Esper is an open-source Java-based software product for complex event processing (CEP) and event stream processing (ESP), that analyzes series of events for deriving conclusions from them.
Esper extends the SQL-92 standard for its engine and enterprise framework, providing Aggregate function, Pattern matching, event windowing and joining. Esper implements Event-driven programming and event-driven architecture.
Esper was created in 2006 by EsperTech Inc. It offers a Domain-specific language for processing events called Event Processing Language (EPL). EPL is a Declarative programming language for analyzing time-based event data and detecting situations as they occur.
Esper is a Java-based application but has been ported to the C# programming language and is available for the .NET Framework under the name NEsper.
Example This example illustrates a simple EPL query that outputs a row immediately when within a sliding window of 3 minutes the number of order events reaches 5 or more events.
select count(*) from OrderEvent#time(3 min) having count(*) >= 5
Related systems Rapide (Stanford) StreamSQL: StreamSQL is a query language that extends SQL with the ability to process real-time data streams.
See also
Complex event processing (CEP) - A related technology for building and managing event-driven information systems. Data Stream Management System (DSMS) - A type of software system for managing and querying data streams Event correlation Event-driven architecture — (EDA) is a software architecture pattern promoting the production, detection, consumption of, and reaction to events. Event stream processing — (ESP) is a related technology that focuses on processing streams of related data. Operational intelligence — Both CEP and ESP are technologies that underpin operational intelligence. Pattern matching Real-time business intelligence — Business Intelligence is the application of knowledge derived from CEP systems Real-time computing — CEP systems are typically real-time systems Real time enterprise
References
External links Research Papers referencing Esper, by Google Scholar Analysis of Complex Event Processing with Esper by Eric Miller, a book on Esper and CEP. Event Processing in Action by Opher Etzion and Peter Niblett, Manning Publications (), a book that provides Esper examples Open Source SOA by Jeff Davis, Manning Publications (), a book that provides examples of Esper for monitoring web services OSWorkflow: A guide for Java developers and architects to integrating open-source Business Process Management, by Diego Adrian Naya Lazo, PACKT ( ), a book with a chapter on Esper Fraunhofer CEP Market Overview, by Fraunhofer, year 2010