

@NoRepositoryBean
interface MyBaseRepository<T, ID extends Serializable> extends CrudRepository<T, ID> {
  …
}

interface AmbiguousUserRepository extends MyBaseRepository<User, Long> {
  …
}

AmbiguousRepository and AmbiguousUserRepository extend only Repository and CrudRepository in their type hierarchy. While this is perfectly fine when using a unique Spring Data module, multiple modules cannot distinguish to which particular Spring Data these repositories should be bound.

The following example shows a repository that uses domain classes with annotations:

Example 8. Repository definitions using domain classes with annotations
interface PersonRepository extends Repository<Person, Long> {
 …
}

@Entity
public class Person {
  …
}

interface UserRepository extends Repository<User, Long> {
 …
}

@Document
public class User {
  …
}

PersonRepository references Person, which is annotated with the JPA @Entity annotation, so this repository clearly belongs to Spring Data JPA. UserRepository references User, which is annotated with Spring Data MongoDB’s @Document annotation.

The following bad example shows a repository that uses domain classes with mixed annotations:

Example 9. Repository definitions using domain classes with mixed annotations
interface JpaPersonRepository extends Repository<Person, Long> {
 …
}

interface MongoDBPersonRepository extends Repository<Person, Long> {
 …
}

@Entity
@Document
public class Person {
  …
}

This example shows a domain class using both JPA and Spring Data MongoDB annotations. It defines two repositories, JpaPersonRepository and MongoDBPersonRepository. One is intended for JPA and the other for MongoDB usage. Spring Data is no longer able to tell the repositories apart, which leads to undefined behavior.

Repository type details and distinguishing domain class annotations are used for strict repository configuration to identify repository candidates for a particular Spring Data module. Using multiple persistence technology-specific annotations on the same domain type is possible and enables reuse of domain types across multiple persistence technologies. However, Spring Data can then no longer determine a unique module with which to bind the repository.

The last way to distinguish repositories is by scoping repository base packages. Base packages define the starting points for scanning for repository interface definitions, which implies having repository definitions located in the appropriate packages. By default, annotation-driven configuration uses the package of the configuration class. The base package in XML-based configuration is mandatory.

The following example shows annotation-driven configuration of base packages:

Example 10. Annotation-driven configuration of base packages
@EnableJpaRepositories(basePackages = "com.acme.repositories.jpa")
@EnableMongoRepositories(basePackages = "com.acme.repositories.mongo")
interface Configuration { }

2.4. Defining Query Methods

The repository proxy has two ways to derive a store-specific query from the method name:

  • By deriving the query from the method name directly.

  • By using a manually defined query.

Available options depend on the actual store. However, there must be a strategy that decides what actual query is created. The next section describes the available options.

2.4.1. Query Lookup Strategies

The following strategies are available for the repository infrastructure to resolve the query. With XML configuration, you can configure the strategy at the namespace through the query-lookup-strategy attribute. For Java configuration, you can use the queryLookupStrategy attribute of the Enable${store}Repositories annotation. Some strategies may not be supported for particular datastores.

  • CREATE attempts to construct a store-specific query from the query method name. The general approach is to remove a given set of well known prefixes from the method name and parse the rest of the method. You can read more about query construction in “Query Creation”.

  • USE_DECLARED_QUERY tries to find a declared query and throws an exception if cannot find one. The query can be defined by an annotation somewhere or declared by other means. Consult the documentation of the specific store to find available options for that store. If the repository infrastructure does not find a declared query for the method at bootstrap time, it fails.

  • CREATE_IF_NOT_FOUND (default) combines CREATE and USE_DECLARED_QUERY. It looks up a declared query first, and, if no declared query is found, it creates a custom method name-based query. This is the default lookup strategy and, thus, is used if you do not configure anything explicitly. It allows quick query definition by method names but also custom-tuning of these queries by introducing declared queries as needed.

2.4.2. Query Creation

The query builder mechanism built into Spring Data repository infrastructure is useful for building constraining queries over entities of the repository. The mechanism strips the prefixes find…By, read…By, query…By, count…By, and get…By from the method and starts parsing the rest of it. The introducing clause can contain further expressions, such as a Distinct to set a distinct flag on the query to be created. However, the first By acts as delimiter to indicate the start of the actual criteria. At a very basic level, you can define conditions on entity properties and concatenate them with And and Or. The following example shows how to create a number of queries:

Example 11. Query creation from method names
public interface PersonRepository extends Repository<User, Long> {

  List<Person> findByEmailAddressAndLastname(EmailAddress emailAddress, String lastname);

  // Enables the distinct flag for the query
  List<Person> findDistinctPeopleByLastnameOrFirstname(String lastname, String firstname);
  List<Person> findPeopleDistinctByLastnameOrFirstname(String lastname, String firstname);

  // Enabling ignoring case for an individual property
  List<Person> findByLastnameIgnoreCase(String lastname);
  // Enabling ignoring case for all suitable properties
  List<Person> findByLastnameAndFirstnameAllIgnoreCase(String lastname, String firstname);

  // Enabling static ORDER BY for a query
  List<Person> findByLastnameOrderByFirstnameAsc(String lastname);
  List<Person> findByLastnameOrderByFirstnameDesc(String lastname);
}

The actual result of parsing the method depends on the persistence store for which you create the query. However, there are some general things to notice:

  • The expressions are usually property traversals combined with operators that can be concatenated. You can combine property expressions with AND and OR. You also get support for operators such as Between, LessThan, GreaterThan, and Like for the property expressions. The supported operators can vary by datastore, so consult the appropriate part of your reference documentation.

  • The method parser supports setting an IgnoreCase flag for individual properties (for example, findByLastnameIgnoreCase(…)) or for all properties of a type that supports ignoring case (usually String instances — for example, findByLastnameAndFirstnameAllIgnoreCase(…)). Whether ignoring cases is supported may vary by store, so consult the relevant sections in the reference documentation for the store-specific query method.

  • You can apply static ordering by appending an OrderBy clause to the query method that references a property and by providing a sorting direction (Asc or Desc). To create a query method that supports dynamic sorting, see “Special parameter handling”.

2.4.3. Property Expressions

Property expressions can refer only to a direct property of the managed entity, as shown in the preceding example. At query creation time, you already make sure that the parsed property is a property of the managed domain class. However, you can also define constraints by traversing nested properties. Consider the following method signature:

List<Person> findByAddressZipCode(ZipCode zipCode);

Assume a Person has an Address with a ZipCode. In that case, the method creates the property traversal x.address.zipCode. The resolution algorithm starts by interpreting the entire part (AddressZipCode) as the property and checks the domain class for a property with that name (uncapitalized). If the algorithm succeeds, it uses that property. If not, the algorithm splits up the source at the camel case parts from the right side into a head and a tail and tries to find the corresponding property — in our example, AddressZip and Code. If the algorithm finds a property with that head, it takes the tail and continues building the tree down from there, splitting the tail up in the way just described. If the first split does not match, the algorithm moves the split point to the left (Address, ZipCode) and continues.

Although this should work for most cases, it is possible for the algorithm to select the wrong property. Suppose the Person class has an addressZip property as well. The algorithm would match in the first split round already, choose the wrong property, and fail (as the type of addressZip probably has no code property).

To resolve this ambiguity you can use _ inside your method name to manually define traversal points. So our method name would be as follows:

List<Person> findByAddress_ZipCode(ZipCode zipCode);

Because we treat the underscore character as a reserved character, we strongly advise following standard Java naming conventions (that is, not using underscores in property names but using camel case instead).

2.4.4. Special parameter handling

To handle parameters in your query, define method parameters as already seen in the preceding examples. Besides that, the infrastructure recognizes certain specific types like Pageable and Sort, to apply pagination and sorting to your queries dynamically. The following example demonstrates these features:

Example 12. Using Pageable, Slice, and Sort in query methods
Page<User> findByLastname(String lastname, Pageable pageable);

Slice<User> findByLastname(String lastname, Pageable pageable);

List<User> findByLastname(String lastname, Sort sort);

List<User> findByLastname(String lastname, Pageable pageable);

The first method lets you pass an org.springframework.data.domain.Pageable instance to the query method to dynamically add paging to your statically defined query. A Page knows about the total number of elements and pages available. It does so by the infrastructure triggering a count query to calculate the overall number. As this might be expensive (depending on the store used), you can instead return a Slice. A Slice only knows about whether a next Slice is available, which might be sufficient when walking through a larger result set.

Sorting options are handled through the Pageable instance, too. If you only need sorting, add an org.springframework.data.domain.Sort parameter to your method. As you can see, returning a List is also possible. In this case, the additional metadata required to build the actual Page instance is not created (which, in turn, means that the additional count query that would have been necessary is not issued). Rather, it restricts the query to look up only the given range of entities.

To find out how many pages you get for an entire query, you have to trigger an additional count query. By default, this query is derived from the query you actually trigger.

2.4.5. Limiting Query Results

The results of query methods can be limited by using the first or top keywords, which can be used interchangeably. An optional numeric value can be appended to top or first to specify the maximum result size to be returned. If the number is left out, a result size of 1 is assumed. The following example shows how to limit the query size:

Example 13. Limiting the result size of a query with Top and First
User findFirstByOrderByLastnameAsc();

User findTopByOrderByAgeDesc();

Page<User> queryFirst10ByLastname(String lastname, Pageable pageable);

Slice<User> findTop3ByLastname(String lastname, Pageable pageable);

List<User> findFirst10ByLastname(String lastname, Sort sort);

List<User> findTop10ByLastname(String lastname, Pageable pageable);

The limiting expressions also support the Distinct keyword. Also, for the queries limiting the result set to one instance, wrapping the result into with the Optional keyword is supported.

If pagination or slicing is applied to a limiting query pagination (and the calculation of the number of pages available), it is applied within the limited result.

Limiting the results in combination with dynamic sorting by using a Sort parameter lets you express query methods for the 'K' smallest as well as for the 'K' biggest elements.

2.4.6. Streaming query results

The results of query methods can be processed incrementally by using a Java 8 Stream<T> as return type. Instead of wrapping the query results in a Stream data store-specific methods are used to perform the streaming, as shown in the following example:

Example 14. Stream the result of a query with Java 8 Stream<T>
@Query("select u from User u")
Stream<User> findAllByCustomQueryAndStream();

Stream<User> readAllByFirstnameNotNull();

@Query("select u from User u")
Stream<User> streamAllPaged(Pageable pageable);
A Stream potentially wraps underlying data store-specific resources and must, therefore, be closed after usage. You can either manually close the Stream by using the close() method or by using a Java 7 try-with-resources block, as shown in the following example:
Example 15. Working with a Stream<T> result in a try-with-resources block
try (Stream<User> stream = repository.findAllByCustomQueryAndStream()) {
  stream.forEach(…);
}
Not all Spring Data modules currently support Stream<T> as a return type.

2.4.7. Async query results

Repository queries can be run asynchronously by using Spring’s asynchronous method execution capability. This means the method returns immediately upon invocation while the actual query execution occurs in a task that has been submitted to a Spring TaskExecutor. Asynchronous query execution is different from reactive query execution and should not be mixed. Refer to store-specific documentation for more details on reactive support. The following example shows a number of asynchronous queries:

@Async
Future<User> findByFirstname(String firstname);               (1)

@Async
CompletableFuture<User> findOneByFirstname(String firstname); (2)

@Async
ListenableFuture<User> findOneByLastname(String lastname);    (3)
1 Use java.util.concurrent.Future as the return type.
2 Use a Java 8 java.util.concurrent.CompletableFuture as the return type.
3 Use a org.springframework.util.concurrent.ListenableFuture as the return type.

2.5. Creating Repository Instances

In this section, you create instances and bean definitions for the defined repository interfaces. One way to do so is by using the Spring namespace that is shipped with each Spring Data module that supports the repository mechanism, although we generally recommend using Java configuration.

2.5.1. XML configuration

Each Spring Data module includes a repositories element that lets you define a base package that Spring scans for you, as shown in the following example:

Example 16. Enabling Spring Data repositories via XML
<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns:beans="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns="http://www.springframework.org/schema/data/jpa"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/data/jpa
    http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">

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

</beans:beans>

In the preceding example, Spring is instructed to scan com.acme.repositories and all its sub-packages for interfaces extending Repository or one of its sub-interfaces. For each interface found, the infrastructure registers the persistence technology-specific FactoryBean to create the appropriate proxies that handle invocations of the query methods. Each bean is registered under a bean name that is derived from the interface name, so an interface of UserRepository would be registered under userRepository. The base-package attribute allows wildcards so that you can define a pattern of scanned packages.

Using filters

By default, the infrastructure picks up every interface extending the persistence technology-specific Repository sub-interface located under the configured base package and creates a bean instance for it. However, you might want more fine-grained control over which interfaces have bean instances created for them. To do so, use <include-filter /> and <exclude-filter /> elements inside the <repositories /> element. The semantics are exactly equivalent to the elements in Spring’s context namespace. For details, see the Spring reference documentation for these elements.

For example, to exclude certain interfaces from instantiation as repository beans, you could use the following configuration:

Example 17. Using exclude-filter element
<repositories base-package="com.acme.repositories">
  <context:exclude-filter type="regex" expression=".*SomeRepository" />
</repositories>

The preceding example excludes all interfaces ending in SomeRepository from being instantiated.

2.5.2. JavaConfig

The repository infrastructure can also be triggered by using a store-specific @Enable${store}Repositories annotation on a JavaConfig class. For an introduction into Java-based configuration of the Spring container, see JavaConfig in the Spring reference documentation.

A sample configuration to enable Spring Data repositories resembles the following:

Example 18. Sample annotation based repository configuration
@Configuration
@EnableJpaRepositories("com.acme.repositories")
class ApplicationConfiguration {

  @Bean
  public EntityManagerFactory entityManagerFactory() {
    // …
  }
}
The preceding example uses the JPA-specific annotation, which you would change according to the store module you actually use. The same applies to the definition of the EntityManagerFactory bean. See the sections covering the store-specific configuration.

2.5.3. Standalone usage

You can also use the repository infrastructure outside of a Spring container — for example, in CDI environments. You still need some Spring libraries in your classpath, but, generally, you can set up repositories programmatically as well. The Spring Data modules that provide repository support ship a persistence technology-specific RepositoryFactory that you can use as follows:

Example 19. Standalone usage of repository factory
RepositoryFactorySupport factory = … // Instantiate factory here
UserRepository repository = factory.getRepository(UserRepository.class);

2.6. Custom implementations for Spring Data repositories

Often it is necessary to provide a custom implementation for a few repository methods. Spring Data repositories easily allow you to provide custom repository code and integrate it with generic CRUD abstraction and query method functionality.

2.6.1. Adding custom behavior to single repositories

To enrich a repository with custom functionality you first define an interface and an implementation for the custom functionality. Use the repository interface you provided to extend the custom interface.

Example 20. Interface for custom repository functionality
interface UserRepositoryCustom {
  public void someCustomMethod(User user);
}

Then you can let your repository interface additionally extend from the fragment interface, as shown in the following example:

Example 21. Implementation of custom repository functionality
class UserRepositoryImpl implements UserRepositoryCustom {

  public void someCustomMethod(User user) {
    // Your custom implementation
  }
}
The most important bit for the class to be found is the Impl postfix of the name on it compared to the core repository interface (see below).

The implementation itself does not depend on Spring Data and can be a regular Spring bean. Consequently, you can use standard dependency injection behavior to inject references to other beans (such as a JdbcTemplate), take part in aspects, and so on.

You can let your repository interface extend the fragment interface, as shown in the following example:

Example 22. Changes to the your basic repository interface
interface UserRepository extends CrudRepository<User, Long>, UserRepositoryCustom {

  // Declare query methods here
}

Let your standard repository interface extend the custom one. Doing so combines the CRUD and custom functionality and makes it available to clients.

Configuration

If you use namespace configuration, the repository infrastructure tries to autodetect custom implementations by scanning for classes below the package we found a repository in. These classes need to follow the naming convention of appending the namespace element’s attribute repository-impl-postfix to the found repository interface name. This postfix defaults to Impl.

Example 23. Configuration example
<repositories base-package="com.acme.repository" />

<repositories base-package="com.acme.repository" repository-impl-postfix="MyPostfix" />

The first configuration example tries to look up a class com.acme.repository.UserRepositoryImpl to act as custom repository implementation, whereas the second example will try to lookup com.acme.repository.UserRepositoryFooBar.

Manual Wiring

If your custom implementation uses annotation-based configuration and autowiring only, the preceding approach shown works well, because it is treated as any other Spring bean. If your custom implementation bean needs special wiring, you can declare the bean and name it according to the conventions described in the preceding section. The infrastructure then refers to the manually defined bean definition by name instead of creating one itself. The following example shows how to manually wire a custom implementation:

Example 24. Manual wiring of custom implementations
<repositories base-package="com.acme.repository" />

<beans:bean id="userRepositoryImpl" class="…">
  <!-- further configuration -->
</beans:bean>

2.6.2. Adding custom behavior to all repositories

The preceding approach is not feasible when you want to add a single method to all your repository interfaces. To add custom behavior to all repositories, you first add an intermediate interface to declare the shared behavior.

Example 25. An interface declaring custom shared behavior
@NoRepositoryBean
public interface MyRepository<T, ID extends Serializable>
  extends PagingAndSortingRepository<T, ID> {

  void sharedCustomMethod(ID id);
}

Now your individual repository interfaces will extend this intermediate interface instead of the Repository interface to include the functionality declared. Next, create an implementation of the intermediate interface that extends the persistence technology-specific repository base class. This class will then act as a custom base class for the repository proxies.

Example 26. Custom repository base class
public class MyRepositoryImpl<T, ID extends Serializable>
  extends SimpleJpaRepository<T, ID> implements MyRepository<T, ID> {

  private final EntityManager entityManager;

  public MyRepositoryImpl(JpaEntityInformation entityInformation,
                          EntityManager entityManager) {
    super(entityInformation, entityManager);

    // Keep the EntityManager around to used from the newly introduced methods.
    this.entityManager = entityManager;
  }

  public void sharedCustomMethod(ID id) {
    // implementation goes here
  }
}
The class needs to have a constructor of the super class which the store-specific repository factory implementation uses. If the repository base class has multiple constructors, override the one taking an EntityInformation plus a store specific infrastructure object (such as an EntityManager or a template class).

The default behavior of the Spring <repositories /> namespace is to provide an implementation for all interfaces that fall under the base-package. This means that if left in its current state, an implementation instance of MyRepository will be created by Spring. This is of course not desired as it is just supposed to act as an intermediary between Repository and the actual repository interfaces you want to define for each entity. To exclude an interface that extends Repository from being instantiated as a repository instance, you can either annotate it with @NoRepositoryBean (as seen above) or move it outside of the configured base-package.

The final step is to make the Spring Data infrastructure aware of the customized repository base class. In Java configuration, you can do so by using the repositoryBaseClass attribute of the @Enable${store}Repositories annotation, as shown in the following example:

Example 27. Configuring a custom repository base class using JavaConfig
@Configuration
@EnableJpaRepositories(repositoryBaseClass = MyRepositoryImpl.class)
class ApplicationConfiguration { … }

A corresponding attribute is available in the XML namespace, as shown in the following example:

Example 28. Configuring a custom repository base class using XML
<repositories base-package="com.acme.repository"
     base-class="….MyRepositoryImpl" />

2.7. Publishing Events from Aggregate Roots

Entities managed by repositories are aggregate roots. In a Domain-Driven Design application, these aggregate roots usually publish domain events. Spring Data provides an annotation called @DomainEvents that you can use on a method of your aggregate root to make that publication as easy as possible, as shown in the following example:

Example 29. Exposing domain events from an aggregate root
class AnAggregateRoot {

    @DomainEvents (1)
    Collection<Object> domainEvents() {
        // … return events you want to get published here
    }

    @AfterDomainEventsPublication (2)
    void callbackMethod() {
       // … potentially clean up domain events list
    }
}
1 The method using @DomainEvents can return either a single event instance or a collection of events. It must not take any arguments.
2 After all events have been published, we have a method annotated with @AfterDomainEventsPublication. It can be used to potentially clean the list of events to be published (among other uses).

The methods are called every time one of a Spring Data repository’s save(…) methods is called.

2.8. Spring Data Extensions

This section documents a set of Spring Data extensions that enable Spring Data usage in a variety of contexts. Currently, most of the integration is targeted towards Spring MVC.

2.8.1. Querydsl Extension

Querydsl is a framework that enables the construction of statically typed SQL-like queries through its fluent API.

Several Spring Data modules offer integration with Querydsl through QueryDslPredicateExecutor, as shown in the following example:

Example 30. QueryDslPredicateExecutor interface
public interface QueryDslPredicateExecutor<T> {

    T findOne(Predicate predicate);             (1)

    Iterable<T> findAll(Predicate predicate);   (2)

    long count(Predicate predicate);            (3)

    boolean exists(Predicate predicate);        (4)

    // … more functionality omitted.
}
1 Finds and returns a single entity matching the Predicate.
2 Finds and returns all entities matching the Predicate.
3 Returns the number of entities matching the Predicate.
4 Returns whether an entity that matches the Predicate exists.

To make use of Querydsl support, extend QueryDslPredicateExecutor on your repository interface, as shown in the following example

Example 31. Querydsl integration on repositories
interface UserRepository extends CrudRepository<User, Long>, QueryDslPredicateExecutor<User> {
}

The preceding example lets you write typesafe queries using Querydsl Predicate instances, as shown in the following example:

Predicate predicate = user.firstname.equalsIgnoreCase("dave")
	.and(user.lastname.startsWithIgnoreCase("mathews"));

userRepository.findAll(predicate);

2.8.2. Web support

This section contains the documentation for the Spring Data web support as it is implemented in the current (and later) versions of Spring Data Commons. As the newly introduced support changes many things, we kept the documentation of the former behavior in Legacy web support.

Spring Data modules that support the repository programming model ship with a variety of web support. The web related components require Spring MVC JARs to be on the classpath. Some of them even provide integration with Spring HATEOAS. In general, the integration support is enabled by using the @EnableSpringDataWebSupport annotation in your JavaConfig configuration class, as shown in the following example:

Example 32. Enabling Spring Data web support
@Configuration
@EnableWebMvc
@EnableSpringDataWebSupport
class WebConfiguration { }

The @EnableSpringDataWebSupport annotation registers a few components we will discuss in a bit. It will also detect Spring HATEOAS on the classpath and register integration components for it as well if present.

Alternatively, if you use XML configuration, register either SpringDataWebConfiguration or HateoasAwareSpringDataWebConfiguration as Spring beans, as shown in the following example (for SpringDataWebConfiguration):

Example 33. Enabling Spring Data web support in XML
<bean class="org.springframework.data.web.config.SpringDataWebConfiguration" />

<!-- If you use Spring HATEOAS, register this one *instead* of the former -->
<bean class="org.springframework.data.web.config.HateoasAwareSpringDataWebConfiguration" />
Basic Web Support

The configuration shown in the previous section registers a few basic components:

  • A DomainClassConverter to let Spring MVC resolve instances of repository-managed domain classes from request parameters or path variables.

  • HandlerMethodArgumentResolver implementations to let Spring MVC resolve Pageable and Sort instances from request parameters.

DomainClassConverter

The DomainClassConverter lets you use domain types in your Spring MVC controller method signatures directly, so that you need not manually lookup the instances through the repository, as shown in the following example:

Example 34. A Spring MVC controller using domain types in method signatures
@Controller
@RequestMapping("/users")
public class UserController {

  @RequestMapping("/{id}")
  public String showUserForm(@PathVariable("id") User user, Model model) {

    model.addAttribute("user", user);
    return "userForm";
  }
}

As you can see, the method receives a User instance directly, and no further lookup is necessary. The instance can be resolved by letting Spring MVC convert the path variable into the id type of the domain class first and eventually access the instance through calling findOne(…) on the repository instance registered for the domain type.

Currently, the repository has to implement CrudRepository to be eligible to be discovered for conversion.
HandlerMethodArgumentResolvers for Pageable and Sort

The configuration snippet shown in the previous section also registers a PageableHandlerMethodArgumentResolver as well as an instance of SortHandlerMethodArgumentResolver. The registration enables Pageable and Sort as valid controller method arguments, as shown in the following example:

Example 35. Using Pageable as controller method argument
@Controller
@RequestMapping("/users")
public class UserController {

  @Autowired UserRepository repository;

  @RequestMapping
  public String showUsers(Model model, Pageable pageable) {

    model.addAttribute("users", repository.findAll(pageable));
    return "users";
  }
}

The preceding method signature causes Spring MVC try to derive a Pageable instance from the request parameters by using the following default configuration:

Table 1. Request parameters evaluated for Pageable instances

page

Page you want to retrieve. 0-indexed and defaults to 0.

size

Size of the page you want to retrieve. Defaults to 20.

sort

Properties that should be sorted by in the format property,property(,ASC|DESC). Default sort direction is ascending. Use multiple sort parameters if you want to switch directions — for example, ?sort=firstname&sort=lastname,asc.

To customize this behavior extend either SpringDataWebConfiguration or the HATEOAS-enabled equivalent and override the pageableResolver() or sortResolver() methods and import your customized configuration file instead of using the @Enable-annotation.

If you need multiple Pageable or Sort instances to be resolved from the request (for multiple tables, for example), you can use Spring’s @Qualifier annotation to distinguish one from another. The request parameters then have to be prefixed with ${qualifier}_. The followig example shows the resulting method signature:

public String showUsers(Model model,
      @Qualifier("thing1") Pageable first,
      @Qualifier("thing2") Pageable second) { … }

you have to populate thing1_page and thing2_page and so on.

The default Pageable passed into the method is equivalent to a new PageRequest(0, 20) but can be customized by using the @PageableDefault annotation on the Pageable parameter.

Hypermedia Support for Pageables

Spring HATEOAS ships with a representation model class (PagedResources) that allows enriching the content of a Page instance with the necessary Page metadata as well as links to let the clients easily navigate the pages. The conversion of a Page to a PagedResources is done by an implementation of the Spring HATEOAS ResourceAssembler interface, called the PagedResourcesAssembler. The following example shows how to use a PagedResourcesAssembler as a controller method argument:

Example 36. Using a PagedResourcesAssembler as controller method argument
@Controller
class PersonController {

  @Autowired PersonRepository repository;

  @RequestMapping(value = "/persons", method = RequestMethod.GET)
  HttpEntity<PagedResources<Person>> persons(Pageable pageable,
    PagedResourcesAssembler assembler) {

    Page<Person> persons = repository.findAll(pageable);
    return new ResponseEntity<>(assembler.toResources(persons), HttpStatus.OK);
  }
}

Enabling the configuration as shown in the preceding example lets the PagedResourcesAssembler be used as a controller method argument. Calling toResources(…) on it has the following effects:

  • The content of the Page becomes the content of the PagedResources instance.

  • The PagedResources object gets a PageMetadata instance attached, and it is populated with information from the Page and the underlying PageRequest.

  • The PagedResources may get prev and next links attached, depending on the page’s state. The links point to the URI to which the method maps. The pagination parameters added to the method match the setup of the PageableHandlerMethodArgumentResolver to make sure the links can be resolved later.

Assume we have 30 Person instances in the database. You can now trigger a request (GET http://localhost:8080/persons) and see output similar to the following:

{ "links" : [ { "rel" : "next",
                "href" : "http://localhost:8080/persons?page=1&size=20 }
  ],
  "content" : [
     … // 20 Person instances rendered here
  ],
  "pageMetadata" : {
    "size" : 20,
    "totalElements" : 30,
    "totalPages" : 2,
    "number" : 0
  }
}

You see that the assembler produced the correct URI and also picked up the default configuration to resolve the parameters into a Pageable for an upcoming request. This means that, if you change that configuration, the links automatically adhere to the change. By default, the assembler points to the controller method it was invoked in, but that can be customized by handing in a custom Link to be used as base to build the pagination links, which overloads the PagedResourcesAssembler.toResource(…) method.

Web Databinding Support

Spring Data projections (described in [projections]) can be used to bind incoming request payloads by either using JSONPath expressions (requires Jayway JsonPath or XPath expressions (requires XmlBeam), as shown in the following example:

Example 37. HTTP payload binding using JSONPath or XPath expressions
@ProjectedPayload
public interface UserPayload {

  @XBRead("//firstname")
  @JsonPath("$..firstname")
  String getFirstname();

  @XBRead("/lastname")
  @JsonPath({ "$.lastname", "$.user.lastname" })
  String getLastname();
}

The type shown in the preceding example can be used as a Spring MVC handler method argument or by using ParameterizedTypeReference on one of RestTemplate's methods. The preceding method declarations would try to find firstname anywhere in the given document. The lastname XML lookup is performed on the top-level of the incoming document. The JSON variant of that tries a top-level lastname first but also tries lastname nested in a user sub-document if the former does not return a value. That way, changes in the structure of the source document can be mitigated easily without having clients calling the exposed methods (usually a drawback of class-based payload binding).

Nested projections are supported as described in [projections]. If the method returns a complex, non-interface type, a Jackson ObjectMapper is used to map the final value.

For Spring MVC, the necessary converters are registered automatically as soon as @EnableSpringDataWebSupport is active and the required dependencies are available on the classpath. For usage with RestTemplate, register a ProjectingJackson2HttpMessageConverter (JSON) or XmlBeamHttpMessageConverter manually.

For more information, see the web projection example in the canonical Spring Data Examples repository.

Querydsl Web Support

For those stores having QueryDSL integration, it is possible to derive queries from the attributes contained in a Request query string.

Consider the following query string:

?firstname=Dave&lastname=Matthews

Given the User object from previous examples, a query string can be resolved to the following value by using the QuerydslPredicateArgumentResolver.

QUser.user.firstname.eq("Dave").and(QUser.user.lastname.eq("Matthews"))
The feature is automatically enabled, along with @EnableSpringDataWebSupport, when Querydsl is found on the classpath.

Adding a @QuerydslPredicate to the method signature provides a ready-to-use Predicate, which can be run by using the QuerydslPredicateExecutor.

Type information is typically resolved from the method’s return type. Since that information does not necessarily match the domain type, it might be a good idea to use the root attribute of QuerydslPredicate.

The following exampe shows how to use @QuerydslPredicate in a method signature:

@Controller
class UserController {

  @Autowired UserRepository repository;

  @RequestMapping(value = "/", method = RequestMethod.GET)
  String index(Model model, @QuerydslPredicate(root = User.class) Predicate predicate,    (1)
          Pageable pageable, @RequestParam MultiValueMap<String, String> parameters) {

    model.addAttribute("users", repository.findAll(predicate, pageable));

    return "index";
  }
}
1 Resolve query string arguments to matching Predicate for User.

The default binding is as follows:

  • Object on simple properties as eq.

  • Object on collection like properties as contains.

  • Collection on simple properties as in.

Those bindings can be customized through the bindings attribute of @QuerydslPredicate or by making use of Java 8 default methods and adding the QuerydslBinderCustomizer method to the repository interface.

interface UserRepository extends CrudRepository<User, String>,
                                 QueryDslPredicateExecutor<User>,                (1)
                                 QuerydslBinderCustomizer<QUser> {               (2)

  @Override
  default public void customize(QuerydslBindings bindings, QUser user) {

    bindings.bind(user.username).first((path, value) -> path.contains(value))    (3)
    bindings.bind(String.class)
      .first((StringPath path, String value) -> path.containsIgnoreCase(value)); (4)
    bindings.excluding(user.password);                                           (5)
  }
}
1 QueryDslPredicateExecutor provides access to specific finder methods for Predicate.
2 QuerydslBinderCustomizer defined on the repository interface is automatically picked up and shortcuts @QuerydslPredicate(bindings=…​).
3 Define the binding for the username property to be a simple contains binding.
4 Define the default binding for String properties to be a case-insensitive contains match.
5 Exclude the password property from Predicate resolution.

2.8.3. Repository Populators

If you work with the Spring JDBC module, you are probably familiar with the support to populate a DataSource with SQL scripts. A similar abstraction is available on the repositories level, although it does not use SQL as the data definition language because it must be store-independent. Thus, the populators support XML (through Spring’s OXM abstraction) and JSON (through Jackson) to define data with which to populate the repositories.

Assume you have a file data.json with the following content:

Example 38. Data defined in JSON
[ { "_class" : "com.acme.Person",
 "firstname" : "Dave",
  "lastname" : "Matthews" },
  { "_class" : "com.acme.Person",
 "firstname" : "Carter",
  "lastname" : "Beauford" } ]

You can populate your repositories by using the populator elements of the repository namespace provided in Spring Data Commons. To populate the preceding data to your PersonRepository, declare a populator similar to the following:

Example 39. Declaring a Jackson repository populator
<?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:repository="http://www.springframework.org/schema/data/repository"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/data/repository
    http://www.springframework.org/schema/data/repository/spring-repository.xsd">

  <repository:jackson2-populator locations="classpath:data.json" />

</beans>

The preceding declaration causes the data.json file to be read and deserialized by a Jackson ObjectMapper.

The type to which the JSON object is unmarshalled is determined by inspecting the _class attribute of the JSON document. The infrastructure eventually selects the appropriate repository to handle the object that was deserialized.

To instead use XML to define the data the repositories should be populated with, you can use the unmarshaller-populator element. You configure it to use one of the XML marshaller options available in Spring OXM. See the Spring reference documentation for details. The following example shows how to unmarshal a repository populator with JAXB:

Example 40. Declaring an unmarshalling repository populator (using JAXB)
<?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:repository="http://www.springframework.org/schema/data/repository"
  xmlns:oxm="http://www.springframework.org/schema/oxm"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/data/repository
    http://www.springframework.org/schema/data/repository/spring-repository.xsd
    http://www.springframework.org/schema/oxm
    http://www.springframework.org/schema/oxm/spring-oxm.xsd">

  <repository:unmarshaller-populator locations="classpath:data.json"
    unmarshaller-ref="unmarshaller" />

  <oxm:jaxb2-marshaller contextPath="com.acme" />

</beans>

2.8.4. Legacy web support

Domain class web binding for Spring MVC

Given you are developing a Spring MVC web application you typically have to resolve domain class ids from URLs. By default your task is to transform that request parameter or URL part into the domain class to hand it to layers below then or execute business logic on the entities directly. This would look something like this:

@Controller
@RequestMapping("/users")
public class UserController {

  private final UserRepository userRepository;

  @Autowired
  public UserController(UserRepository userRepository) {
    Assert.notNull(repository, "Repository must not be null!");
    this.userRepository = userRepository;
  }

  @RequestMapping("/{id}")
  public String showUserForm(@PathVariable("id") Long id, Model model) {

    // Do null check for id
    User user = userRepository.findOne(id);
    // Do null check for user

    model.addAttribute("user", user);
    return "user";
  }
}

First you declare a repository dependency for each controller to look up the entity managed by the controller or repository respectively. Looking up the entity is boilerplate as well, as it’s always a findOne(…) call. Fortunately Spring provides means to register custom components that allow conversion between a String value to an arbitrary type.

PropertyEditors

For Spring versions before 3.0 simple Java PropertyEditors had to be used. To integrate with that, Spring Data offers a DomainClassPropertyEditorRegistrar, which looks up all Spring Data repositories registered in the ApplicationContext and registers a custom PropertyEditor for the managed domain class.

<bean class="….web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
  <property name="webBindingInitializer">
    <bean class="….web.bind.support.ConfigurableWebBindingInitializer">
      <property name="propertyEditorRegistrars">
        <bean class="org.springframework.data.repository.support.DomainClassPropertyEditorRegistrar" />
      </property>
    </bean>
  </property>
</bean>

If you have configured Spring MVC as in the preceding example, you can configure your controller as follows, which reduces a lot of the clutter and boilerplate.

@Controller
@RequestMapping("/users")
public class UserController {

  @RequestMapping("/{id}")
  public String showUserForm(@PathVariable("id") User user, Model model) {

    model.addAttribute("user", user);
    return "userForm";
  }
}

Reference Documentation

3. Solr Repositories

This chapter includes details of the Solr repository implementation.

3.1. Introduction

3.1.1. Spring Namespace

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

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

Example 41. Setting up Solr 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:solr="http://www.springframework.org/schema/data/solr"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/data/solr
    http://www.springframework.org/schema/data/solr/spring-solr.xsd">

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

Using the solr-server or embedded-solr-server element registers an instance of SolrClient in the context.

Example 42. HttpSolrClient 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:solr="http://www.springframework.org/schema/data/solr"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/data/solr
    http://www.springframework.org/schema/data/solr/spring-solr.xsd">

  <solr:solr-client id="solrClient" url="http://locahost:8983/solr" />
</beans>
Example 43. LBSolrClient 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:solr="http://www.springframework.org/schema/data/solr"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/data/solr
    http://www.springframework.org/schema/data/solr/spring-solr.xsd">

  <solr:solr-client id="solrClient" url="http://locahost:8983/solr,http://localhost:8984/solr" />
</beans>
Example 44. EmbeddedSolrServer 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:solr="http://www.springframework.org/schema/data/solr"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/data/solr
    http://www.springframework.org/schema/data/solr/spring-solr.xsd">

  <solr:embedded-solr-server id="solrClient" solrHome="classpath:com/acme/solr" />
</beans>

3.1.2. Annotation based configuration

The Spring Data Solr repositories support cannot only be activated through an XML namespace but also using an annotation through JavaConfig.

Example 45. Spring Data Solr repositories using JavaConfig
@Configuration
@EnableSolrRepositories
class ApplicationConfig {

  @Bean
  public SolrClient solrClient() {
    EmbeddedSolrServerFactory factory = new EmbeddedSolrServerFactory("classpath:com/acme/solr");
    return factory.getSolrServer();
  }

  @Bean
  public SolrOperations solrTemplate() {
    return new SolrTemplate(solrClient());
  }
}

The configuration above sets up an EmbeddedSolrServer which is used by the SolrTemplate . Spring Data Solr Repositories are activated using the @EnableSolrRepositories annotation, which essentially carries the same attributes as the XML namespace does. If no base package is configured, it will use the one the configuration class resides in.

3.1.3. Multicore Support

Solr handles different collections within one core. Use MulticoreSolrClientFactory to create separate SolrClient for each core.

Example 46. Multicore Configuration
@Configuration
@EnableSolrRepositories(multicoreSupport = true)
class ApplicationConfig {

  private static final String PROPERTY_NAME_SOLR_SERVER_URL = "solr.host";

  @Resource
  private Environment environment;

  @Bean
  public SolrClient solrClient() {
    return new HttpSolrClient(environment.getRequiredProperty(PROPERTY_NAME_SOLR_SERVER_URL));
  }

}

3.1.4. Solr Repositores using CDI

The Spring Data Solr repositories can also be set up using CDI functionality.

Example 47. Spring Data Solr repositories using JavaConfig
class SolrTemplateProducer {

  @Produces
  @ApplicationScoped
  public SolrOperations createSolrTemplate() {
    return new SolrTemplate(new EmbeddedSolrServerFactory("classpath:com/acme/solr"));
  }
}

class ProductService {

  private ProductRepository repository;

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

  @Inject
  public void setRepository(ProductRepository repository) {
    this.repository = repository;
  }
}

3.1.5. Transaction Support

Solr supports transactions on server level means create, updaet, delete actions since the last commit/optimize/rollback are queued on the server and committed/optimized/rolled back at once. Spring Data Solr Repositories will participate in Spring Managed Transactions and commit/rollback changes on complete.

@Transactional
public Product save(Product product) {
  Product savedProduct = jpaRepository.save(product);
  solrRepository.save(savedProduct);
  return savedProduct;
}

3.2. Query methods

3.2.1. Query lookup strategies

The Solr module supports defining a query manually as String or have it being derived from the method name. NOTE: There is no QueryDSL Support present at this time.

Declared queries

Deriving the query from the method name is not always sufficient and/or may result in unreadable method names. In this case one might make either use of Solr named queries (see Using NamedQueries ) or use the @Query annotation (see Using @Query Annotation ).

3.2.2. Query creation

Generally the query creation mechanism for Solr works as described in Query methods . Here’s a short example of what a Solr query method translates into:

Example 48. Query creation from method names
public interface ProductRepository extends Repository<Product, String> {
  List<Product> findByNameAndPopularity(String name, Integer popularity);
}

The method name above will be translated into the following solr query

q=name:?0 AND popularity:?1

A list of supported keywords for Solr is shown below.

Table 2. Supported keywords inside method names
Keyword Sample Solr Query String

And

findByNameAndPopularity

q=name:?0 AND popularity:?1

Or

findByNameOrPopularity

q=name:?0 OR popularity:?1

Is

findByName

q=name:?0

Not

findByNameNot

q=-name:?0

IsNull

findByNameIsNull

q=-name:[* TO *]

IsNotNull

findByNameIsNotNull

q=name:[* TO *]

Between

findByPopularityBetween

q=popularity:[?0 TO ?1]

LessThan

findByPopularityLessThan

q=popularity:[* TO ?0}

LessThanEqual

findByPopularityLessThanEqual

q=popularity:[* TO ?0]

GreaterThan

findByPopularityGreaterThan

q=popularity:{?0 TO *]

GreaterThanEqual

findByPopularityGreaterThanEqual

q=popularity:[?0 TO *]

Before

findByLastModifiedBefore

q=last_modified:[* TO ?0}

After

findByLastModifiedAfter

q=last_modified:{?0 TO *]

Like

findByNameLike

q=name:?0*

NotLike

findByNameNotLike

q=-name:?0*

StartingWith

findByNameStartingWith

q=name:?0*

EndingWith

findByNameEndingWith

q=name:*?0

Containing

findByNameContaining

q=name:*?0*

Matches

findByNameMatches

q=name:?0

In

findByNameIn(Collection<String> names)

q=name:(?0…​ )

NotIn

findByNameNotIn(Collection<String> names)

q=-name:(?0…​ )

Within

findByStoreWithin(Point, Distance)

q={!geofilt pt=?0.latitude,?0.longitude sfield=store d=?1}

Near

findByStoreNear(Point, Distance)

q={!bbox pt=?0.latitude,?0.longitude sfield=store d=?1}

Near

findByStoreNear(Box)

q=store[?0.start.latitude,?0.start.longitude TO ?0.end.latitude,?0.end.longitude]

True

findByAvailableTrue

q=inStock:true

False

findByAvailableFalse

q=inStock:false

OrderBy

findByAvailableTrueOrderByNameDesc

q=inStock:true&sort=name desc

Collections types can be used along with 'Like', 'NotLike', 'StartingWith', 'EndingWith' and 'Containing'.
Page<Product> findByNameLike(Collection<String> name);

3.2.3. Using @Query Annotation

Using named queries ( Using NamedQueries ) to declare queries for entities is a valid approach and works fine for a small number of queries. As the queries themselves are tied to the Java method that executes them, you actually can bind them directly using the Spring Data Solr @Query annotation.

Example 49. Declare query at the method using the @Query annotation.
public interface ProductRepository extends SolrRepository<Product, String> {
  @Query("inStock:?0")
  List<Product> findByAvailable(Boolean available);
}

3.2.4. Using NamedQueries

Named queries can be kept in a properties file and wired to the accroding method. Please mind the naming convention described in Query Lookup Strategies or use @Query .

Example 50. Declare named query in properties file
Product.findByNamedQuery=popularity:?0
Product.findByName=name:?0
public interface ProductRepository extends SolrCrudRepository<Product, String> {

  List<Product> findByNamedQuery(Integer popularity);

  @Query(name = "Product.findByName")
  List<Product> findByAnnotatedNamedQuery(String name);

}

3.3. Document Mapping

Though there is already support for Entity Mapping within SolrJ, Spring Data Solr ships with its own mapping mechanism shown in the following section. NOTE: DocumentObjectBinder has superior performance. Therefore usage is recommended if there is not need for custom type mapping. You can switch to DocumentObjectBinder by registering SolrJConverter within SolrTemplate.

3.3.1. Mapping Solr Converter

MappingSolrConverter allows you to register custom converters for your SolrDocument and SolrInputDocument as well as for other types nested within your beans. The Converter is not 100% compartible with DocumentObjectBinder and @Indexed has to be added with readonly=true to ignore fields from beeing written to solr.

Example 51. Sample Document Mapping
public class Product {
  @Field
  private String simpleProperty;

  @Field("somePropertyName")
  private String namedPropery;

  @Field
  private List<String> listOfValues;

  @Indexed(readonly = true)
  @Field("property_*")
  private List<String> ignoredFromWriting;

  @Field("mappedField_*")
  private Map<String, List<String>> mappedFieldValues;

  @Dynamic
  @Field("dynamicMappedField_*")
  private Map<String, String> dynamicMappedFieldValues;

  @Field
  private GeoLocation location;

}

Taking a look as the above MappingSolrConverter will do as follows:

Property Write Mapping

simpleProperty

<field name="simpleProperty">value</field>

namedPropery

<field name="somePropertyName">value</field>

listOfValues

<field name="listOfValues">value 1</field> <field name="listOfValues">value 2</field> <field name="listOfValues">value 3</field>

ignoredFromWriting

//not written to document

mappedFieldValues

<field name="mapentry[0].key">mapentry[0].value[0]</field> <field name="mapentry[0].key">mapentry[0].value[1]</field> <field name="mapentry[1].key">mapentry[1].value[0]</field>

dynamicMappedFieldValues

<field name="'dynamicMappedField_' + mapentry[0].key">mapentry[0].value[0]</field> <field name="'dynamicMappedField_' + mapentry[0].key">mapentry[0].value[1]</field> <field name="'dynamicMappedField_' + mapentry[1].key">mapentry[1].value[0]</field>

location

<field name="location">48.362893,14.534437</field>

To register a custom converter one must add CustomConversions to SolrTemplate initializing it with own Converter implementation.

<bean id="solrConverter" class="org.springframework.data.solr.core.convert.MappingSolrConverter">
	<constructor-arg>
		<bean class="org.springframework.data.solr.core.mapping.SimpleSolrMappingContext" />
	</constructor-arg>
	<property name="customConversions" ref="customConversions" />
</bean>

<bean id="customConversions" class="org.springframework.data.solr.core.convert.CustomConversions">
	<constructor-arg>
		<list>
			<bean class="com.acme.MyBeanToSolrInputDocumentConverter" />
		</list>
	</constructor-arg>
</bean>

<bean id="solrTemplate" class="org.springframework.data.solr.core.SolrTemplate">
	<constructor-arg ref="solrClient" />
	<property name="solrConverter" ref="solrConverter" />
</bean>

4. Miscellaneous Solr Operation Support

This chapter covers additional support for Solr operations (such as faceting) that cannot be directly accessed via the repository interface. It is recommended to add those operations as custom implementation as described in Custom implementations for Spring Data repositories .

4.1. Partial Updates

PartialUpdates can be done using PartialUpdate which implements Update.

PartialUpdate update = new PartialUpdate("id", "123");
update.add("name", "updated-name");
solrTemplate.saveBean(update);

4.2. Projection

Projections can be applied via @Query using the fields value.

@Query(fields = { "name", "id" })
List<ProductBean> findByNameStartingWith(String name);

4.3. Faceting

Faceting cannot be directly applied using the SolrRepository but the SolrTemplate holds support for this feature.

FacetQuery query = new SimpleFacetQuery(new Criteria(Criteria.WILDCARD).expression(Criteria.WILDCARD))
  .setFacetOptions(new FacetOptions().addFacetOnField("name").setFacetLimit(5));
FacetPage<Product> page = solrTemplate.queryForFacetPage(query, Product.class);

Facets on fields and/or queries can also be defined using @Facet . Please mind that the result will be a FacetPage . NOTE: Using @Facet allows you to define place holders which will use your input parameter as value.

@Query(value = "*:*")
@Facet(fields = { "name" }, limit = 5)
FacetPage<Product> findAllFacetOnName(Pageable page);
@Query(value = "popularity:?0")
@Facet(fields = { "name" }, limit = 5, prefix="?1")
FacetPage<Product> findByPopularityFacetOnName(int popularity, String prefix, Pageable page);

Solr allows definition of facet parameters on a per field basis. In order to add special facet options to defined fields use FieldWithFacetParameters.

// produces: f.name.facet.prefix=spring
FacetOptions options = new FacetOptions();
options.addFacetOnField(new FieldWithFacetParameters("name").setPrefix("spring"));

4.3.1. Range Faceting

Range faceting queries may be done by configure required ranges on FacetOptions. A simple way to request ranges would be by creating a FacetOption, setting this options to a FacetQuery and query for a facet page through SolrTemplate as follows.

FacetOptions facetOptions = new FacetOptions()
  .addFacetByRange(
     new FieldWithNumericRangeParameters("price", 5, 20, 5)
       .setHardEnd(true)
       .setInclude(FacetRangeInclude.ALL)
  )
  .addFacetByRange(
    new FieldWithDateRangeParameters("release", new Date(1420070400), new Date(946684800), "+1YEAR")
      .setInclude(FacetRangeInclude.ALL)
      .setOther(FacetRangeOther.BEFORE)
  );
facetOptions.setFacetMinCount(0);

Criteria criteria = new SimpleStringCriteria("*:*");
SimpleFacetQuery facetQuery = new SimpleFacetQuery(criteria).setFacetOptions(facetOptions);
FacetPage<ExampleSolrBean> statResultPage = solrTemplate.queryForFacetPage(facetQuery, ExampleSolrBean.class);

There are two implementations of fields for facet range requests:

  • Numeric Facet Range - used to perform range faceting over numeric fields. To request such range faceting an instance of the class org.springframework.data.solr.core.query.FacetOptions.FieldWithNumericRangeParameters can be used. Its instantiation requires a field name, a start value (number), end value (number) and gap (number);

  • Date Facet Range - used to perform range faceting over date fields. To request such range faceting an instance of the class org.springframework.data.solr.core.query.FacetOptions.FieldWithDateRangeParameters can be used. Its instantiation requires a field name, a start value (date), end value (date) and gap (string). The gap for this kind of field can be defined using org.apache.solr.util.DateMathParser (i.e. +6MONTHS+3DAYS/DAY, that would mean 6 months and 3 days in the future from now, rounded down to nearest day).

Additionally the following properties can be configured for a field with range parameters (org.springframework.data.solr.core.query.FacetOptions.FieldWithRangeParameters):

  • Hard End - setHardEnd(Boolean), defines if the last range should be abruptly ended even if the end doesn’t satisfies: (start - end) % gap = 0;

  • Include - setInclude(org.apache.solr.common.params.FacetParams.FacetRangeInclude), defines how boundaries (lower and upper) shall be handled (exclusive or inclusive) on range facet requests;

  • Other - setOther(org.apache.solr.common.params.FacetParams.FacetRangeOther), defines the additional (other) counts for the range facet, i.e. count of documents that are before start of the range facet, end of range facet or even between start and end.

4.3.2. Pivot Faceting

Pivot faceting (Decision Tree) are also supported, and can be queried using @Facet annotation as follows:

public interface {

	@Facet(pivots = @Pivot({ "category", "dimension" }, pivotMinCount = 0))
	FacetPage<Product> findByTitle(String title, Pageable page);

	@Facet(pivots = @Pivot({ "category", "dimension" }))
	FacetPage<Product> findByDescription(String description, Pageable page);

}

Alternatively it can be queried using SolrTemplate as follows:

FacetQuery facetQuery = new SimpleFacetQuery(new SimpleStringCriteria("title:foo"));
FacetOptions facetOptions = new FacetOptions();
facetOptions.setFacetMinCount(0);
facetOptions.addFacetOnPivot("category","dimension");
facetQuery.setFacetOptions(facetOptions);
FacetPage<Product> facetResult = solrTemplate.queryForFacetPage(facetQuery, Product.class);

In order to retrieve the pivot results the method getPivot can be used as follows:

List<FacetPivotFieldEntry> pivot = facetResult.getPivot(new SimplePivotField("categories","available"));

4.4. Terms

Terms Vector cannot directly be used within SolrRepository but can be applied via SolrTemplate. Please mind, that the result will be a TermsPage.

TermsQuery query = SimpleTermsQuery.queryBuilder().fields("name").build();
TermsPage page = solrTemplate.queryForTermsPage(query);

4.5. Result Grouping / Field Collapsing

Result grouping cannot directly be used within SolrRepository but can be applied via SolrTemplate. Please mind, that the result will be a GroupPage.

Field field = new SimpleField("popularity");
Function func = ExistsFunction.exists("description");
Query query = new SimpleQuery("inStock:true");

SimpleQuery groupQuery = new SimpleQuery(new SimpleStringCriteria("*:*"));
GroupOptions groupOptions = new GroupOptions()
	.addGroupByField(field)
	.addGroupByFunction(func)
	.addGroupByQuery(query);
groupQuery.setGroupOptions(groupOptions);

GroupPage<Product> page = solrTemplate.queryForGroupPage(query, Product.class);

GroupResult<Product> fieldGroup = page.getGroupResult(field);
GroupResult<Product> funcGroup = page.getGroupResult(func);
GroupResult<Product> queryGroup = page.getGroupResult(query);

4.6. Field Stats

Field stats are used to retrieve statistics (max, min, sum, count, mean, missing, stddev and distinct calculations) of given fields from Solr. It is possible by providing StatsOptions to your query and reading the FieldStatsResult from the returned StatsPage. This could be achieved for instance, using SolrTemplate as follows:

// simple field stats
StatsOptions statsOptions = new StatsOptions().addField("price");

// query
SimpleQuery statsQuery = new SimpleQuery("*:*");
statsQuery.setStatsOptions(statsOptions);
StatsPage<Product> statsPage = solrTemplate.queryForStatsPage(statsQuery, Product.class);

// retrieving stats info
FieldStatsResult priceStatResult = statResultPage.getFieldStatsResult("price");
Object max = priceStatResult.getMax();
Long missing = priceStatResult.getMissing();

The same result could be achieved annotating the repository method with @Stats as follows:

@Query("name:?0")
@Stats(value = { "price" })
StatsPage<Product> findByName(String name, Pageable page);

Distinct calculation and faceting are also supported:

// for distinct calculation
StatsOptions statsOptions = new StatsOptions()
    .addField("category")
    // for distinct calculation
    .setCalcDistinct(true)
    // for faceting
    .addFacet("availability");

// query
SimpleQuery statsQuery = new SimpleQuery("*:*");
statsQuery.setStatsOptions(statsOptions);
StatsPage<Product> statsPage = solrTemplate.queryForStatsPage(statsQuery, Product.class);

// field stats
FieldStatsResult categoryStatResult = statResultPage.getFieldStatsResult("category");

// retrieving distinct
List<Object> categoryValues = priceStatResult.getDistinctValues();
Long distinctCount = categoryStatResult.getDistinctCount();

// retrieving faceting
Map<String, StatsResult> availabilityFacetResult = categoryStatResult.getFacetStatsResult("availability");
Long availableCount = availabilityFacetResult.get("true").getCount();

The annotated version of the sample above would be:

@Query("name:?0")
@Stats(value = "category", facets = { "availability" }, calcDistinct = true)
StatsPage<Product> findByName(String name);

In order to perform a selective faceting or selective distinct calculation, @SelectiveStats may be used as follows:

// selective distinct faceting
...
Field facetField = getFacetField();
StatsOptions statsOptions = new StatsOptions()
    .addField("price")
    .addField("category").addSelectiveFacet("name").addSelectiveFacet(facetField);
...
// or annotating repository method as follows
...
@Stats(value = "price", selective = @SelectiveStats(field = "category", facets = { "name", "available" }))
...

// selective distinct calculation
...
StatsOptions statsOptions = new StatsOptions()
    .addField("price")
    .addField("category").setSelectiveCalcDistinct(true);
...
// or annotating repository method as follows
...
@Stats(value = "price", selective = @SelectiveStats(field = "category", calcDistinct = true))
...

4.7. Filter Query

Filter Queries improve query speed and do not influence document score. It is recommended to implement geospatial search as filter query. NOTE: Please note that in solr, unless otherwise specified, all units of distance are kilometers and points are in degrees of latitude,longitude.

Query query = new SimpleQuery(new Criteria("category").is("supercalifragilisticexpialidocious"));
FilterQuery fq = new SimpleFilterQuery(new Criteria("store")
  .near(new Point(48.305478, 14.286699), new Distance(5)));
query.addFilterQuery(fq);

Simple filter queries can also be defined using @Query . NOTE: Using @Query allows you to define place holders which will use your input parameter as value.

@Query(value = "*:*", filters = { "inStock:true", "popularity:[* TO 3]" })
List<Product> findAllFilterAvailableTrueAndPopularityLessThanEqual3();

4.8. Time allowed for a search

It it possible to set the time allowed for a search to finish. This value only applies to the search and not to requests in general. Time is in milliseconds. Values less than or equal to zero implies no time restriction. Partial results may be returned, if there are any.

Query query = new SimpleQuery(new SimpleStringCriteria("field_1:value_1"));
// Allowing maximum of 100ms for this search
query.setTimeAllowed(100);

4.9. Boost document Score

Boost document score in case of matching criteria to influence result order. This can be done by either setting boost on Criteria or using @Boost for derived queries.

Page<Product> findByNameOrDescription(@Boost(2) String name, String description);

4.9.1. Index Time Boosts

Boosting documents score can be done on index time by using @SolrDocument annotation on classes (for Solr documents) and/or @Indexed on fields (for Solr fields).

import org.apache.solr.client.solrj.beans.Field;
import org.springframework.data.solr.repository.Boost;

@SolrDocument(boost = 0.8f)
public class MyEntity {

    @Id
    @Indexed
    private String id;

    @Indexed(boost = 1.0f)
    private String name;

    // setters and getters ...

}

4.10. Select Request Handler

Select the request handler via qt Parameter directly in Query or add @Query to your method signature.

@Query(requestHandler = "/instock")
Page<Product> findByNameOrDescription(String name, String description);

4.11. Using Join

Join attributes within one solr core by defining Join attribute of Query. NOTE: Join is not available prior to solr 4.x.

SimpleQuery query = new SimpleQuery(new SimpleStringCriteria("text:ipod"));
query.setJoin(Join.from("manu_id_s").to("id"));

4.12. Highlighting

To highlight matches in search result add HighlightOptions to the SimpleHighlightQuery. Providing HighlightOptions without any further attributes will highlight apply highlighting on all fields within a SolrDocument. NOTE: Field specific highlight parameters can be set by adding FieldWithHighlightParameters to HighlightOptions.

SimpleHighlightQuery query = new SimpleHighlightQuery(new SimpleStringCriteria("name:with"));
query.setHighlightOptions(new HighlightOptions());
HighlightPage<Product> page = solrTemplate.queryForHighlightPage(query, Product.class);

Not all parameters are available via setters/getters but can be added directly.

SimpleHighlightQuery query = new SimpleHighlightQuery(new SimpleStringCriteria("name:with"));
query.setHighlightOptions(new HighlightOptions().addHighlightParameter("hl.bs.country", "at"));

In order to apply Highlighting to derived queries use @Highlight. If no fields are defined highlighting will be aplied on all fields.

@Highlight(prefix = "<b>", postfix = "</b>")
HighlightPage<Product> findByName(String name, Pageable page);

4.13. Spellchecking

Spellchecking offers search term suggestions based on the actual query. Please see the Solr Reference for more details.

4.13.1. Spellecheck Options

Spellcheck query parameters are added to request when SpellcheckOptions are set.

SimpleQuery q = new SimpleQuery("name:gren");
q.setSpellcheckOptions(SpellcheckOptions.spellcheck()               (1)
  .dictionaries("dict1", "dict2")                                   (2)
  .count(5)                                                         (3)
  .extendedResults());                                              (4)
q.setRequestHandler("/spell");                                      (5)

SpellcheckedPage<Product> found = template.query(q, Product.class); (6)
1 Enable spellcheck by setting SpellcheckOptions. Sets spellcheck=on request parameter.
2 Set up the dictionaries to use for lookup.
3 Set the max number of suggestions to return.
4 Enable extended results including term frequency etc.
5 Set the request handler capable of processing suggestions.
6 Execute the query.

4.13.2. @Spellcheck

The @Spellcheck annotations allows usage of the spellcheck feature on Repository level.

public interface ProductRepository extends Repository<Product, String> {

  @Query(requestHandler = "/spell")
  @Spellcheck(dictionaries = { "dict1", "dic2" }, count=5, extendedResults = true)
  SpellcheckedPage<Product> findByName(String name, Pageable page);

}

4.14. Using Functions

Solr supports several functional expressions within queries. Followig functions are supported out of the box. Custom functions can be added by implementing Function

Table 3. Functions
Class Solr Function

CurrencyFunction

currency(field_name,[CODE])

DefaultValueFunction

def(field|function,defaultValue)

DistanceFunction

dist(power, pointA, pointB)

DivideFunction

div(x,y)

ExistsFunction

exists(field|function)

GeoDistanceFunction

geodist(sfield, latitude, longitude)

GeoHashFunction

geohash(latitude, longitude)

IfFunction

if(value|field|function,trueValue,falseValue)

MaxFunction

max(field|function,value)

NotFunction

not(field|function)

ProductFunction

product(x,y,…​)

QueryFunction

query(x)

TermFrequencyFunction

termfreq(field,term)

SimpleQuery query = new SimpleQuery(new SimpleStringCriteria("text:ipod"));
query.addFilterQuery(new FilterQuery(Criteria.where(QueryFunction.query("name:sol*"))));

4.15. Realtime Get

The realtime get allows retrieval of the latest version of any document using the unique-key, without the need to reopen searchers.

realtime get relies on the update log feature.
Example 52. Realtime get
Product product = solrTemplate.getById("123", Product.class);

Multiple documents can be retrieved by providing a collection of ids as follows:

Example 53. Realtime multi-get
Collection<String> ids = Arrays.asList("123", "134");
Collection<Product> products = solrTemplate.getById(ids, Product.class);

4.16. Special Fields

4.16.1. @Score

In order to load score information of a query result, a field annotated with @Score annotation could be added, indicating the property holding the documents score.

The score property needs to be numerical and can only appear once per document.
public class MyEntity {

    @Id
    private String id;

    @Score
    private Float score;

    // setters and getters ...

}

Appendix

Appendix A: Namespace reference

The <repositories /> Element

The <repositories /> element triggers the setup of the Spring Data repository infrastructure. The most important attribute is base-package, which defines the package to scan for Spring Data repository interfaces. See “XML configuration”. The following table describes the attributes of the <repositories /> element:

Table 4. Attributes
Name Description

base-package

Defines the package to be scanned for repository interfaces that extend *Repository (the actual interface is determined by the specific Spring Data module) in auto-detection mode. All packages below the configured package are scanned, too. Wildcards are allowed.

repository-impl-postfix

Defines the postfix to autodetect custom repository implementations. Classes whose names end with the configured postfix are considered as candidates. Defaults to Impl.

query-lookup-strategy

Determines the strategy to be used to create finder queries. See “Query Lookup Strategies” for details. Defaults to create-if-not-found.

named-queries-location

Defines the location to search for a Properties file containing externally defined queries.

consider-nested-repositories

Whether nested repository interface definitions should be considered. Defaults to false.

Appendix B: Populators namespace reference

The <populator /> element

The <populator /> element allows to populate the a data store via the Spring Data repository infrastructure.[1]

Table 5. Attributes
Name Description

locations

Where to find the files to read the objects from the repository shall be populated with.

Appendix C: Repository query keywords

Supported query keywords

The following table lists the keywords generally supported by the Spring Data repository query derivation mechanism. However, consult the store-specific documentation for the exact list of supported keywords, because some keywords listed here might not be supported in a particular store.

Table 6. Query keywords
Logical keyword Keyword expressions

AND

And

OR

Or

AFTER

After, IsAfter

BEFORE

Before, IsBefore

CONTAINING

Containing, IsContaining, Contains

BETWEEN

Between, IsBetween

ENDING_WITH

EndingWith, IsEndingWith, EndsWith

EXISTS

Exists

FALSE

False, IsFalse

GREATER_THAN

GreaterThan, IsGreaterThan

GREATER_THAN_EQUALS

GreaterThanEqual, IsGreaterThanEqual

IN

In, IsIn

IS

Is, Equals, (or no keyword)

IS_NOT_NULL

NotNull, IsNotNull

IS_NULL

Null, IsNull

LESS_THAN

LessThan, IsLessThan

LESS_THAN_EQUAL

LessThanEqual, IsLessThanEqual

LIKE

Like, IsLike

NEAR

Near, IsNear

NOT

Not, IsNot

NOT_IN

NotIn, IsNotIn

NOT_LIKE

NotLike, IsNotLike

REGEX

Regex, MatchesRegex, Matches

STARTING_WITH

StartingWith, IsStartingWith, StartsWith

TRUE

True, IsTrue

WITHIN

Within, IsWithin

Appendix D: Repository query return types

Supported Query Return Types

The following table lists the return types generally supported by Spring Data repositories. However, consult the store-specific documentation for the exact list of supported return types, because some types listed here might not be supported in a particular store.

Geospatial types (such as GeoResult, GeoResults, and GeoPage) are available only for data stores that support geospatial queries.
Table 7. Query return types
Return type Description

void

Denotes no return value.

Primitives

Java primitives.

Wrapper types

Java wrapper types.

T

An unique entity. Expects the query method to return one result at most. If no result is found, null is returned. More than one result triggers an IncorrectResultSizeDataAccessException.

Iterator<T>

An Iterator.

Collection<T>

A Collection.

List<T>

A List.

Optional<T>

A Java 8 or Guava Optional. Expects the query method to return one result at most. If no result is found, Optional.empty() or Optional.absent() is returned. More than one result triggers an IncorrectResultSizeDataAccessException.

Option<T>

Either a Scala or Javaslang Option type. Semantically the same behavior as Java 8’s Optional, described earlier.

Stream<T>

A Java 8 Stream.

Future<T>

A Future. Expects a method to be annotated with @Async and requires Spring’s asynchronous method execution capability to be enabled.

CompletableFuture<T>

A Java 8 CompletableFuture. Expects a method to be annotated with @Async and requires Spring’s asynchronous method execution capability to be enabled.

ListenableFuture

A org.springframework.util.concurrent.ListenableFuture. Expects a method to be annotated with @Async and requires Spring’s asynchronous method execution capability to be enabled.

Slice

A sized chunk of data with an indication of whether there is more data available. Requires a Pageable method parameter.

Page<T>

A Slice with additional information, such as the total number of results. Requires a Pageable method parameter.

GeoResult<T>

A result entry with additional information, such as the distance to a reference location.

GeoResults<T>

A list of GeoResult<T> with additional information, such as the average distance to a reference location.

GeoPage<T>

A Page with GeoResult<T>, such as the average distance to a reference location.

Mono<T>

A Project Reactor Mono emitting zero or one element using reactive repositories. Expects the query method to return one result at most. If no result is found, Mono.empty() is returned. More than one result triggers an IncorrectResultSizeDataAccessException.

Flux<T>

A Project Reactor Flux emitting zero, one, or many elements using reactive repositories. Queries returning Flux can emit also an infinite number of elements.

Single<T>

A RxJava Single emitting a single element using reactive repositories. Expects the query method to return one result at most. If no result is found, Mono.empty() is returned. More than one result triggers an IncorrectResultSizeDataAccessException.

Maybe<T>

A RxJava Maybe emitting zero or one element using reactive repositories. Expects the query method to return one result at most. If no result is found, Mono.empty() is returned. More than one result triggers an IncorrectResultSizeDataAccessException.

Flowable<T>

A RxJava Flowable emitting zero, one, or many elements using reactive repositories. Queries returning Flowable can emit also an infinite number of elements.


1. see XML configuration