io.opencensus.metrics

Class DerivedDoubleCumulative

java.lang.Object

io.opencensus.metrics.DerivedDoubleCumulative

@ThreadSafe
public abstract class DerivedDoubleCumulative
extends Object

Derived Double Cumulative metric, to report cumulative measurement of a double value. Cumulative values can go up or stay the same, but can never go down. Cumulative values cannot be negative.

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

 class YourClass {

   private static final MetricRegistry metricRegistry = Metrics.getMetricRegistry();

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

   DerivedDoubleCumulative cumulative = metricRegistry.addDerivedDoubleCumulative(
       "processed_jobs", "Processed jobs in a queue", "1", labelKeys);

   QueueManager queueManager = new QueueManager();
   cumulative.createTimeSeries(labelValues, queueManager,
         new ToDoubleFunction<QueueManager>() {
           {@literal @}Override
           public double applyAsDouble(QueueManager queue) {
             return queue.size();
           }
         });

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

 

Since:

0.21

Constructor Summary

Constructors

Constructor and Description
DerivedDoubleCumulative()

Method Summary

Modifier and Type	Method and Description
abstract void	clear() Removes all TimeSeries from the cumulative metric.
abstract <T> void	createTimeSeries(List<LabelValue> labelValues, T obj, ToDoubleFunction<T> function) Creates a TimeSeries.
abstract void	removeTimeSeries(List<LabelValue> labelValues) Removes the TimeSeries from the cumulative metric, if it is present.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DerivedDoubleCumulative

public DerivedDoubleCumulative()

Method Detail

createTimeSeries

public abstract <T> void createTimeSeries(List<LabelValue> labelValues,
                                          T obj,
                                          ToDoubleFunction<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:

0.21

removeTimeSeries

public abstract void removeTimeSeries(List<LabelValue> labelValues)

Removes the TimeSeries from the cumulative metric, if it is present.

Parameters:

labelValues - the list of label values.

Throws:

NullPointerException - if labelValues is null.

Since:

0.21

clear

public abstract void clear()

Removes all TimeSeries from the cumulative metric.

Since:

0.21