The Java DataStax Driver comes with an object mapper that removes boilerplate of writing queries and lets you focus on your application objects. Java Records are shallowly immutable, transparent carriers for a fixed set of values. This example shows how to use the two together.
Note: records are a preview feature of Java 14. As such the mapper's support for them is also provided as a preview.
Contributor(s): Olivier Michallat
- Demonstrate how to map Java records as immutable entities.
There is a single source file: MapperApp. For concision, we define the mapped types (entity, DAO and mapper) as nested types, but they could equally be top-level types.
Unlike other mapper examples, the model is very simple: there is only a single table. Our goal is to show the specifics of Java records integration, not demonstrate every mapper feature (see the original Java example for a more complete scenario).
Sources must be compiled using Java 14 with the --enable-preview flag. See the compiler plugin
configuration in pom.xml.
For additional information and details on how to use the Mapper classes please refer to the documentation available here.
- JDK 14
- Java driver 4.9 or above (configured in pom.xml)
- A Cassandra cluster is running and accessible through the contacts points and data center identified in application.conf
At the project root level:
mvn clean package
This builds the JAR file located at target/object-mapper-record-1.0.jar
To run this application, use the following command:
java --enable-preview -jar target/object-mapper-record-1.0.jar
Note that, like for compilation, you also need to pass the --enable-preview flag when you start
the VM.
This will produce results similar to those below.
Saving Product[id=1, description=test]...
Retrieved Product[id=1, description=test]