Pull-Forward Data-Adapter are required if it is not possible (or not wanted) to build and deploy a plugin to the data provider that pushes data changes to a Push-Forward Data-Adapter. Therefore the main design idea is that this adapter pulls data from the data-provider on a regular basis.
Creating the Timer-EJB (adapter core)
Timer EJB
@Startup
@Singleton
public class PullForwardControllerBean {
@Schedule(second="*/30", minute="*",hour="*", persistent=false)
public void pullData(){
String eom = "";
String metricRef = "my.metric.identifier";
double value = 0.0;
// Get Data From remote location
List<Data> allData = getDataFromRemoteLocation();
for (Data data : allData) {
eom = data.getEom();
value = data.getValue();
try {
sender.sendMeasure(eom, metricRef, value, "");
// Logging for Monitoring
Long messageSize = 4;
monitoring.notifyEMDBMessageSend(BusType.Measures, metricRef, messageSize);
} catch (JMSException e) {
Logger.getLogger(EMDBMeasurementRestGatewayBean.class.getName()).severe(e.getMessage());
logError(e);
} catch (JAXBException e) {
Logger.getLogger(EMDBMeasurementRestGatewayBean.class.getName()).severe(e.getMessage());
logError(e);
}
}
}
}
This pulls data from a remote data provider every 30 seconds.
