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
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esper:name[?options] |
When consuming from an Esper endpoint you must specify a pattern or eql statement to query the event stream.
Pattern example:
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from("esper://cheese?pattern=every event=MyEvent(bar=5)") .to("activemq:Foo"); |
EQL example:
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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
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{div:class=confluenceTableSmall} || Name || Default Value || Description || | {{configured}} | false | Available as of camel-extra 2.11.3: If flag is set to 'true' the default Esper configuration file (esper.cfg.xml) will be used. To configure Esper via a configuration file, please refer to the [Esper documentation|http://esper.codehaus.org/esper-4.2.0/doc/reference/en/html/configuration.html] | | {{pattern}} | | The [Esper Pattern 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-4.10.0/doc/reference/en-US/html/epl_clauses.html] as a String to filter events | {div} |
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:
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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
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