Java CRDT Library

A collection of basic conflict-free replicated data types (CRDTs). Currently everything is set up to serialize into JSON objects.

Goals

• Provide a set of common interfaces, patterns, and objects for working with CRDTs.
• Some degree of storage independence. The emphasis is on Riak, but the objects should be portable.

Features

• Support for GSets, 2PSets, ORSets, GCounters, PNCounters.
• Unified interfaces for serialization/deserialization of CRDT objects.
• JSON serialization.
• JSR 330 annotations for dependency injection.
• JSR 305 annotations for documenting proper use of the API and documenting thread safety.

Future Work

Roughly in order:

• Better Jackson use and integration.
• Removing the self-serialization aspects (or at least make them optional) to better integrate with available tools for working with annotated objects. There are some challenges here that I am trying to find a clean solution for.
• Tools for specifically working with Riak.
• Integration tests.
• Full, eventual transition to Java 7.
• Some form of versioning for (de)serialization purposes.
• Have the counters support other Number types.
• Guice modules with the bindings for convenience.
• Derived types for collecting more specific types of information (e.g., statistics).
• More basic types (e.g., graphs, LWW).
• Add garbage collection.
• Support for other serialization methods.
• Local caching of immutable views.

Based On

• Conflict Free Replicated Data Types
• A comprehensive study of Convergent and Commutative Replicated Data Types
• An Optimized Conflict-free Replicated Set
• @ericmortiz's CRDT Library in Python