Module message_adapter 

MessageAdapter — cross-format-version message-to-command translation.

Problem

A GPKE process started under FV2025-10-01 may still be in-flight when FV2026-10-01 goes live. The counterparty begins sending APERAK messages in the new AHB format before the process completes. The field that signals acceptance may have moved (e.g. a new qualifier in BGM DE 1001), or an additional mandatory DTM has been added.

Without an explicit adapter, each workflow handles this ad-hoc inside its command constructor, making the mapping invisible, untested, and easy to forget when a new release cycle arrives.

Solution

MessageAdapter<W> is the type-system home for all format-version-specific translation logic. An adapter declares which format versions it can handle (accepts_format_version), receives a parsed AnyMessage, and returns the domain command to dispatch.

Adapters are registered in an AdapterRegistry at engine startup. The registry validates at registration time that all format versions in the workflow’s WorkflowVersionPolicy have a registered adapter.

Example

use mako_engine::message_adapter::{AdapterRegistry, MessageAdapter};
use mako_engine::version::FormatVersion;
use mako_engine::error::EngineError;

struct GpkeAperakAdapter;

impl MessageAdapter<GpkeWorkflow> for GpkeAperakAdapter {
    fn accepts_format_version(&self, fv: &FormatVersion) -> bool {
        matches!(fv.as_str(), "FV2025-10-01" | "FV2026-10-01")
    }

    fn adapt(
        &self,
        msg: &dyn std::any::Any,
        fv: &FormatVersion,
    ) -> Result<GpkeCommand, EngineError> {
        // parse `msg` as APERAK and construct the appropriate command
        Ok(GpkeCommand::ReceiveAperak { positive: true })
    }
}

let mut registry: AdapterRegistry<GpkeWorkflow> = AdapterRegistry::new();
registry.register(GpkeAperakAdapter);

Structs

AdapterRegistry

Runtime registry of MessageAdapters for a single workflow type W.

FnAdapter

A simple function-based adapter constructed via FnAdapter::new.

Traits

MessageAdapter

Translates a parsed EDIFACT message into a domain command for workflow W.