[CONF] Apache Camel > Esper

[Christoph Emmersberger (Confluence)]

Esper Page edited by Christoph Emmersberger Comment: adding an eql example Changes (9) ... When consuming from an Esper endpoint you must specify a *pattern* or *eql* statement to query the event stream. For example Pattern example: {code} from("esper://cheese?pattern=every event=MyEvent(bar=5)") .to("activemq:Foo"); {code} EQL example: {code} from("esper://cheese?pattern=every event=MyEvent(bar=5)"). from("esper://esper-dom?eql=insert into DomStream select * from org.w3c.dom.Document") to("activemq:Foo"); .to("log://esper-dom?level=INFO"); from("esper://esper-dom?eql=select childNodes from DomStream") .to("mock:results"); {code} ... {div:class=confluenceTableSmall} || Name || Default Value || Description || | {{pattern}} | | The [Esper Pattern _expression_|http://esper.codehaus.org/esper-1.11.0/doc/reference/en/html/event_patterns.html] _expression_|http://esper.codehaus.org/esper-4.10.0/doc/reference/en-US/html/event_patterns.html] as a String to filter events | | {{eql}} | | The [Esper EQL _expression_|http://esper.codehaus.org/esper-1.11.0/doc/reference/en/html/eql_clauses.html] _expression_|http://esper.codehaus.org/esper-4.10.0/doc/reference/en-US/html/epl_clauses.html] as a String to filter events | {div} ... {code} EventBean newEvent = exchange.getIn(EsperMessage.class).getNewEvent(); EventBean oldEvent = exchange.getIn(EsperMessage.class).getOldEvent(); {code} ... Full Content 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 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. Pattern example: from("esper://cheese?pattern=every event=MyEvent(bar=5)") .to("activemq:Foo"); EQL example: from("esper://esper-dom?eql=insert into DomStream select * from org.w3c.dom.Document") .to("log://esper-dom?level=INFO"); from("esper://esper-dom?eql=select childNodes from DomStream") .to("mock:results"); 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 You can append query options to the URI in the following format, ?option=value&option=value&... 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, Camel and Esper in the Camel Extra project See Also Configuring Camel Component Endpoint Getting Started Esper Camel Demo Stop watching space | Change email notification preferences View Online | View Changes