CRS-IUA basically builds on top of what CRS-M provides, and CRS-M builds on top of what Commerce Reference Store provides. This means that CRS-IUA is built on the entire server side structure that CRS-M provides, including the multisite setup, form handlers, droplets and so on -- what we do in the server part of CRS-IUA is expose those things through REST.

Module Dependencies

The root Commerce Reference Store module is the Store module that you see under <ATG10dir>/CommerceReferenceStore/Store when you first install the application. This establishes a hierarchy of module dependency between the root module and the mobile and IUA modules, as shown in the following figure:

Learning about Dependencies

The dependencies that any given module has are specified in its MANIFEST.MF file. For example, this is the manifest for Store.Mobile:

Manifest-Version: 1.0
Ant-Version: Apache Ant 1.7.0
Created-By: 20.1-b02-383 (Apple Inc.)
ATG-Product: Mobile Storefront Fashion Commerce
ATG-Client-Class-Path: lib/classes.jar
ATG-Class-Path: lib/classes.jar
ATG-Config-Path: config/config.jar
ATG-Required: Store.Storefront
Name: lib/classes.jar
ATG-Client-Update-File: true

This means that the Store.Mobile module is dependent on Store.Storefront, the Commerce Reference Store Storefront module.

In the manifest for Store.Mobile.REST we see:

Manifest-Version: 1.0
ATG-Client-Class-Path: lib/classes.jar
ATG-Class-Path: lib/classes.jar
ATG-Config-Path: config/config.jar
ATG-Required: @module_root_parent@.Mobile REST

Name: lib/classes.jar
ATG-Client-Update-File: true

This shows that Store.Mobile.REST is dependent the module's root parent's Mobile module, and is also dependent on REST, meaning the Store.Mobile and the ATG REST module.