Why should you care?

ShopNest inventory still talks to a legacy SOAP warehouse while the app expects IStockClient.

See it live — copy this example

Paste into a C# console or class library project and run dotnet run.

public interface IStockClient { int GetQty(string sku); }
public sealed class LegacyWarehouseSdk
{
    public int FetchAvailable(string code) => 42; // legacy shape
}
public sealed class WarehouseStockAdapter : IStockClient
{
    private readonly LegacyWarehouseSdk _sdk = new();
    public int GetQty(string sku) => _sdk.FetchAvailable(sku);
}

IStockClient stock = new WarehouseStockAdapter();
Console.WriteLine(stock.GetQty("HD-100"));

Run Example »

Edit the code below and click Run to see the result in Toolliyo’s live editor.

What happened?

• WarehouseStockAdapter translates GetQty to FetchAvailable.
• Domain code depends on IStockClient only — legacy stays isolated.

Practice next

1. Call GetQty through the adapter.
2. Swap adapter to a fake returning 0 for tests.
3. Keep LegacyWarehouseSdk out of controllers.
4. Map sku to legacy code format inside adapter.
5. Throw a domain exception on legacy failures.

Remember

Wrap foreign APIs. Expose your interface. Keep legacy at the edge.

ShopNest warehouse adapter

Checkout reserves stock via IStockClient.

Outcome: SOAP SDK can be replaced later without touching OrderService.