Eventsourcing for Java

Instead of mutating data in a database, it stores all changes (events) and causes (commands). This facilitates rapid application development and evolution by mitigating the inability to predict how future needs will drive data shape requirements as all causal information is persisted. It also provides a foundation for deep analytics, data recovery, audit trails and other associated benefits.

This is an early version. That said, it's a rewrite of another library that has been used in real projects, so a lot was learned and incorporated in this incarnation.

Key benefits

Flexibility of data aggregation and representation
Persistence of causal information
Succinctly mapped application functionality
Undo/redo functionality
Audit trail logging

Key features

Clean, succinct Command/Event model
Compact data storage layout
Using Disruptor for fast message processing
Using CQengine for fast indexing and querying
In-memory and on-disk (more persistent indices coming soon) storage
Causality-preserving Hybrid Logical Clocks
Locking synchronization primitive

Documentation

Installation instructions and documentation can be found at es4j-doc.eventsourcing.com

Related projects

es4j-graphql A Relay.js/GraphQL adaptor for ES4J-based applications.

Contributing

Contributions of all kinds (code, documentation, testing, artwork, etc.) are highly encouraged. Please open a GitHub issue if you want to suggest an idea or ask a question.