Spring Data Couchbase 2.0.x

Spring-Data Couchbase 2.0.x is the Spring Data connector for the Couchbase Java SDK 2.x generation.

Both the SDK and this Spring Data community project are major version changes with lots of differences from their respective previous versions.

Notably, this version is compatible with Couchbase Server 4.0, bringing support for the N1QL query language.

Spring Data Couchbase

The primary goal of the Spring Data project is to make it easier to build Spring-powered applications that use new data access technologies such as non-relational databases, map-reduce frameworks, and cloud based data services.

The Spring Data Couchbase project aims to provide a familiar and consistent Spring-based programming model for Couchbase Server as a document database and cache while retaining store-specific features and capabilities. Key functional areas of Spring Data Couchbase are a POJO centric model for interacting with a Couchbase Server Bucket and easily writing a repository style data access layer.

Getting Help

For a comprehensive treatment of all the Spring Data Couchbase features, please refer to:

• the User Guide for the current GA version.
• the JavaDocs have extensive comments in them as well.
• for more detailed questions, use the StackOverflow spring-data-couchbase tag or Couchbase's own forums.

If you are new to Spring as well as to Spring Data, look for information about Spring projects.

Quick Start

Maven configuration

Add the Maven dependency:

<dependency>
  <groupId>org.springframework.data</groupId>
  <artifactId>spring-data-couchbase</artifactId>
  <version>2.0.0.RELEASE</version>
</dependency>

If you'd rather like the latest snapshots of the upcoming major version, use our Maven snapshot repository and declare the appropriate dependency version.

<dependency>
  <groupId>org.springframework.data</groupId>
  <artifactId>spring-data-couchbase</artifactId>
  <version>2.1.0.BUILD-SNAPSHOT</version>
</dependency>

<repository>
  <id>spring-libs-snapshot</id>
  <name>Spring Snapshot Repository</name>
  <url>http://repo.spring.io/libs-snapshot</url>
</repository>

CouchbaseTemplate

CouchbaseTemplate is the central support class for Couchbase database operations. It provides:

• Basic POJO mapping support to and from JSON (by default through Jackson)
• Convenience methods to interact with the store (insert object, update objects) and Couchbase specific ones
• Exception translation into Spring's technology agnostic DAO exception hierarchy.

Spring Data Repositories

To simplify the creation of data repositories Spring Data Couchbase provides a generic repository programming model. It will automatically create a repository proxy for you that adds implementations of finder methods you specify on an interface.

To create a repository on top of a UserInfo entity, all you need to write is:

public interface UserRepository extends CrudRepository<UserInfo, String> {

  /**
   * Return all users emitted by the view userInfo/adults
   */
  @View
  List<UserInfo> findAdults();
  
  /**
   * Find all users matching the last name.
   */
  @View(viewName="lastNames")     
  List<UserInfo> findByLastname(String lastName);
  
  /**
   * Find all the users whose first name contains the word.
   */
  List<UserInfo> findByFirstnameContains(String word);

}

Once you get a reference to that repository bean, you'll find a lot of methods that make it very easy to work with this entity. In addition to the ones provided through the CrudRepository, you can add your own methods as well.

In general, every CRUD method that does not depend on a single key (like findById) needs a backing View, all on the server side (the design document is by default expected to be the uncapitalized name of the entity, like userInfo).

Custom Repository Methods and Views

Finder methods you define, if annotated with @View, also are backed by views. Either you want to return all items from these views and you can let the method name reflect the view name (like in findAdults(), where it'll expect an adults view), or provide simple criteria (you explicitly specify the viewName and let the method name determine your criteria, like in findByLastname).

In the example above, it assumes you have a view named findByLastname in the userInfo design document. You can customize the view and design document name through the @View annotation. Also make sure you publish them into production before accessing it.

This is an example view for the findByLastname method:

function (doc, meta) {
  if(doc._class == "com.example.entity.UserInfo" && doc.lastname) {
    emit(doc.lastname, null);
  }
}

If you want to use more query parameters than what is supported through query derivation (see ViewQueryCreator), you need to provide the implementation of the finder methods yourself and use the underlying CouchbaseTemplate.

The all view that backs CRUD findAll() and count() needs to look like this (and do not forget the _count reduce function):

function (doc, meta) {
  if(doc._class == "com.example.entity.UserInfo") {
    emit(null, null);
  }
}

Alternatively, if view creation isn't too costly, you can ask the framework to create it automatically by annotating the repository with @ViewIndexed(designDoc = "userInfo", viewName = "all").

N1QL and Query Derivation

With the introduction of N1QL, Couchbase can now better support query derivation (the mechanism that allows you to add custom methods that will automatically be implemented as a N1QL query derived from the method's name).

This is the default repository query mechanism, so the associated @Query annotation is optional. Here is what it looks like:

public interface UserRepository extends CrudRepository<UserInfo, String> {

  /**
   * Advanced querying with N1QL derivation
   */
  @Query
  List<UserInfo> findByLastnameEqualsIgnoreCaseAndFirstnameStartsWithAndIsAdultTrue(String lastName, String fnamePrefix);
}

For instance, calling find...("Locke", "J") will get resolved to this N1QL WHERE clause (similar to SQL):

...WHERE LOWER(lastname) = LOWER("Locke") AND firstname LIKE "J%" AND isAdult = TRUE;

You can alternatively write the statement yourself inside the @Query annotation, using the $SELECT_ENTITY$ placeholder to make sure all necessary fields and metadata are selected by N1QL:

@Query("$SELECT_ENTITY$ WHERE firstname LIKE "%ck%")
List<UserInfo> findPatrickAndJackAmongOthers();

@Query("$SELECT_ENTITY$ WHERE firstname LIKE $1")
List<UserInfo> findUsersWithTheirFirstnameLike(String likePattern);

N1QL needs at least a generic purpose N1QL primary index to work with, and can make use of a more entity type-specific N1QL secondary index. You can create both automatically (provided you are confident this is not to much of a cost) by annotating a repository with @N1qlPrimaryIndexed and/or @N1qlSecondaryIndexed.

Using The Repository

Extending CrudRepository causes CRUD methods being pulled into the interface so that you can easily save and find single entities and collections of them.

You can have Spring automatically create a proxy for the interface by using the following JavaConfig:

@Configuration
@EnableCouchbaseRepositories
public class Config extends AbstractCouchbaseConfiguration {

	@Override
	protected List<String> getBootstrapHosts() {
		return Arrays.asList("host1", "host2");
	}

	@Override
	protected String getBucketName() {
		return "default";
	}

	@Override
	protected String getBucketPassword() {
		return "";
	}
}

This sets up a connection to a Couchbase cluster and enables the detection of Spring Data repositories (through @EnableCouchbaseRepositories). The same configuration would look like this in XML:

<couchbase:cluster id="cb-first">
  <couchbase:node>localhost</couchbase:node>
</couchbase:cluster>

<couchbase:bucket id="cb-bucket-first" cluster-ref="cb-first" bucket="default" password="" />

<couchbase:template id="cb-template-first"  bucket-ref="cb-bucket-first" />

<couchbase:repositories couchbase-template-ref="cb-template-first" />

This will find the repository interface and register a proxy object in the container. You can use it as shown below:

@Service
public class MyService {

  private final UserRepository userRepository;

    @Autowired
  public MyService(UserRepository userRepository) {
    this.userRepository = userRepository;
  }

  public void doWork() {
    userRepository.deleteAll();

    UserInfo userInfo = new UserInfo();
    UserInfo.setLastname("Jackson");

    UserInfo = userRepository.save(userInfo);

    List<UserInfo> allJacksons = userRepository.findByLastname("Jackson");
  }
}

Contributing to Spring Data

Here are some ways for you to get involved in the community:

• Get involved with the Spring community on Stack Overflow. Please help out on the spring-data and spring-data-couchbase tags by responding to questions.
• Create JIRA DATACOUCH tickets for bugs and new features and comment and vote on the ones that you are interested in.
• Github is for social coding: if you want to write code, we encourage contributions through pull requests from forks of this repository. If you want to contribute code this way, please reference a JIRA ticket as well covering the specific issue you are addressing.
• Watch for upcoming articles on Spring by subscribing to spring.io RSS feed.

BBefore we accept a non-trivial patch or pull request we will need you to sign the Contributor License Agreement. Signing the contributor’s agreement does not grant anyone commit rights to the main repository, but it does mean that we can accept your contributions, and you will get an author credit if we do. If you forget to do so, you'll be reminded when you submit a pull request. Active contributors might be asked to join the core team, and given the ability to merge pull requests.