Chapter 3 Service Endpoint Design

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Viewing your service implementation in terms of layers helps to:

  Clearly divide responsibilities

  Provide a common or single location for request processing (both pre  and 

post processing) logic in the interaction layer 

  Expose existing business logic as a Web service

To put this notion of a layered view in the proper context, let's look at an

example such as adventure builder's business process Web service scenario. In

this scenario, a partner travel agency uses adventure builder enterprise's Web

service to build a travel itinerary for its clients. Through the service interface it

exposes to these travel agencies, adventure builder enterprise receives business

documents (in XML format) containing all required details for travel itinerary

requests. Adventure builder uses its existing workflow systems to process and

satisfy these partner requests. The interaction layer of adventure builder's exposed

Web service interface validates these incoming business documents, then converts

the incoming XML documents to its internal format or maps document content to

Java objects. Once the conversion is finished, control passes to the workflow

mechanisms in the processing layer where travel requests are completed. The

interaction layer generates responses for completed travel requests, converts

responses to XML documents or other appropriate formats, and ensures that

responses are relayed to the partner agencies.

It is important to clarify the extent of the preprocessing performed at the inter 

action layer, since it differs from the JAX RPC runtime processing. Adventure

builder's interaction layer its exposed Web service interface applies service 

specific preprocessing to requests coming in to the service. This service specific

preprocessing is performed only if required by the service logic, and it includes

converting incoming XML documents to a suitable form or mapping the docu 

ment contents to Java objects. This mapping of incoming XML documents to

business objects is not the same as the JAX RPC runtime mapping between XML

documents and Java objects. Although the container performs the JAX RPC

runtime mapping for all requests and responses, the developer chooses the

mapping of incoming XML documents to business objects.

E

Although there are advantages, as noted previously, to viewing a service in 

terms of interaction and processing layers, a Web service may opt to merge 

these two layers into a single layer. There are times when multiple layers make