Class AsyncCounter

Represents a synchronization primitive that is signaled when its count becomes non-zero.

Inheritance
object
Disposable
QueuedSynchronizer
AsyncCounter
Implements
Inherited Members
Namespace: DotNext.Threading
Assembly: DotNext.Threading.dll
Syntax
public class AsyncCounter : QueuedSynchronizer, IAsyncEvent, IDisposable, IResettable
Remarks

This class behaves in opposite to AsyncCountdownEvent. Every call of Increment() increments the counter. Every call of WaitAsync(TimeSpan, CancellationToken) decrements counter and release the caller if the current count is greater than zero.

Constructors

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AsyncCounter(long)

Initializes a new asynchronous counter.

Declaration
public AsyncCounter(long initialValue = 0)
Parameters
Type Name Description
long initialValue

The initial value of the counter.
Exceptions
Type Condition
ArgumentOutOfRangeException

initialValue is less than zero.

Properties

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Value

Gets the counter value.

Declaration
public long Value { get; }
Property Value
Type Description
long
Remarks

The returned value indicates how many calls you can perform using WaitAsync(TimeSpan, CancellationToken) without blocking.

Methods

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Increment()

Increments counter and resume suspended callers.

Declaration
public void Increment()
Exceptions
Type Condition
OverflowException

Counter overflow detected.
ObjectDisposedException

This object is disposed.
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Increment(long)

Increments counter and resume suspended callers.

Declaration
public void Increment(long delta)
Parameters
Type Name Description
long delta

The value to be added to the counter.
Exceptions
Type Condition
ArgumentOutOfRangeException

delta is less than zero.
ObjectDisposedException

This object is disposed.
OverflowException

Counter overflow detected.
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TryDecrement()

Attempts to decrement the counter synchronously.

Declaration
public bool TryDecrement()
Returns
Type Description
bool

true if the counter decremented successfully; false if this counter is already zero.
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TryIncrement(long)

Attempts to increment this counter.

Declaration
public bool TryIncrement(long maxValue)
Parameters
Type Name Description
long maxValue

The maximum allowed value of this counter.
Returns
Type Description
bool

true if successfully incremented; false on overflow.
Exceptions
Type Condition
ArgumentOutOfRangeException

maxValue is negative or zero.
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WaitAsync(CancellationToken)

Suspends caller if Value is zero or just decrements it.

Declaration
public ValueTask WaitAsync(CancellationToken token = default)
Parameters
Type Name Description
CancellationToken token

The token that can be used to cancel the waiting operation.
Returns
Type Description
ValueTask

The task representing asynchronous result.
Exceptions
Type Condition
OperationCanceledException

The operation has been canceled.
ObjectDisposedException

This object is disposed.
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WaitAsync(TimeSpan, CancellationToken)

Suspends caller if Value is zero or just decrements it.

Declaration
public ValueTask<bool> WaitAsync(TimeSpan timeout, CancellationToken token = default)
Parameters
Type Name Description
TimeSpan timeout

Time to wait for increment.
CancellationToken token

The token that can be used to cancel the waiting operation.
Returns
Type Description
ValueTask<bool>

true if counter is decremented successfully; otherwise, false.
Exceptions
Type Condition
OperationCanceledException

The operation has been canceled.
ObjectDisposedException

This object is disposed.

Implements

Extension Methods