DurableTaskAttribute.cs

// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

namespace Microsoft.DurableTask;

/// <summary>
/// Indicates that the attributed class or method represents a durable task.
/// </summary>
/// <remarks>
/// This attribute is meant to be used on class definitions that derive from
/// <see cref="TaskOrchestrator{TInput, TOutput}"/>, <see cref="TaskActivity{TInput, TOutput}"/>,
/// or TaskEntity{TState} from the Microsoft.DurableTask.Entities namespace.
/// It can also be applied to methods used with <see cref="DurableTaskRegistry.AddOrchestratorFunc{TInput, TOutput}(System.Func{TaskOrchestrationContext, TInput, System.Threading.Tasks.Task{TOutput}})"/>
/// or similar overloads to specify a custom name for the orchestrator.
/// It is used specifically by build-time source generators to generate type-safe methods for invoking
/// orchestrations, activities, or registering entities.
/// </remarks>
[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = false, Inherited = false)]
public sealed class DurableTaskAttribute : Attribute
{
    /// <summary>
    /// Initializes a new instance of the <see cref="DurableTaskAttribute"/> class.
    /// </summary>
    /// <param name="name">
    /// The name of the durable task. If not specified, the class name is used as the implied name of the durable task.
    /// </param>
    public DurableTaskAttribute(string? name = null)
    {
        // This logic cannot become too complex as code-generator relies on examining the constructor arguments.
        this.Name = string.IsNullOrEmpty(name) ? default : new TaskName(name!);
    }

    /// <summary>
    /// Gets the name of the durable task.
    /// </summary>
    public TaskName Name { get; }
}