NoSchema

NoSchema is a Java library for storing domain objects in Cassandra using a document-oriented repository pattern. It writes entity payloads as serialized blobs while extracting identifier components into Cassandra key columns, allowing denormalized access patterns without manual materialized-view maintenance.

Highlights

• PrimaryTable, View, and Index definitions via DSLs.
• Automatic fan-out writes across primary/view/index tables through UnitOfWork.
• Pluggable serialization with DocumentCodec<T>.
• Built-in codecs: JacksonObjectCodec and GsonObjectCodec.
• Lifecycle hooks at both document and entity layers:
  • DocumentObserver (AbstractDocumentObserver, GzipDocumentObserver)
  • RepositoryObserver<T>

Modules

1. core: shared interfaces and contracts (Repository, Identifiable, Identifier, DocumentCodec, exceptions, unit-of-work abstractions).
2. cassandra: Cassandra repository implementation (CassandraRepository), table/key DSLs, schema providers, and Cassandra-specific unit-of-work strategies.
3. jackson-provider: Jackson implementation of DocumentCodec.
4. gson-provider: Gson implementation of DocumentCodec.

Requirements

• Java 21
• Maven 3.8+
• Cassandra cluster reachable by your application

Maven Dependencies

Jackson setup:

<dependency>
	<groupId>com.strategicgains.noschema</groupId>
	<artifactId>noschema-cassandra</artifactId>
	<version>1.0.0-SNAPSHOT</version>
</dependency>
<dependency>
	<groupId>com.strategicgains.noschema</groupId>
	<artifactId>noschema-jackson-provider</artifactId>
	<version>1.0.0-SNAPSHOT</version>
</dependency>

Gson setup:

<dependency>
	<groupId>com.strategicgains.noschema</groupId>
	<artifactId>noschema-cassandra</artifactId>
	<version>1.0.0-SNAPSHOT</version>
</dependency>
<dependency>
	<groupId>com.strategicgains.noschema</groupId>
	<artifactId>noschema-gson-provider</artifactId>
	<version>1.0.0-SNAPSHOT</version>
</dependency>

Quick Start

Entities must implement Identifiable by returning an Identifier from getIdentifier().

Define a repository by extending CassandraRepository<T>:

public class AlbumRepository extends CassandraRepository<Album>
{
	private static final String BY_NAME = "by_name";

	public AlbumRepository(CqlSession session, String keyspace, DocumentCodec<Album> codec)
	throws KeyDefinitionException
	{
		super(session,
			new PrimaryTable(keyspace, "albums", "id:uuid unique")
				.withView(BY_NAME, "(account.id as account_id:uuid), name:text unique"),
			UnitOfWorkType.ASYNC,
			codec
		);
	}

	public Album readById(UUID id)
	{
		return read(new Identifier(id));
	}

	public Album readByName(UUID accountId, String name)
	{
		return read(BY_NAME, new Identifier(accountId, name));
	}
}

Use the repository:

DocumentCodec<Album> codec = new JacksonObjectCodec<>();
AlbumRepository albums = new AlbumRepository(session, "sample_keyspace", codec);
albums.withDocumentObserver(new GzipDocumentObserver());

albums.ensureTables();
Album created = albums.create(album);
Album byId = albums.read(new Identifier(created.getId()));

Key Definition DSL

Key strings support partition keys, clustering keys, property-to-column mapping, and uniqueness:

id:uuid unique
(account.id as account_id:uuid), name:text unique
((account.id as account_id:uuid), -created_at:timestamp)

General grammar:

key-definition ::= "(" partition-key ")" clustering-key modifier
partition-key ::= column-definition | column-definition "," column-definition
clustering-key ::= clustering-key-component | clustering-key "," clustering-key-component
modifier ::= "unique" | ε
clustering-key-component ::= "+" column-definition | "-" column-definition | column-definition
column-definition ::= name-type-pair | property-name " as " name-type-pair
name-type-pair ::= name ":" type
property-name ::= [a-zA-Z0-9_]+

Build and Test

• mvn clean verify: full build with tests and source/javadoc artifacts.
• mvn test: run all tests.
• mvn -pl cassandra -Dtest=KeyDefinitionParserTest test: run one test class.

Contributing

Submit pull requests with focused, module-scoped changes, a clear rationale, and test commands used.

License

NoSchema is licensed under Apache License 2.0.