openconsensus.metrics

Interface DerivedLongGauge

All Superinterfaces:

Metric

@ThreadSafe
public interface DerivedLongGauge
extends Metric

Derived Long Gauge metric, to report instantaneous measurement of an int64 value. Gauges can go both up and down. The gauges values can be negative.

Example: Create a Gauge with an object and a callback function.

 class YourClass {

   private static final Meter meter = Metrics.getMeter();
   private static final MetricRegistry metricRegistry = meter.metricRegistryBuilder().build();

   List<LabelKey> labelKeys = Arrays.asList(LabelKey.create("Name", "desc"));
   List<LabelValue> labelValues = Arrays.asList(LabelValue.create("Inbound"));

   DerivedLongGauge gauge = metricRegistry.addDerivedLongGauge(
       "queue_size", "Pending jobs in a queue", "1", labelKeys);

   QueueManager queueManager = new QueueManager();
   gauge.createTimeSeries(labelValues, queueManager,
         new ToLongFunction<QueueManager>() {
           {@literal @}Override
           public long applyAsLong(QueueManager queue) {
             return queue.size();
           }
         });

   void doWork() {
      // Your code here.
   }
 }

 

Since:

0.1.0

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	DerivedLongGauge.Builder Builder class for DerivedLongGauge.

Method Summary

Modifier and Type	Method and Description
<T> void	createTimeSeries(List<LabelValue> labelValues, T obj, ToLongFunction<T> function) Creates a TimeSeries.

Methods inherited from interface openconsensus.metrics.Metric

clear, removeTimeSeries

Method Detail

createTimeSeries

<T> void createTimeSeries(List<LabelValue> labelValues,
                          T obj,
                          ToLongFunction<T> function)

Creates a TimeSeries. The value of a single point in the TimeSeries is observed from a callback function. This function is invoked whenever metrics are collected, meaning the reported value is up-to-date. It keeps a WeakReference to the object and it is the user's responsibility to manage the lifetime of the object.

Type Parameters:

T - the type of the object upon which the function derives a measurement.

Parameters:

labelValues - the list of label values.

obj - the state object from which the function derives a measurement.

function - the function to be called.

Throws:

NullPointerException - if labelValues is null OR any element of labelValues is null OR function is null.

IllegalArgumentException - if different time series with the same labels already exists OR if number of labelValuess are not equal to the label keys.

Since:

0.1.0