AsynchronousInstrument (opentelemetry-api 0.10.0 API)

Type Parameters:

R - the callback Result type.

All Superinterfaces:

Instrument

All Known Subinterfaces:

DoubleSumObserver, DoubleUpDownSumObserver, DoubleValueObserver, LongSumObserver, LongUpDownSumObserver, LongValueObserver
```
@ThreadSafe
public interface AsynchronousInstrument<R extends AsynchronousInstrument.Result>
extends Instrument
```
AsynchronousInstrument is an interface that defines a type of instruments that are used to report measurements asynchronously.
They are reported by a callback, once per collection interval, and lack Context. They are permitted to report only one value per distinct label set per period. If the application observes multiple values for the same label set, in a single callback, the last value is the only value kept.

Nested Class Summary

Nested Classes
Modifier and Type	Interface	Description
`static interface`	`AsynchronousInstrument.Builder`	Builder class for `AsynchronousInstrument`.
`static interface`	`AsynchronousInstrument.Callback<R extends AsynchronousInstrument.Result>`	A `Callback` for a `AsynchronousInstrument`.
`static interface`	`AsynchronousInstrument.DoubleResult`	The result for the `AsynchronousInstrument.Callback`.
`static interface`	`AsynchronousInstrument.LongResult`	The result for the `AsynchronousInstrument.Callback`.
`static interface`	`AsynchronousInstrument.Result`

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`setCallback(AsynchronousInstrument.Callback<R> callback)`	Sets a callback that gets executed every collection interval.

- Method Detail
  - setCallback
```
void setCallback(AsynchronousInstrument.Callback<R> callback)
```
    Sets a callback that gets executed every collection interval.
    Evaluation is deferred until needed, if this AsynchronousInstrument metric is not exported then it will never be called.
    
    Parameters:
    
    callback - the callback to be executed before export.