1. Apache flink - stateful computations over data streams. https://flink.apache.org/
2. Apache kafka. https://kafka.apache.org/
3. Esper. http://www.espertech.com/esper
4. Esperonstorm. https://github.com/tomdz/storm-esper
5. Flinkcep - complex event processing for flink. https://ci.apache.org/projects/flink/flink-docs-stable/dev/libs/cep.html