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The AIA Enterprise Business Services (EBS) represent the core business functions of an enterprise as they interact with the wider ecosystem of enterprises as part of day to day business interactions. They are not web services exposed by any business software application implemented in an enterprise.

Let me elaborate further. In any enterprise, we always find multitude of software applications implemented. This is mostly by design. Running a business is complicated and it is challenging to keep up with the competitors. In their quest to excel, enterprises seek best of the breed software applications evaluating their core functionalities. Thus an enterprise ends up with different software applications catering to Customer Management, Product Management, Asset Management, Order Management, Financial Management and so on. The stove pipes of applications are more narrower in scope, in reality.

The web services or APIs exposed by these software applications are granular in nature and represent their core functionalities. These applications need to be integrated in order for the enterprise to carry out the core business functions. For each of these business functions or tasks to be accomplished, multiple applications with their granular services need to participate.

The AIA Enterprise Business Services, representing these business functions or tasks, mediate the invocation of the granular web services between various participating applications.

Needless to say, the payloads of the AIA Enterprise Business Services are Enterprise Business Messages (EBM) and these represent the canonical data models of the industry in which the enterprise is doing business. They are not hostage to the participating application data models.

More on Enterprise Business Messages and Enterprise Business Objects (EBO) in next post.

The SOA Design Patterns site (and book) has an interesting chapter on the topic of schema centralization.  The recommended solution is essentially the pattern used in AIA.

1. Establish your service inventory using a top-down business process model driven approach.

2. Identify the Enterprise Business Objects (EBO) and Enterprise Business Messages (EBM). 

3. Create the EBO Schema canonical definitions using the industry standards.

4. Create the Enterprise Business Services (EBS) utilizing the EBMs created above.

The Case Study section in the end is empty, but AIA could very well be its best case study!

As an architect explaining SOA concepts to developers of traditional enterprise applications, I encountered various analogies comparing the concepts of SOA to Lego^TM blocks, which are actually considered by some experts as being misleading and superficial. Therefore, recent analogies by Antony Reynolds and Richard Veryard comparing services to a laundry, brought back memories of yet another analogy I used a couple of years ago - comparing business process driven SOA to home construction.

Let’s pretend you want to build a house from the ground up. You hire a general contractor, who is responsible for the overall execution of the project. The contractor locates a provider of concrete and makes a phone call to ask for estimates and the schedule for pouring the foundation slab. Next, the contractor will call and coordinate the lumber delivery, following which the framers can come out to do their job. In parallel, the contractor gets estimates from electricians and has to decide on the one that not only has the best rates, but also someone who is certified as per city code and who can meet the schedule. And finally, the roofers, plumbers and painters are arranged to complete the job.

Let’s put this in the perspective of SOA technologies. The general contractor is a BPEL Process, whose purpose is to orchestrate all the Services from disparate heterogeneous systems. The services in this example are the different actors – the concrete provider, foundation company, lumber company, framers, electricians, roofers, plumbers and painters. The contractor found the providers by searching the Yellow Pages (UDDI) and found the phone listing (WSDL); communicated by voice (XML) over the phone (standards based Web Service) in English (Standardized Semantics). He got quote and availability information, without having to really understand much about the inner workings of the concrete business (Service Abstraction), and as long as the provider abides by the contract, the contractor does not care who the actual electrician is (Service Virtualization).

I found that this metaphor helped many a legacy developer understand the complex SOA technologies better than the overly simplistic Lego^TM blocks analogy. However, as recommended in the other blogs too, it is best to not push the metaphor too far. Once the SOA basics have been understood, its purpose is served; and no other simplistic metaphor can then explain every one of the prolific WS-<insert your favorite noun here> specifications.

UPDATE 07/30/2008: Richard points out a sequel to his laundry post: Services Not All Like Laundry. And just when we thought we had it all sorted out :)

The Enterprise Business Messages are the packets of data which the Enterprise Business Services accept from requesters and route to providers. They carry the pieces of data needed for the requests to be understood and serviced. Needless to say, these are unique to the industry the enterprise is in business and their structures have evolved over time. As I said before, they are hostage to no application.

An application finds its way into an enterprise because of its unique ability to address specific business requirements. In the process of developing this ability, the application comes up with unique data structures.

The Enterprise Business Messages (along with the Enterprise Business Objects) empower the enterprises to evaluate the applications and transform the disparate data structures (and underlying concepts) of these 'best of the breed' applications into enterprise concepts driving their business processes.

Thus an Order Capture application would have Order entities to capture the order while a Billing application may have ability to enable billing in Customer entities for the services rendered. A service industry specific Sales Order EBM would have the structure to represent the Order captured for a Customer in Order Capture system and turn it into Customer in a Billing system with billing enabled for the services rendered.

In AIA, we talk about extensibility for Enterprise Business Objects, XSLTs, BPEL processes and also ESB Routing Rules.

But what about Enterprise Business Message and Enterprise Business Service?

Lets look at Enterprise Business Message first.

Since an Enterprise Business Message is assembly for schema components, extensibility would mean a new EBM. The solution is to create a new EBM xsd containing the required EBM definitions.

For example, lets say there is ItemEBM.xsd which has CreateItemEBM, UpdateItemEBM and QueryItemEBM. There is a need for DeleteItemEBM and ValidateItemEBM. To extend the ItemEBM.xsd, create a CustomItemEBM.xsd and include in it the definitions for DeleteItemEBM and ValidateItemEBM.

Similarly, extending Enterprise Business Service would mean adding new operations. This can be accomplished by creating an extension EBS (a new ESB routing service), for holding the customer specific operations. This newly created ESB routing service can either use the same EBM or the newly created EBM (for housing the Enterprise Business Messages for these new operations). Since these are newly created entities, they are totally upgrade safe.

So, ItemEBS continues to support the standard CRUD operations and is based on the shipped ItemEBS.wsdl. For a custom operation, you need to

• Create a new wsdl file CustomItemEBS.wsdl defining the interface / contract including the operations
• Create a new ESB project containing a routing service CustomItemEBS pointing to your new wsdl
• Deploy the CustomItemEBS

The Agile PLM to SAP: Design to Release PIP was released as part of the AIA Release Vehicle 2.3. More details can be found in this datasheet.

From an AIA perspective, this PIP only goes to prove the value proposition of the architecture. The PIP was built based on the existing Agile PLM to EBS PIP based on the best practice “Design to Release” process. There was >70% reuse of the services that was created for the E-Business Suite PIP. The remaining 30% were specific to E-Business Suite and not relevant for the SAP integration, and only those specific SAP connectors had to be built. It took a partner only four months development time to build out those connectors and deliver this integration.  This not only reduced the cost of developing this integration but drastically reduced the execution risk by reusing services and following the design patterns using the AIA reference architecture.