DoubleAccumulator Class

Definition

[Android.Runtime.Register("java/util/concurrent/atomic/DoubleAccumulator", ApiSince=24, DoNotGenerateAcw=true)]
public class DoubleAccumulator : Java.Lang.Number, IDisposable, Java.Interop.IJavaPeerable

[<Android.Runtime.Register("java/util/concurrent/atomic/DoubleAccumulator", ApiSince=24, DoNotGenerateAcw=true)>]
type DoubleAccumulator = class
    inherit Number
    interface ISerializable
    interface IJavaObject
    interface IDisposable
    interface IJavaPeerable

Inheritance

Object

Object

Number

DoubleAccumulator

Attributes

RegisterAttribute

Implements

IJavaObject IJavaPeerable ISerializable IDisposable

Remarks

One or more variables that together maintain a running double value updated using a supplied function. When updates (method #accumulate) are contended across threads, the set of variables may grow dynamically to reduce contention. Method #get (or, equivalently, #doubleValue) returns the current value across the variables maintaining updates.

This class is usually preferable to alternatives when multiple threads update a common value that is used for purposes such as summary statistics that are frequently updated but less frequently read.

The supplied accumulator function should be side-effect-free, since it may be re-applied when attempted updates fail due to contention among threads. For predictable results, the accumulator function should be commutative and associative within the floating point tolerance required in usage contexts. The function is applied with an existing value (or identity) as one argument, and a given update as the other argument. For example, to maintain a running maximum value, you could supply Double::max along with Double.NEGATIVE_INFINITY as the identity. The order of accumulation within or across threads is not guaranteed. Thus, this class may not be applicable if numerical stability is required, especially when combining values of substantially different orders of magnitude.

Class DoubleAdder provides analogs of the functionality of this class for the common special case of maintaining sums. The call new DoubleAdder() is equivalent to new DoubleAccumulator((x, y) -> x + y, 0.0).

This class extends Number, but does <em>not</em> define methods such as equals, hashCode and compareTo because instances are expected to be mutated, and so are not useful as collection keys.

Added in 1.8.

Java documentation for java.util.concurrent.atomic.DoubleAccumulator.

Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.

Constructors

Properties

Methods

Explicit Interface Implementations

Extension Methods

Applies to