Example brooklyn groovy code to poll an underlying resource, to update attributes (aka sensors)

gistfile1.java

// Polls a given URL, and uses the HTTP response to set the 
// two Brooklyn entity attributes SERVICE_UP and REQUEST_COUNT

    def http = sensorRegistry.register(
            new HttpSensorAdapter("http://$host:$port/management/subsystem/web/connector/http/read-resource",
                period: 200*TimeUnit.MILLISECONDS).
                vars("include-runtime":true) )
       
    with(http) {
        poll(SERVICE_UP) { responseCode==200 }
        poll(REQUEST_COUNT) { json.requestCount }
        // etc
    }

// Subscribes to JMX attribute-change events for given attributes on an given MBean, 
// to set the Brooklyn entity attributes ERROR_COUNT and REQUEST_COUNT

    JmxSensorAdapter jmx = sensorRegistry.register(new JmxSensorAdapter(period: 500*TimeUnit.MILLISECONDS));

    jmx.objectName("jboss.web:type=GlobalRequestProcessor,name=http-*").with {
        attribute("errorCount").subscribe(ERROR_COUNT)
        attribute("requestCount").subscribe(REQUEST_COUNT)
        // etc
    }