Datastax Java Driver for Apache Cassandra

If you're reading this on github.com, please note that this is the readme for the development version and that some features described here might not yet have been released. You can find the documentation for latest version through Java driver docs or via the release tags, e.g. 3.1.0.

A modern, feature-rich and highly tunable Java client library for Apache Cassandra (1.2+) and DataStax Enterprise (3.1+) using exclusively Cassandra's binary protocol and Cassandra Query Language v3.

Features:

• Sync and Async API
• Simple, Prepared, and Batch statements
• Asynchronous IO, parallel execution, request pipelining
• Connection pooling
• Auto node discovery
• Automatic reconnection
• Configurable load balancing and retry policies
• Works with any cluster size
• Query builder
• Object mapper

The driver architecture is based on layers. At the bottom lies the driver core. This core handles everything related to the connections to a Cassandra cluster (for example, connection pool, discovering new nodes, etc.) and exposes a simple, relatively low-level API on top of which higher level layers can be built.

The driver contains the following modules:

• driver-core: the core layer.
• driver-mapping: the object mapper.
• driver-extras: optional features for the Java driver.
• driver-examples: example applications using the other modules which are only meant for demonstration purposes.
• driver-tests: tests for the java-driver.

Useful links:

• JIRA (bug tracking): https://datastax-oss.atlassian.net/browse/JAVA
• MAILING LIST: https://groups.google.com/a/lists.datastax.com/forum/#!forum/java-driver-user
• IRC: #datastax-drivers on irc.freenode.net
• TWITTER: @dsJavaDriver tweets Java driver releases and important announcements (low frequency). @DataStaxEng has more news including other drivers, Cassandra, and DSE.
• DOCS: the user guide has introductory material. We are progressively migrating the doc here with more technical details.
• API: http://www.datastax.com/drivers/java/3.0
• changelog
• binary tarball

Feeback requested: help us focus our efforts, provide your input on the Platform and Runtime Survey (we kept it short).

Getting the driver

The last release of the driver is available on Maven Central. You can install it in your application using the following Maven dependency:

<dependency>
  <groupId>com.datastax.cassandra</groupId>
  <artifactId>cassandra-driver-core</artifactId>
  <version>3.1.0</version>
</dependency>

Note that the object mapper is published as a separate artifact:

<dependency>
  <groupId>com.datastax.cassandra</groupId>
  <artifactId>cassandra-driver-mapping</artifactId>
  <version>3.1.0</version>
</dependency>

The 'extras' module is also published as a separate artifact:

<dependency>
  <groupId>com.datastax.cassandra</groupId>
  <artifactId>cassandra-driver-extras</artifactId>
  <version>3.1.0</version>
</dependency>

We also provide a shaded JAR to avoid the explicit dependency to Netty.

If you can't use a dependency management tool, a binary tarball is available for download.

Compatibility

The Java client driver 3.1.0 (branch 3.0) is compatible with Apache Cassandra 1.2, 2.0, 2.1, 2.2 and 3.0 (see this page for the most up-to-date compatibility information).

UDT and tuple support is available only when using Apache Cassandra 2.1 or higher (see CQL improvements in Cassandra 2.1).

Other features are available only when using Apache Cassandra 2.0 or higher (e.g. result set paging, BatchStatement, lightweight transactions -- see What's new in Cassandra 2.0). Trying to use these with a cluster running Cassandra 1.2 will result in an UnsupportedFeatureException being thrown.

Upgrading from previous versions

If you are upgrading from a previous version of the driver, be sure to have a look at the upgrade guide.

Troubleshooting

If you are having issues connecting to the cluster (seeing NoHostAvailableConnection exceptions) please check the connection requirements.

License

Copyright 2012-2015, DataStax

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.