Package io.opentelemetry.api.metrics

Interface LongValueObserver

  • All Superinterfaces:
    AsynchronousInstrument, Instrument
    @ThreadSafe
public interface LongValueObserver
extends AsynchronousInstrument
    ValueObserver is the asynchronous instrument corresponding to ValueRecorder, used to capture values that are treated as individual observations, recorded with the observe(value) method.

    A ValueObserver is a good choice in situations where a measurement is expensive to compute, such that it would be wasteful to compute on every request.

    Example: 

    
 // class YourClass {
 //
 //   private static final Meter meter = OpenTelemetry.getMeterProvider().get("my_library_name");
 //   private static final LongValueObserver cpuObserver =
 //       meter.
 //           .longValueObserverBuilder("cpu_fan_speed")
 //           .setDescription("System CPU fan speed")
 //           .setUnit("ms")
 //           .build();
 //
 //   void init() {
 //     cpuObserver.setUpdater(
 //         new LongValueObserver.Callback<LongResult>() {
 //          @Override
 //           public void update(LongResult result) {
 //             // Get system cpu fan speed
 //             result.observe(cpuFanSpeed);
 //           }
 //         });
 //   }
 // }