/// <summary>
/// Starts the target activity that returns <typeparamref name="TResult"/>, passing the specified arguments.
/// </summary>
/// <typeparam name="TResult">The activity result type.</typeparam>
/// <param name="args">The arguments to be passed to the activity.</param>
/// <returns>The <see cref="IAsyncFuture{T}"/> with the <see cref="IAsyncFuture{T}.GetAsync"/> that can be used to retrieve the workfow result.</returns>
/// <exception cref="InvalidOperationException">Thrown when attempting to start a future stub more than once.</exception>
/// <remarks>
/// <para>
/// You must take care to pass parameters that are compatible with the target activity parameters.
/// These are checked at runtime but not while compiling.
/// </para>
/// <note>
/// Any given <see cref="ActivityFutureStub{TActivityInterface}"/> may only be executed once.
/// </note>
/// </remarks>
public async Task <IAsyncFuture <TResult> > StartAsync <TResult>(params object[] args)
{
await SyncContext.Clear;
Covenant.Requires <ArgumentNullException>(parentWorkflow != null, nameof(parentWorkflow));
parentWorkflow.SetStackTrace();
if (hasStarted)
{
throw new InvalidOperationException("Cannot start a future stub more than once.");
}
hasStarted = true;
// Start the activity.
var client = parentWorkflow.Client;
var dataConverter = client.DataConverter;
var activityId = parentWorkflow.GetNextActivityId();
var reply = await parentWorkflow.ExecuteNonParallel(
async() =>
{
return((ActivityStartReply)await client.CallProxyAsync(
new ActivityStartRequest()
{
ContextId = parentWorkflow.ContextId,
ActivityId = activityId,
Activity = activityTypeName,
Args = CadenceHelper.ArgsToBytes(dataConverter, args),
Options = options.ToInternal(),
Domain = options.Domain
}));
});
reply.ThrowOnError();
parentWorkflow.UpdateReplay(reply);
// Create and return the future.
return(new AsyncFuture <TResult>(parentWorkflow, activityId));
}
/// <summary>
/// Starts the target activity that returns <typeparamref name="TActivityInterface"/>, passing the specified arguments.
/// </summary>
/// <typeparam name="TResult">The activity result type.</typeparam>
/// <param name="args">The arguments to be passed to the activity.</param>
/// <returns>The <see cref="IAsyncFuture{T}"/> with the <see cref="IAsyncFuture{T}.GetAsync"/> that can be used to retrieve the workfow result.</returns>
/// <exception cref="InvalidOperationException">Thrown when attempting to start a future stub more than once.</exception>
/// <remarks>
/// <para>
/// You must take care to pass parameters that are compatible with the target activity parameters.
/// These are checked at runtime but not while compiling.
/// </para>
/// <note>
/// Any given <see cref="ActivityFutureStub{TActivityInterface}"/> may only be executed once.
/// </note>
/// </remarks>
public async Task <IAsyncFuture <TResult> > StartAsync <TResult>(params object[] args)
{
await SyncContext.Clear;
Covenant.Requires <ArgumentNullException>(parentWorkflow != null, nameof(parentWorkflow));
parentWorkflow.SetStackTrace();
if (hasStarted)
{
throw new InvalidOperationException("Cannot start a future stub more than once.");
}
var parameters = targetMethod.GetParameters();
if (parameters.Length != args.Length)
{
throw new ArgumentException($"Invalid number of parameters: [{parameters.Length}] expected but [{args.Length}] were passed.", nameof(parameters));
}
hasStarted = true;
// Cast the input parameters to the target types so that developers won't need to expicitly
// cast things like integers into longs, floats into doubles, etc.
for (int i = 0; i < args.Length; i++)
{
args[i] = CadenceHelper.ConvertArg(parameters[i].ParameterType, args[i]);
}
// Validate the return type.
var resultType = targetMethod.ReturnType;
if (resultType == typeof(Task))
{
throw new ArgumentException($"Activity method [{nameof(TActivityInterface)}.{targetMethod.Name}()] does not return [void].", nameof(TActivityInterface));
}
resultType = resultType.GenericTypeArguments.First();
if (!resultType.IsAssignableFrom(typeof(TResult)))
{
throw new ArgumentException($"Activity method [{nameof(TActivityInterface)}.{targetMethod.Name}()] returns [{resultType.FullName}] which is not compatible with [{nameof(TResult)}].", nameof(TActivityInterface));
}
// Start the activity.
var dataConverter = client.DataConverter;
var activityId = parentWorkflow.GetNextActivityId();
var reply = await parentWorkflow.ExecuteNonParallel(
async() =>
{
return((ActivityStartReply)await client.CallProxyAsync(
new ActivityStartRequest()
{
ContextId = parentWorkflow.ContextId,
ActivityId = activityId,
Activity = activityTypeName,
Args = CadenceHelper.ArgsToBytes(dataConverter, args),
Options = options.ToInternal(),
Domain = options.Domain
}));
});
reply.ThrowOnError();
parentWorkflow.UpdateReplay(reply);
// Create and return the future.
return(new AsyncFuture <TResult>(parentWorkflow, activityId));
}