Package io.opentelemetry.api.metrics

Interface DoubleUpDownSumObserver

  • All Superinterfaces:
    AsynchronousInstrument, Instrument
    @ThreadSafe
public interface DoubleUpDownSumObserver
extends AsynchronousInstrument
    UpDownSumObserver is the asynchronous instrument corresponding to UpDownCounter, used to capture a non-monotonic count with Observe(sum).

    "Sum" appears in the name to remind that it is used to capture sums directly. Use a UpDownSumObserver to capture any value that starts at zero and rises or falls throughout the process lifetime.

    A UpDownSumObserver 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 DoubleUpDownSumObserver memoryObserver =
 //       meter.
 //           .doubleUpDownSumObserverBuilder("memory_usage")
 //           .setDescription("System memory usage")
 //           .setUnit("by")
 //           .build();
 //
 //   void init() {
 //     memoryObserver.setUpdater(
 //         new DoubleUpDownSumObserver.Callback<DoubleResult>() {
 //          @Override
 //           public void update(DoubleResult result) {
 //             // Get system memory usage
 //             result.observe(memoryUsed, "state", "used");
 //             result.observe(memoryFree, "state", "free");
 //           }
 //         });
 //   }
 // }