Service Consumer a Sends a Message with a Business Document

question 19

Multiple Choice

Service Consumer A sends a message with a business document to Service A (1) , which writes the business document to Database A (2) . Service A then forwards the business document to Service B (3) , which writes the business document to Database B (4) . Service B then responds to Service A with a message containing a failure or success code (5) after which Service A responds to Service Consumer A with a message containing a failure or success code (6) . Upon receiving the message, Service Consumer A updates a log table in Database B (7) . The log entry is comprised of the entire business document. Database A is dedicated to the Service A service architecture and Database B is a shared database. There are two problems with this service composition architecture that you are asked to address: First, both Service Consumer A and Service B need to transform the business document data from an XML format to a proprietary Comma Separated Value (CSV) in order to write the data to Database B. This has led to redundant data format transformation logic that has been difficult to keep in synch when Database B changes. Secondly, Service A is an entity service that is being reused by several other service compositions. It has lately developed reliability problems that have caused the service to become unavailable for extended periods. What steps can be taken to solve these problems?

• A) The Legacy Wrapper pattern can be applied so that data access to Database B is separated into a new wrapper utility service. This way, the Data Format Transformation pattern only needs to be applied within the logic of this new service which will expose a standardized contract that both Service Consumer A and Service B can access. The Asynchronous Queuing pattern can be applied so that messaging queues are established between Service Consumer A and Service A and between Service A and Service B . The Service Autonomy principle can be further applied to Service A in order to establish a more isolated and reliable surrounding infrastructure.
• B) The Legacy Wrapper pattern can be applied so that data access to Database B is separated into a new wrapper utility service. This way, the Data Format Transformation pattern only needs to be applied within the logic of this new service which will expose a standardized contract that both Service Consumer A and Service B can access. The Reliable Messaging pattern can be applied so that acknowledgements are passed between Service Consumer A and Service A and between Service A and Service B . The Service Composability principle can be further applied to Service A in order to optimize its service architecture for improved participation in multiple service compositions.
• C) The service composition can be redesigned with the application of the Contract Centralization pattern so that instead of writing the business document to Database B, Service Consumer A sends the business document to Service B instead. This way, Service B would provide the only location where data format transformation logic for Database B needs to be carried out, which further supports the application of the Service Reusability principle. The Reliable Messaging pattern can be applied so that acknowledgements are passed between Service Consumer A and Service A and between Service A and Service B . The Service Composability principle can be further applied to Service A in order to optimize its service architecture for improved participation in multiple service compositions.
• D) None of the above.

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Definitions:

Financial Statements

Materials that present a snapshot of a business's financial health, detailing the balance sheet, income statement, and cash flow statement.

Common Voting Stock

Shares in a corporation that grant the holder the right to vote on corporate matters and potentially receive dividends.

Goodwill

An intangible asset that arises when a buyer acquires an existing business, representing the premium paid over the fair value of the net identifiable assets of the business.

Par Value

The nominal or face value of a stock or bond as stated by the issuing company, which may differ from its market value.