Class TerminatingStepFunction

Namespace

Microsoft.Accordant

Assembly

Accordant.dll

A step function that represents background work which will eventually complete. Subclasses must define IsTerminalState to indicate when the work is done, and GetStepResults(IState) to define how the state transitions.

This is used for:

• Test execution: Polling continues until IsTerminalState returns true for all states
• Test generation: Unwinding continues until IsTerminalState returns true

For daemon/fire-and-forget step functions that never terminate, use BaseStepFunction instead.

For simple cases, use Create<TState>(Func<TState, bool>, Action<TState>, string) to create an async operation inline without defining a class.

public abstract class TerminatingStepFunction : BaseStepFunction, IStepFunction

Inheritance

object

BaseStepFunction

TerminatingStepFunction

Implements

IStepFunction

Inherited Members

BaseStepFunction.StepFunctionId

BaseStepFunction.Apply(IState, IReadOnlyList<(IStepFunction, StateGraphNode)>)

BaseStepFunction.ApplyInternal(IState, IReadOnlyList<(IStepFunction, StateGraphNode)>)

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Properties

IsTerminalState

Returns true when this step function's background work is complete. The predicate is evaluated against the current state.

During polling: We keep polling until this returns true for all possible states. During unwinding: We keep applying step functions until this returns true.

public abstract Func<IState, bool> IsTerminalState { get; }

Property Value

Func<IState, bool>

Methods

ApplyInternal(IState)

Sealed implementation that handles the terminal check automatically. Only calls GetStepResults(IState) when the state is not terminal. When terminal, returns the current state unchanged to consume the step function (removing it from the state profile).

protected override sealed IList<StepResult> ApplyInternal(IState state)

Parameters

state IState

Returns

IList<StepResult>

GetStepResults(IState)

Implement this method to define the possible state transitions. This method is only called when IsTerminalState returns false.

For a single deterministic outcome, return a single StepResult. For non-deterministic outcomes, return multiple StepResults.

protected abstract IList<StepResult> GetStepResults(IState state)

Parameters

state IState

The current state (do not mutate directly; clone first).

Returns

IList<StepResult>

The list of possible next states.