WorkflowHandlerRegistry220FDW

The workflow handler registry resolves IStepHandler220FDW implementations for mobile workflows. It acts as the bridge between a workflow's configuration (stored in the Mobile Workflow 220FDW table) and the AL codeunit that contains the step logic.

Overview

• Object type: Codeunit (73167889)
• Access: Public
• Namespace: Aptean.Mesh.SDUI
• Purpose: Resolves which codeunit handles the steps for a given mobile workflow

Aptean Mesh uses a service-locator pattern for workflow handlers, similar to how MobileRPCRegistry220FDW resolves RPC services. Each workflow record stores a Resolver Codeunit ID that identifies which codeunit implements IStepHandler220FDW. At runtime, the registry fires an integration event so that the matching codeunit can return itself as the handler.

Resolution Flow

Workflow Engine
    │
    ├─► WorkflowHandlerRegistry220FDW.ResolveStepHandler(State)
    │       │
    │       ├─► Look up Mobile Workflow 220FDW record
    │       │     using State.Bundle() + State.Workflow()
    │       │
    │       ├─► Read "Resolver Codeunit ID" from the record
    │       │
    │       └─► Fire OnResolveWorkflowHandler(CodeunitId, ...)
    │               │
    │               └─► Subscriber sets StepHandler := this
    │
    └─► Call StepHandler.IsStepRequired / HandleStep / UndoStep

Methods

ResolveStepHandler

procedure ResolveStepHandler(
    State: Codeunit MobileRPCState220FDW
) StepHandler: Interface IStepHandler220FDW

Resolves the step handler for the workflow identified in the given state object.

Parameters:

Name	Type	Direction	Description
State	Codeunit MobileRPCState220FDW	value	The current RPC state. The registry reads State.Bundle() and State.Workflow() to look up the workflow record.

Returns: Interface IStepHandler220FDW -- the resolved step handler implementation.

Errors:

Condition	Error Message
Workflow record not found	Workflow '{WorkflowCode}' not found for App Bundle '{BundleId}'. Ensure the workflow is configured in Mobile Workflows.
No handler subscribed	No workflow handler found for workflow '{WorkflowCode}' (Resolver Codeunit ID: {CodeunitId}). Ensure the codeunit subscribes to OnResolveWorkflowHandler event.

Integration Event

OnResolveWorkflowHandler

[IntegrationEvent(false, false)]
local procedure OnResolveWorkflowHandler(
    CodeunitId: Integer;
    var StepHandler: Interface IStepHandler220FDW;
    var IsResolved: Boolean)

Fired by the registry when it needs to resolve a workflow handler. Subscribe to this event in your codeunit to register yourself as the handler for a specific codeunit ID.

Parameters:

Name	Type	Direction	Description
CodeunitId	Integer	value	The Resolver Codeunit ID from the Mobile Workflow 220FDW record. Compare this to your own Codeunit:: identifier.
StepHandler	Interface IStepHandler220FDW	var	Set this to your codeunit instance (this) when the CodeunitId matches.
IsResolved	Boolean	var	Set to true after assigning StepHandler. Check this first -- if another subscriber already resolved the handler, exit immediately.

Registration Example

The following example shows how to register a custom workflow handler. This pattern is identical to the one used by the built-in ReceiptService220FDW.

codeunit 50100 "My Workflow Handler" implements IStepHandler220FDW
{
    [EventSubscriber(ObjectType::Codeunit,
        Codeunit::WorkflowHandlerRegistry220FDW,
        OnResolveWorkflowHandler, '', false, false)]
    local procedure ResolveMyHandler(
        CodeunitId: Integer;
        var StepHandler: Interface IStepHandler220FDW;
        var IsResolved: Boolean)
    begin
        // Guard: another subscriber already resolved
        if IsResolved then
            exit;

        // Guard: this event is not for our codeunit
        if CodeunitId <> Codeunit::"My Workflow Handler" then
            exit;

        // Register ourselves as the handler
        StepHandler := this;
        IsResolved := true;
    end;

    // Implement IStepHandler220FDW methods...
    procedure IsStepRequired(
        var State: Codeunit MobileRPCState220FDW;
        var ItemMgt: Codeunit MobileItemMgt220FDW;
        WorkflowStep: Record "Mobile Workflow Step 220FDW"): Boolean
    begin
        // Step-type dispatch logic
        exit(true);
    end;

    procedure HandleStep(
        var State: Codeunit MobileRPCState220FDW;
        var ItemMgt: Codeunit MobileItemMgt220FDW;
        WorkflowStep: Record "Mobile Workflow Step 220FDW"): Boolean
    begin
        // Step execution logic
        exit(true);
    end;

    procedure UndoStep(
        var State: Codeunit MobileRPCState220FDW;
        var ItemMgt: Codeunit MobileItemMgt220FDW;
        WorkflowStep: Record "Mobile Workflow Step 220FDW"): Boolean
    begin
        // Step undo logic
        exit(false);
    end;
}

Workflow Configuration Tables

The registry depends on two tables that define which workflows exist and what steps they contain.

Mobile Workflow 220FDW

Stores the workflow definitions for each app bundle.

Field	Type	Description
App Bundle ID	Guid	Foreign key to the Mobile App Bundle 220FDW table.
Workflow Code	Code[20]	Unique identifier for the workflow within the bundle (e.g., RECEIPT, PUTAWAY).
Description	Text[100]	Human-readable description of the workflow's purpose.
Resolver Codeunit ID	Integer	The codeunit that implements IStepHandler220FDW for this workflow. This is the ID passed to OnResolveWorkflowHandler.

Primary key: App Bundle ID + Workflow Code

Mobile Workflow Step 220FDW

Stores the ordered steps within each workflow.

Field	Type	Description
App Bundle ID	Guid	Foreign key to the parent workflow's bundle.
Workflow Code	Code[20]	Foreign key to the parent workflow.
Sequence	Integer	Execution order within the workflow. Lower numbers execute first. Auto-assigned in increments of 10.
Step Type	Enum StepType220FDW	The type of data to capture (Bin, Item, LotNumber, Quantity, etc.).
Step Input Type	Enum StepInputType220FDW	The UI input control to display on the mobile device (Barcode, Numeric, DatePicker, Image, Choice, etc.).
Instruction	Text[50]	The text prompt shown to the user on the mobile device.
GS1 AI	Code[30]	GS1 Application Identifiers for barcode parsing, separated by semicolons (e.g., 01;02).

Primary key: App Bundle ID + Workflow Code + Sequence

The step table also provides helper methods:

• SetWorkflowFilters(BundleId, WorkflowCode) -- sets filters and sorts by sequence for iteration
• GetFirstSequence() -- returns the lowest sequence number in the current filter
• FindByStepType(StepType) -- positions the record on the first step matching the given type

Setup in Business Central

To wire a workflow to your handler codeunit:

1. Open Mobile App Bundles and select your bundle
2. Open Mobile Workflows from the bundle card
3. Create a workflow record:
   • Workflow Code -- e.g., MYWORKFLOW (must match the workflow code sent by the mobile client)
   • Resolver Codeunit ID -- e.g., 50100 (the object ID of your IStepHandler220FDW codeunit)
4. Open Workflow Steps from the workflow card and add steps in sequence:
   • Set the Step Type (e.g., LotNumber, Quantity, Bin)
   • Set the Step Input Type for the mobile UI control
   • Optionally set an Instruction and GS1 AI identifiers

Dual Registration Pattern

Most Aptean Mesh service codeunits implement both IBCRPC220FDW (for RPC dispatch) and IStepHandler220FDW (for workflow steps) on the same codeunit. This means the codeunit subscribes to two registry events:

codeunit 50100 "My Service" implements IBCRPC220FDW, IStepHandler220FDW
{
    // Register as an RPC service
    [EventSubscriber(ObjectType::Codeunit,
        Codeunit::MobileRPCRegistry220FDW,
        OnResolveService, '', false, false)]
    local procedure ResolveService(
        CodeunitId: Integer;
        var Service: Interface IBCRPC220FDW;
        var IsServiceResolved: Boolean)
    begin
        if IsServiceResolved then exit;
        if CodeunitId <> Codeunit::"My Service" then exit;
        Service := this;
        IsServiceResolved := true;
    end;

    // Register as a workflow handler
    [EventSubscriber(ObjectType::Codeunit,
        Codeunit::WorkflowHandlerRegistry220FDW,
        OnResolveWorkflowHandler, '', false, false)]
    local procedure ResolveWorkflowHandler(
        CodeunitId: Integer;
        var StepHandler: Interface IStepHandler220FDW;
        var IsResolved: Boolean)
    begin
        if IsResolved then exit;
        if CodeunitId <> Codeunit::"My Service" then exit;
        StepHandler := this;
        IsResolved := true;
    end;

    // IBCRPC220FDW implementation
    procedure RPC(var State: Codeunit MobileRPCState220FDW) ResponseJson: JsonObject
    begin
        case State.Method() of
            'Initialize':
                Initialize(State);
            'HandleWorkFlow':
                HandleWorkFlow(State);
            'UndoStep':
                ProcessUndoStep(State);
        end;
        ResponseJson := State.Serialize();
    end;

    // IStepHandler220FDW implementation
    procedure IsStepRequired(
        var State: Codeunit MobileRPCState220FDW;
        var ItemMgt: Codeunit MobileItemMgt220FDW;
        WorkflowStep: Record "Mobile Workflow Step 220FDW"): Boolean
    begin
        // ...
    end;

    procedure HandleStep(
        var State: Codeunit MobileRPCState220FDW;
        var ItemMgt: Codeunit MobileItemMgt220FDW;
        WorkflowStep: Record "Mobile Workflow Step 220FDW"): Boolean
    begin
        // ...
    end;

    procedure UndoStep(
        var State: Codeunit MobileRPCState220FDW;
        var ItemMgt: Codeunit MobileItemMgt220FDW;
        WorkflowStep: Record "Mobile Workflow Step 220FDW"): Boolean
    begin
        // ...
    end;
}

In this pattern, the RPC method's 'HandleWorkFlow' branch typically calls WorkflowHandlerRegistry220FDW.ResolveStepHandler(State) to obtain the handler, then iterates through the workflow steps calling IsStepRequired, HandleStep, and UndoStep as needed.

See Also

• IStepHandler220FDW -- the interface contract for workflow step handlers
• IBCRPC220FDW -- the RPC service interface, often implemented on the same codeunit
• MobileRPCRegistry220FDW -- the RPC service registry (analogous pattern)
• MobileRPCState220FDW -- request parsing, state management, and response building
• Enums -- StepType220FDW and StepInputType220FDW reference