Execution Lifecycle

Introduction

This page describes the runtime execution flow visible in the current code base. It focuses on the actual collaboration between the application, request handlers, and the router.

Step-by-Step Flow

  1. The host or UI resolves a request handler from the application using a compiled registration key.
  2. The application signs into the handler's RequestServiceEvent.
  3. The handler receives an ITransitionContext and treats it as both request and initial response context.
  4. ProcessRequest performs local work for the current layer.
  5. If execution should continue, the handler raises RequestToNextLayerEventArgs.
  6. BPUAApplication receives the service request event and resolves the matching BPUA service from the registry.
  7. TransitionContextRouter calculates the next layer and invokes the next transition handler.
  8. The nested handler repeats the same pattern until no next layer exists.
  9. On the way back, handlers perform ProcessResponse and optional asynchronous response processing.

Why This Flow Matters

The important architectural idea is that transition execution is neither a direct call chain nor a controller pipeline. It is a request-handler pipeline coordinated through events, registry-based service lookup, and explicit layer progression.

Transition Context as the Carrier

The transition context is the thing that moves through the lifecycle. The router augments it with request metadata while the handlers use it as the carrier of process state and response state. This page does not redefine transition context conceptually; it shows its runtime role in the current implementation.

Summary

The execution lifecycle is the runtime form of BPUA's transition pipeline. Each layer performs its work, delegates through the router, and then participates in the response path.

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Business Process Programming in .Net
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