Apama 10.3.1 | Apama Documentation | Connecting Apama Applications to External Components | Standard Connectivity Plug-ins | The Cumulocity IoT Transport Connectivity Plug-in | Using measurements | Querying for measurements
 
Querying for measurements
To search for a measurement or a collection of measurements, send the com.apama.cumulocity.FindMeasurement event to Cumulocity IoT, with a unique reqId to the com.apama.cumulocity.FindMeasurement.CHANNEL channel.
The transport will then respond with zero or more com.apama.cumulocity.FindMeasurementResponse events and then one com.apama.cumulocity.FindMeasurementResponseAck event on the com.apama.cumulocity.FindMeasurementResponse.CHANNEL channel.
Example:
integer reqId := integer.incrementCounter("CumulocityRequestId");
 
com.apama.cumulocity.FindMeasurement request :=
new com.apama.cumulocity.FindMeasurement;
request.reqId := reqId;
 
// Filter based on measurement fragmentType
request.params.add("fragmentType", "c8y_MotionMeasurement");
 
// Subscribe to com.apama.cumulocity.FindMeasurementResponse.CHANNEL to listen
// for responses
monitor.subscribe(com.apama.cumulocity.FindMeasurementResponse.CHANNEL);
 
// Listen for responses based on reqId
on all com.apama.cumulocity.FindMeasurementResponse(reqId=reqId) as response
// Avoid listener leaks by terminating the listener on completion of the request
and not com.apama.cumulocity.FindMeasurementResponseAck(reqId=reqId)
{
log "Received Measurement " + response.toString() at INFO;
}
 
// Listen for com.apama.cumulocity.FindMeasurementResponseAck,
// this indicates that all responses have been received
on com.apama.cumulocity.FindMeasurementResponseAck(reqId=reqId)
as requestCompleted
{
log "Received all Measurement(s) for request "
+ requestCompleted.reqId.toString() at INFO;
 
// Request is completed and we can unsubscribe from this channel
monitor.unsubscribe(com.apama.cumulocity.FindMeasurementResponse.CHANNEL);
}
 
// Send request to find available measurements
send request to com.apama.cumulocity.FindMeasurement.CHANNEL;
Supported query parameters
You can provide the following query parameters with the request:
Parameter
Description
id
Search for a measurement based on measurementId. When searching for a measurement based on Id, all the query parameters listed below are ignored.
source
Search for measurements based on the device identifier or asset identifier of the source.
type
Search for measurements based on the type.
fragmentType
Search for measurements based on the fragment type.
fromDate
Search for measurements from a start date. The date and time is provided as seconds since the epoch.
toDate
Search for measurements within a time range. This is to be used in combination with fromDate. The date and time is provided as seconds since the epoch.
pageSize
Indicates how many entries of the collection are to be retrieved from Cumulocity IoT.
revert
Boolean parameter. By default, Cumulocity returns the oldest measurements first. You can reverse the order by adding the query parameter revert=true. This returns the most recent measurement first.

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