/// <summary>
/// Starts the target workflow that returns <typeparamref name="TResult"/>, passing any specified arguments.
/// </summary>
/// <typeparam name="TResult">The workflow result type.</typeparam>
/// <param name="args">The arguments to be passed to the workflow.</param>
/// <returns>The <see cref="ChildWorkflowFuture{T}"/> with the <see cref="ChildWorkflowFuture{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 workflow parameters.
/// These are checked at runtime but not while compiling.
/// </para>
/// <note>
/// Any given <see cref="ChildWorkflowStub{TWorkflowInterface}"/> may only be executed once.
/// </note>
/// </remarks>
public async Task <ChildWorkflowFuture <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($"Invalid number of parameters: [{parameters.Length}] expected but [{args.Length}] were passed.", nameof(parameters));
}
hasStarted = true;
// Cast the input parameters to the target types so that developers won't need to expicitly
// cast things like integers into longs, floats into doubles, etc.
for (int i = 0; i < args.Length; i++)
{
args[i] = TemporalHelper.ConvertArg(parameters[i].ParameterType, args[i]);
}
// Start the child workflow and then construct and return the future.
var client = parentWorkflow.Client;
var execution = await client.StartChildWorkflowAsync(parentWorkflow, workflowTypeName, TemporalHelper.ArgsToBytes(client.DataConverter, args), options);
// Initialize the type-safe stub property such that developers can call
// any query or signal methods.
Stub = StubManager.NewChildWorkflowStub <TWorkflowInterface>(client, parentWorkflow, workflowTypeName, execution);
// Create and return the future.
var resultType = targetMethod.ReturnType;
if (resultType == typeof(Task))
{
throw new ArgumentException($"Workflow method [{nameof(TWorkflowInterface)}.{targetMethod.Name}()] does not return [void].", nameof(TWorkflowInterface));
}
resultType = resultType.GenericTypeArguments.First();
if (!resultType.IsAssignableFrom(typeof(TResult)))
{
throw new ArgumentException($"Workflow method [{nameof(TWorkflowInterface)}.{targetMethod.Name}()] returns [{resultType.FullName}] which is not compatible with [{nameof(TResult)}].", nameof(TWorkflowInterface));
}
return(new ChildWorkflowFuture <TResult>(parentWorkflow, execution));
}
/// <summary>
/// Starts the target workflow that returns <c>void</c>, passing any specified arguments.
/// </summary>
/// <param name="args">The arguments to be passed to the workflow.</param>
/// <returns>The <see cref="ChildWorkflowFuture{T}"/> with the <see cref="ChildWorkflowFuture{T}.GetAsync"/> than can be used to retrieve the workfow result.</returns>
/// <exception cref="InvalidOperationException">Thrown when attempting to start a future stub more than once.</exception>
/// <remarks>
/// <para>
/// You must take care to pass parameters that are compatible with the target workflow parameters.
/// These are checked at runtime but not while compiling.
/// </para>
/// <note>
/// Any given <see cref="ChildWorkflowStub{TWorkflowInterface}"/> may only be executed once.
/// </note>
/// </remarks>
public async Task <ChildWorkflowFuture> StartAsync(params object[] args)
{
await SyncContext.ClearAsync;
Covenant.Requires <ArgumentNullException>(parentWorkflow != null, nameof(parentWorkflow));
parentWorkflow.SetStackTrace();
if (hasStarted)
{
throw new InvalidOperationException("Cannot start a future stub more than once.");
}
var parameters = targetMethod.GetParameters();
if (parameters.Length != args.Length)
{
throw new ArgumentException($"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] = TypeDescriptor.GetConverter(parameters[i].ParameterType).ConvertTo(args[i], parameters[i].ParameterType);
}
// Start the child workflow and then construct the future.
var client = parentWorkflow.Client;
var execution = await client.StartChildWorkflowAsync(parentWorkflow, workflowTypeName, client.DataConverter.ToData(args), options);
// Initialize the type-safe stub property such that developers can call
// any query or signal methods.
Stub = StubManager.NewChildWorkflowStub <TWorkflowInterface>(client, parentWorkflow, workflowTypeName, execution);
// Create and return the future.
return(new ChildWorkflowFuture(parentWorkflow, execution));
}