lynchlee / spring-data-cassandra

Provides support to increase developer productivity in Java when using Cassandra. Uses familiar Spring concepts such as a template classes for core API usage and lightweight repository style data access.

Spring Data Cassandra Project Info

Quick Start

To begin working with spring-cql or spring-data-cassandra, add the Spring Maven Snapshot Repository to your pom.xml.

Releases

Generally available releases are available in Maven Central.

Snapshots

<repository>
	<id>spring-libs-snapshot</id>
	<url>http://repo.spring.io/libs-snapshot</url>
	<snapshots>
		<enabled>true</enabled>
	</snapshots>
</repository>

Raw CQL only with no POJO mapping (spring-cql)

Maven Coordinates

<dependency>
	<groupId>org.springframework.data</groupId>
	<artifactId>spring-cql</artifactId>
	<version>${version}.RELEASE</version>
</dependency>

Minimal Spring XML Configuration

<cql:cluster />
<cql:session keyspace-name="sensors" />
<cql:template />

Minimal Spring JavaConfig

@Configuration
public class MyConfig extends AbstractSessionConfiguration {
	
	@Override
	public String getKeyspaceName() {
		return "sensors";
	}
	
	@Bean
	public CqlOperations cqlTemplate() {
		return new CqlTemplate(session.getObject());
	}
}

Application Class

public class SensorService {
	
	@Autowired
	CqlOperations template;
	
	// ...
}

CQL and POJO mapping (spring-data-cassandra)

Maven Coordinates

<dependency>
	<groupId>org.springframework.data</groupId>
	<artifactId>spring-data-cassandra</artifactId>
	<version>${version}.RELEASE</version>
</dependency>

Minimal Spring XML Configuration

<cassandra:cluster />
<cassandra:session keyspace-name="foobar" />
<cassandra:repositories base-package="org.example.domain" />

Minimal Spring JavaConfig

@Configuration
@EnableCassandraRepositories(basePackages = "org.example.domain")
public class MyConfig extends AbstractCassandraConfiguration {
	
	@Override
	public String getKeyspaceName() {
		return "foobar";
	}
}

Application Class

public class SensorService {
	
	@Autowired
	SensorRepository repo;
	
	// ...
}

What's included

There are two modules included in the spring-data-cassandra repository: spring-cql and spring-data-cassandra.

Module spring-cql: Pure CQL support a la Spring's template pattern

This is the low-level core template framework, like the ones you are used to using on all your Spring projects. Our CqlTemplate provides everything you need for working with Cassandra using Spring's familiar template pattern in a manner very similar to Spring's JdbcTemplate.

This includes persistence exception translation, Spring JavaConfig and XML configuration support. Define your Spring beans to setup your Cassandra Cluster object, then create your Session and you are ready to interact with Cassandra using the CqlTemplate.

The module also offers convenient builder pattern classes to easily specify the creation, alteration, and dropping of keyspaces via a fluent API. They are intended to be used with generators that produce CQL that can then be easily executed by CqlTemplate. See test class CreateTableCqlGeneratorTests for examples. Don't forget to check out class MapBuilder for easy creation of Cassandra TableOption values. The builders & CQL generators for CREATE TABLE, ALTER TABLE, and DROP TABLE operations are

• CreateTableSpecification & CreateTableCqlGenerator,
• AlterTableSpecification & AlterTableCqlGenerator, and
• DropTableSpecification & DropTableCqlGenerator, respectively.

The support for Spring JavaConfig and a Spring Cassandra XML namespace makes it easy to configure your context to work with Cassandra, including XML namespace support for automatic keyspace creations, drops & more, which can be convenient when writing integration tests.

Module spring-data-cassandra: Spring Data POJO persistence over Cassandra

The spring-data-cassandra module depends on the spring-cql module and adds the familiar Spring Data features like repositories and lightweight POJO persistence.

Best practices

We have worked closely with the DataStax Driver Engineering team to ensure that our implementation around their native CQL Driver takes advantage of all that it has to offer. If you need access to more than one keyspace in your application, create more than one CqlTemplate (one CqlTemplate per session, one session per keyspace), then use the appropriate template instance where needed.

Here are some considerations when designing your application for use with spring-cql (as well as spring-data-cassandra).

• When creating a template, wire in a single Session per keyspace.
• Session is threadsafe, so only use one per keyspace per application context!
• Do not issue USE <keyspace> commands on your session; instead, configure the keyspace name you intend to use.
• The DataStax Java Driver handles all failover and retry logic for you. Become familiar with the Driver Documentation, which will help you configure your Cluster.
• If you are using a Cassandra Cluster spanning multiple data centers, please be insure to include hosts from all data centers in your contact points.

High Performance Ingestion

We have included a variety of overloaded ingest(..) methods in CqlTemplate for high performance batch writes.

CassandraRepository

The base Spring Data Repository interface for Cassandra is CassandraRepository. This allows you to simply annotate key fields directly in your entity instead of having to define your own primary key classes, although you still can (see the parent interface of CassandraRepository, called TypedIdCassandraRepository<T,ID>). In fact, CassandraRepository uses a provided primary key class called MapId, and declares itself to extend TypedIdCassandraRepository<T, MapId>!

CassandraTemplate

CassandraTemplate extends CqlTemplate, adding mapping information so you can work with Cassandra using annotated POJOs. The Spring Data CassandraRepository implementation also happens to be a client of CassandraTemplate so, if necessary, a developer can work with annotated POJOs and the template pattern without ever using CassandraRepository.

CassandraAdminTemplate

This is another Spring template class to help you with your keyspace and table administration tasks.

CqlTemplate Examples

JavaConfig

Here is a very basic example to get your project connected to Cassandra running on your local machine.

@Configuration
public class TestConfig extends AbstractCassandraConfiguration {

	public static final String KEYSPACE = "test";

	@Override
	protected String getKeyspaceName() {
		return KEYSPACE;
	}

	@Bean
	public CqlOperations CqlTemplate() {
		return new CqlTemplate(session().getObject());
	}
}

XML Configuration

<cassandra-cluster />
<cassandra-session keyspace-name="test" />
<cassandra-template />

Using CqlTemplate

public class CqlOperationsTest {

	@Autowired
	private CqlOperations template;
	
	public Integer getCount() throws DataAccessException {
	
		String cql = "select count(*) from table_name where id='12345'";
		
		Integer count = template.queryForObject(cql, Integer.class);
		
		log.info("Row Count is -> " + count);
		
		return count;
	}
}

Source Repository & Issue Tracking

Source for this module is hosted on GitHub in Spring Projects.
The Spring Data Cassandra JIRA can be found here.

Reporting Problems

If you encounter a problem using this module, please report the issue to us using JIRA. Please provide as much information as you can, including:

• Cassandra version
• Community or DataStax distribution of Cassandra
• JDK Version
• Output of show schema where applicable
• Any stacktraces showing the location of the problem
• Steps to reproduce
• Any other relevant information that you would like to see if you were diagnosing the problem.

Please do not post anything to Jira or the mailing list on how to use Cassandra. That is beyond the scope of this module and there are a variety of resources available targeting that specific subject.

We recommend reading the following:

• PlanetCassandra.org
• Getting Started
• Driver Documentation

Contact

For more information, feel free to contact the individuals listed below:

• David Webb: dwebb at prowaveconsulting dot com
• Matthew Adams: matthew dot adams at scispike dot com

Also, developer discussions are being hosted on StackOverflow using the tag spring-data-cassandra.

Contributing Individuals

• David Webb
• Matthew Adams
• John McPeek

Sponsoring Companies

Spring Data Cassandra is being led and supported by the following companies and individuals:

• Prowave Consulting - David Webb
• SciSpike - Matthew Adams

The following companies and individuals are also generously providing support:

• DataStax
• Spring @ Pivotal
• Docbook Editor provided by Oxygen XML