Esper

Esper

The Esper component supports the Esper Library for Event Stream Processing. The camel-esper library is provided by the Camel Extra project which hosts all *GPL related components for Apache Camel.

URI format

esper:name[?options]

When consuming from an Esper endpoint you must specify a pattern or eql statement to query the event stream.

For example

from("esper://cheese?pattern=every event=MyEvent(bar=5)").
	to("activemq:Foo");

You can append query options to the URI in the following format, ?option=value&option=value&...

Options

Name Default Value Description
pattern The Esper Pattern expression as a String to filter events
eql The Esper EQL expression as a String to filter events

EsperMessage

From Camel 2.12 onwards the esper consumer stores new and old events in the org.apacheextras.camel.component.esper.EsperMessage message as the input Message on the Exchange. You can get access to the esper event beans from java code with:

EventBean newEvent = exchange.getIn(EsperMessage.class).getNewEvent();
EventBean oldEvent = exchange.getIn(EsperMessage.class).getOldEvent();

By default if you get the body of org.apacheextras.camel.component.esper.EsperMessage it returns the new EventBean as in previous versions.

Demo

There is a demo which shows how to work with ActiveMQ, Apache Camel, and Esper in the Camel Extra project