S90-09A · Question #2
Service A is an entity service with a functional context dedicated to invoice-related processing. Service B is a utility service that provides generic data access to a database. In this service…
The correct answer is C. The Standardized Service Contract principle can be applied to the service contract of Service A so. Applying the Standardized Service Contract principle to Service A means redesigning its contract at design time to accept XML Schema A (the same schema used by both Service Consumer A and Service B), which resolves the incompatibility without introducing any new runtime…
Question
Service A is an entity service with a functional context dedicated to invoice-related processing. Service B is a utility service that provides generic data access to a database. In this service composition architecture, Service Consumer A sends a SOAP message containing an invoice XML document to Service A(1). Service A then sends the invoice XML document to Service B (2), which then writes the invoice document to a database. The data model used by Service Consumer A to represent the invoice document is based on XML Schema A. The service contract of Service A is designed to accept invoice documents based on XML Schema B. The service contract for Service B is designed to accept invoice documents based on XML Schema A. The database to which Service B needs to write the invoice record only accepts entire business documents in Comma Separated Value (CSV) format. Due to the incompatibility of XML schemas used by the services, the sending of the invoice document from Service Consumer A through to Service B cannot be accomplished using the services as they currently exist. Assuming that the Contract Centralization and Logic Centralization patterns are being applied, what steps can be taken to enable the sending of the invoice document from Service Consumer A to the database without adding logic that will increase the runtime performance of the service composition?
Exhibit
Options
- AThe Data Model Transformation pattern can be applied so that the invoice document sent by
- BThe service composition can be redesigned so that Service Consumer A sends the invoice
- CThe Standardized Service Contract principle can be applied to the service contract of Service A so
- DNone of the above.
How the community answered
(56 responses)- A9% (5)
- B18% (10)
- C68% (38)
- D5% (3)
Explanation
Applying the Standardized Service Contract principle to Service A means redesigning its contract at design time to accept XML Schema A (the same schema used by both Service Consumer A and Service B), which resolves the incompatibility without introducing any new runtime processing logic - no transformation occurs at execution time, so performance is unaffected. Option A is wrong because the Data Model Transformation pattern explicitly adds runtime transformation logic, directly contradicting the constraint against increasing runtime performance overhead. Option B is wrong because routing Service Consumer A directly to Service B would violate the Logic Centralization pattern, which requires invoice-related business logic to remain centralized in Service A; bypassing Service A would fragment that logic. Option D is wrong because a valid solution exists in Option C.
Memory tip: Remember the contrast between design-time fixes vs. runtime fixes - when the question forbids adding runtime logic, your answer should fix the contract/schema alignment before messages flow, not transform them as they flow. "Standardize the contract, skip the transformation."
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