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 the 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 pattern
is being applied and that the Logic Centralization is not 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 requirements of
the service composition?

• A. Service Consumer A can be redesigned to use XML Schema B so that the SOAP
  message it sends is compliant with the service contract of Service A . The Data Model
  Transformation pattern can then be applied to transform the SOAP message sent by
  Service A so that it conforms to the XML Schema A used by Service B.
  The Standardized Service Contract principle must then be applied to Service B and Service Consumer A so
  that the invoice XML document is optimized to avoid unnecessary validation.
• B. Service Consumer A can be redesigned to write the invoice document directly to the
  database. This reduces performance requirements by avoiding the involvement of Service
  A and Service B . It further supports the application of the Service Abstraction principle by
  ensuring that Service Consumer A hides the details of the data access logic required to
  write to the database.
• C. None of the above.
• D. The service composition can be redesigned so that Service Consumer A sends the
  invoice document directly to Service B.
  Because Service Consumer A and Service B use XML Schema A, the need for transformation logic is avoided. This naturally applies the
  Service Loose Coupling principle because Service Consumer A is not required to send the
  invoice document in a format that is compliant with the database used by Service B.

It has been confirmed that Policy A and Policy B are, in fact, the same policy and that the
security credential check performed by Service Agent B also needs to be carried out on
messages sent to Service B .

How can this service composition architecture be changed to reduce the redundancy of
policy content and fulfill the new security requirement?

• A. The Policy Centralization pattern can be applied so that Policy A and Policy B are
  combined into the same policy. The Service Agent pattern is then applied to introduce a
  new service agent (called Service Agent D) which carries out the validation and
  enforcement of Policy A and Policy B.
  Service Agent B can be moved so that it performs
  the security credential check for Service B, but not for Service A .
• B. The Policy Centralization pattern can be applied so that Policy A and Policy B are
  combined into the same policy. The policy enforcement logic is removed from Service
  Agent C and Service Agent A is then used to enforce the policy for messages sent to
  Service A and Service B . Service Agent B can be used to perform the security credential
  check for Service A and Service B .
• C. The Policy Centralization pattern can be applied so that Service Agent A is changed to
  enforce the policy for messages sent to Service A and Service B and to perform the
  security credential check for Service A and Service B .
• D. None of the above.

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
  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.
• B. 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.
• C. None of the above.
• D. 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.