How to: Author a workflow

public class NotifyActivity : WorkflowActivity<Notification, object>
{
    //...

    public NotifyActivity(ILoggerFactory loggerFactory)
    {
        this.logger = loggerFactory.CreateLogger<NotifyActivity>();
    }

    //...
}

public class ReserveInventoryActivity : WorkflowActivity<InventoryRequest, InventoryResult>
{
    //...

    public ReserveInventoryActivity(ILoggerFactory loggerFactory, DaprClient client)
    {
        this.logger = loggerFactory.CreateLogger<ReserveInventoryActivity>();
        this.client = client;
    }

    //...

}

public class ProcessPaymentActivity : WorkflowActivity<PaymentRequest, object>
{
    //...
    public ProcessPaymentActivity(ILoggerFactory loggerFactory)
    {
        this.logger = loggerFactory.CreateLogger<ProcessPaymentActivity>();
    }

    //...

}

@JsonAutoDetect(fieldVisibility = JsonAutoDetect.Visibility.ANY)
public class DemoWorkflowActivity implements WorkflowActivity {

  @Override
  public DemoActivityOutput run(WorkflowActivityContext ctx) {
    Logger logger = LoggerFactory.getLogger(DemoWorkflowActivity.class);
    logger.info("Starting Activity: " + ctx.getName());

    var message = ctx.getInput(DemoActivityInput.class).getMessage();
    var newMessage = message + " World!, from Activity";
    logger.info("Message Received from input: " + message);
    logger.info("Sending message to output: " + newMessage);

    logger.info("Sleeping for 5 seconds to simulate long running operation...");

    try {
      TimeUnit.SECONDS.sleep(5);
    } catch (InterruptedException e) {
      throw new RuntimeException(e);
    }


    logger.info("Activity finished");

    var output = new DemoActivityOutput(message, newMessage);
    logger.info("Activity returned: " + output);

    return output;
  }
}

 class OrderProcessingWorkflow : Workflow<OrderPayload, OrderResult>
    {
        public override async Task<OrderResult> RunAsync(WorkflowContext context, OrderPayload order)
        {
            //...

            await context.CallActivityAsync(
                nameof(NotifyActivity),
                new Notification($"Received order {orderId} for {order.Name} at {order.TotalCost:c}"));

            //...

            InventoryResult result = await context.CallActivityAsync<InventoryResult>(
                nameof(ReserveInventoryActivity),
                new InventoryRequest(RequestId: orderId, order.Name, order.Quantity));
            //...
            
            await context.CallActivityAsync(
                nameof(ProcessPaymentActivity),
                new PaymentRequest(RequestId: orderId, order.TotalCost, "USD"));

            await context.CallActivityAsync(
                nameof(NotifyActivity),
                new Notification($"Order {orderId} processed successfully!"));

            // End the workflow with a success result
            return new OrderResult(Processed: true);
        }
    }

public class DemoWorkflowWorker {

  public static void main(String[] args) throws Exception {

    // Register the Workflow with the builder.
    WorkflowRuntimeBuilder builder = new WorkflowRuntimeBuilder().registerWorkflow(DemoWorkflow.class);
    builder.registerActivity(DemoWorkflowActivity.class);

    // Build and then start the workflow runtime pulling and executing tasks
    try (WorkflowRuntime runtime = builder.build()) {
      System.out.println("Start workflow runtime");
      runtime.start();
    }

    System.exit(0);
  }
}

using Dapr.Workflow;
//...

// Dapr Workflows are registered as part of the service configuration
builder.Services.AddDaprWorkflow(options =>
{
    // Note that it's also possible to register a lambda function as the workflow
    // or activity implementation instead of a class.
    options.RegisterWorkflow<OrderProcessingWorkflow>();

    // These are the activities that get invoked by the workflow(s).
    options.RegisterActivity<NotifyActivity>();
    options.RegisterActivity<ReserveInventoryActivity>();
    options.RegisterActivity<ProcessPaymentActivity>();
});

WebApplication app = builder.Build();

// POST starts new order workflow instance
app.MapPost("/orders", async (DaprWorkflowClient client, [FromBody] OrderPayload orderInfo) =>
{
    if (orderInfo?.Name == null)
    {
        return Results.BadRequest(new
        {
            message = "Order data was missing from the request",
            example = new OrderPayload("Paperclips", 99.95),
        });
    }

//...
});

// GET fetches state for order workflow to report status
app.MapGet("/orders/{orderId}", async (string orderId, DaprWorkflowClient client) =>
{
    WorkflowState state = await client.GetWorkflowStateAsync(orderId, true);
    if (!state.Exists)
    {
        return Results.NotFound($"No order with ID = '{orderId}' was found.");
    }

    var httpResponsePayload = new
    {
        details = state.ReadInputAs<OrderPayload>(),
        status = state.RuntimeStatus.ToString(),
        result = state.ReadOutputAs<OrderResult>(),
    };

//...
}).WithName("GetOrderInfoEndpoint");

app.Run();

package io.dapr.examples.workflows;

import com.microsoft.durabletask.CompositeTaskFailedException;
import com.microsoft.durabletask.Task;
import com.microsoft.durabletask.TaskCanceledException;
import io.dapr.workflows.Workflow;
import io.dapr.workflows.WorkflowStub;

import java.time.Duration;
import java.util.Arrays;
import java.util.List;

/**
 * Implementation of the DemoWorkflow for the server side.
 */
public class DemoWorkflow extends Workflow {
  @Override
  public WorkflowStub create() {
    return ctx -> {
      ctx.getLogger().info("Starting Workflow: " + ctx.getName());
      // ...
      ctx.getLogger().info("Calling Activity...");
      var input = new DemoActivityInput("Hello Activity!");
      var output = ctx.callActivity(DemoWorkflowActivity.class.getName(), input, DemoActivityOutput.class).await();
      // ...
    };
  }
}