Arcitura Education S90.09 SOA Design & Architecture Lab Exam Practice Test

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Total 40 questions

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Question 1

Service A is a utility service that provides generic data access logic to a database that contains data that is periodically replicated from a shared database (1). Because the Standardized Service Contract principle was applied to the design of Service A, its service contract has been fully standardized. The service architecture of Service A is being accessed by three service consumers. Service Consumer A accesses a component that is part of the Service A implementation by invoking it directly (2). Service Consumer B invokes Service A by accessing its service contract (3). Service Consumer C directly accesses the replicated database that is part of the Service A implementation (4). You've been told that the shared database will soon be replaced with a new database product that will have new data models and new replication technology. How can the Service A architecture be changed to avoid negative impacts that may result from the replacement of the database and to establish a service architecture in which negative forms of coupling can be avoided in the future?

AThe Contract Centralization pattern can be applied to force all service consumers to access the Service A architecture via its published service contract. This will prevent negative forms of coupling that could lead to problems when the database is replaced. The Service Abstraction principle can then be applied to hide underlying service implementation details so that future service consumers cannot be designed to access any part of the underlying service implementation.

BThe Contract Centralization pattern can be applied to force Service Consumer C to access the Service A architecture via its published service contract. This will prevent Service Consumer A from being negatively impacted when the database is replaced in the future.

CThe Standardized Service Contract principle can be applied to force Service Consumer B to comply to the standardized service contract of Service A . As a result, the coupling between Service Consumer B and Service A is reduced. The Logic Centralization pattern can then be applied to position the logic provided by Service A as a primary access point for the database. As a result, the component within the Service A architecture abstracts the proprietary details of the database, thereby shielding Service Consumer A (and any future service consumers) from changes made to the database.

DNone of the above.

Answer : A

Question 2

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?

AThe 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.

BThe 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 Compos ability principle can be further applied to Service A in order to optimize its service architecture for improved participation in multiple service compositions.

CThe 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 Compos ability principle can be further applied to Service A in order to optimize its service architecture for improved participation in multiple service compositions.

DNone of the above.

Answer : A

Question 3

Service Consumer A sends Service A a message containing a business document (1). The business document is received by Component A, which keeps the business document in memory and forwards a copy to Component B (3). Component B first writes portions of the business document to Database A (4). Component B writes the entire business document to Database B and then uses some of the data values from the business document as query parameters to retrieve new data from Database B (5). Next, Component B returns the new data back to Component A (6), which merges it together with the original business document it has been keeping in memory and then writes the combined data to Database C (7). The Service A service capability invoked by Service Consumer A requires a synchronous request-response data exchange. Therefore, based on the outcome of the last database update, Service A returns a message with a success or failure code back to Service Consumer A (8). Databases A and B are shared and Database C is dedicated to the Service A service architecture.

There are several problems with this architecture: The business document that Component A is required to keep in memory (while it waits for Component B to complete its processing) can be very large. Especially when Service A is concurrently invoked by multiple service consumers, the amount of runtime resources it uses to keep this data in memory can decrease the overall performance of all service instances. Additionally, because Database A is a shared database that sometimes takes a long time to respond to Component B, Service A can take a long time to respond back to Service Consumer A . Currently, Service Consumer A will wait for a response for up to 30 seconds after which it will assume the request to Service A has failed and any subsequent response messages from Service A will be rejected. What steps can be taken to solve these problems?

AThe Service Statelessness principle can be applied together with the State Repository pattern in order to extend Database C so that it also becomes a state database allowing Component A to temporarily defer the business document data while it waits for a response from Component B . The Service Autonomy principle is applied together with the Legacy Wrapper pattern to isolate Database A so that it is encapsulated by a separate wrapper utility service. The Compensating Service Transaction pattern is applied so that if the response time of Service A exceeds 30 seconds, a notification is sent to a human administrator to raise awareness of the fact that the eventual response of Service A will be rejected by Service Consumer A .

BThe Service Statelessness principle can be applied together with the State Repository pattern in order to establish a state database that Component A can defer the business document data to while it waits for a response from Component B . The Service Autonomy principle can be applied together with the Service Data Replication pattern to establish a dedicated replicated database for Component B to access instead of the shared Database A . The Asynchronous Queuing pattern can be applied to establish a messaging queue between Service Consumer A and Service A so that Service Consumer A does not need to remain stateful while it waits for a response from Service A .

CThe Service Statelessness principle can be applied together with the State Repository pattern in order to establish a state database that Component A can defer the business document data to while it waits for a response from Component B . The Service Autonomy principle can be applied together with Service Abstraction principle, the Legacy Wrapper pattern, and the Service Facade pattern in order to isolate Database A so that it is encapsulated by a separate wrapper utility service and to hide the Database A implementation from Service A and to position a Facade component between Component B and the new wrapper service. This Facade component will be responsible for compensating the unpredictable behavior of Database A .

DNone of the above.

Answer : B

Question 4

You are told that in this service composition architecture, all four services are exchanging invoice related data in an XML format. The services in Service Inventory A are standardized to use a specific XML schema for invoice data. Design standards were not applied to the service contracts used in Service Inventory B, which means that each service uses a different XML schema for the same kind of data. Database A and Database B can only accept data in the Comma Separated Value (CSV) format and therefore cannot accept XML formatted data. What steps can be taken to enable the planned data exchange between these four services?

AThe Data Model Transformation pattern can be applied so that data model transformation logic is positioned between Service A and Service B, between Service A and Service C, and between Service C and Service D . The Data Format Transformation pattern can be applied so that data format transformation logic is positioned between the Service B logic and Database A and between the Service D logic and Database B .

BThe Data Model Transformation pattern can be applied so that data model transformation logic is positioned between Service A and Service C and between Service C and Service D . The Data Format Transformation pattern can be applied so that data format transformation logic is positioned between the Service B logic and Database A and between the Service D logic and Database B .

CThe Data Model Transformation pattern can be applied so that data model transformation logic is positioned between Service A and Service C . The Protocol Bridging pattern can be applied so that protocol bridging logic is positioned between Service A and Service B and between the Service C and Service D . The Data Format Transformation pattern can be applied so that data format transformation logic is positioned between the Service B logic and Database A and between the Service D logic and Database B .

DNone of the above.

Answer : A

Question 5

Service A is a task service that is required to carry out a series of updates to a set of databases in order to complete a task. To perform the database updates Service A must interact with three other services, each of which provides standardized data access capabilities. Service A sends its first update request message to Service B (1), which then responds with a message containing a success or failure code (2). Service A then sends its second update request message to Service C (3), which also responds with a message containing a success or failure code (4). Finally, Service A sends a request message to Service D (5), which responds with its own message containing a success or failure code (6).

You've been given a requirement that all database updates must either be completed successfully or not at all. This means that if any of the three response messages received by Service A contain a failure code, all of the updates carried out until that point must be reversed. Note that if Service A does not receive a response message back from Services B, C, or D, it must assume that a failure has occurred. How can this service composition architecture be changed to fulfill these requirements?

AThe Reliable Messaging pattern can be applied to guarantee the delivery of positive or negative acknowledgements. This way, Service A will always be informed of whether a failure condition has occurred with any of the database updates performed by Services B, C, and D . Furthermore, the Service Loose Coupling principle can be applied to ensure that the request and response messages exchanged by the services do not contain any implementation details that would indirectly couple Service A to any of the databases.

BThe Atomic Service Transaction pattern can be applied individually to Services B, C, and D so that each of these services performs its own database update within the scope of an atomic transaction. If anyone update fails, that change can be rolled back on that database. Furthermore, the Service Loose Coupling principle can be applied to ensure that Service A is kept out of the scope of the atomic transaction so that it is not negatively coupled to the proprietary database technologies that are required to enable the atomic transaction functionality.

CThe Compensating Service Transaction can be applied to Service A so that when any one response message containing a failure code is received by Service A, it can invoke exception handling logic that will log the failed database updates. The Service Loose Coupling principle can be further applied to ensure that Services B, C, or D are not indirectly coupled to the exception handling logic, especially if Service A requires additional access to Services B, C, or D in order to collect more information for logging purposes.

DNone of the above.

Answer : D

Question 6

Service Consumer A sends a message to Service A . There are currently three duplicate implementations of Service A (Implementation 1, Implementation 2, Implementation 3). The message sent by Service Consumer A is intercepted by Service Agent A (1), which determines at runtime which implementation of Service A to forward the message to. All three implementations of Service A reside on the same physical server.

You are told that after Service A was deployed, each of its three implementations was claimed by a different IT department, which means each implementation of Service A has a different owner. You are informed that a new service capability will soon need to be added to Service A . This service capability will introduce new business logic specific to Service A as well as logic required to access a shared database. What steps can be taken to ensure that the service owners will each add the service capability in a consistent manner to their respective implementations of Service A?

AThe Contract Centralization pattern can be applied so that when the new service capability is added, the Service A service contract will become the primary contact point for Service A . This will avoid Service Consumer A or any other potential service consumer from being designed to access the shared database directly. The Service Abstraction principle can be applied to further hide the implementation details so that Service Consumer A and other service consumers are unaware of the fact that the shared database is being accessed.

BThe Legacy Wrapper pattern can be applied to establish a new wrapper utility service that will provide standardized data access service capabilities for the shared database. This will avoid Service A from having to access the shared database directly and will further support the application of the Service Loose Coupling principle between Service A and the new utility service. By abstracting the data access logic into the wrapper service, there is no need to add the new service capability to each implementation of Service A .

CThe Standardized Service Contract principle is applied to ensure that the new service capability is consistently added to the service contract of each implementation and that it extends the existing Service A service contract in a manner that is compliant with current design standards. The Service Loose Coupling principle is applied to ensure that the new service capability remains decoupled from the underlying logic and implementation so that Service Consumer A does not become indirectly coupled to any new logic or to the shared database.

DNone of the above.

Answer : C

Question 7

Service A is an entity service that provides a Get capability that returns a data value that is frequently changed. Service Consumer A invokes Service A in order to request this data value (1). For Service A to carry out this request, it must invoke Service B (2), a utility service that interacts (3.4) with the database in which the data value is stored, Regardless of whether the data value changed. Service B returns the latest value to Service A (5), and Service A returns the latest value to Service Consumer A (6). The data value is changed when the legacy client program updates the database (7). When this change happens is not predictable. Note also that Service A and Service B are not always available at the same time. Any time the data value changes. Service Consumer A needs to receive it as soon as possible. Therefore, Service Consumer A initiates the message exchange shown in the Figure several times a day. When it receives the same data value as before, the response from Service A is ignored. When Service A provides an updated data value, Service Consumer A can process it to carry out its task.

Because Service A and Service B are not always available at the same times, messages are getting lost and several invocation attempts by Service Consumer A fail. What steps can be taken to solve this problem?

AThe Asynchronous Queuing pattern can be applied so that messaging queues are established between Service A and Service B and between Service Consumer A and Service A . This way, messages are never lost due to the unavailability of Service A or Service B .

BThe Asynchronous Queuing pattern can be applied so that a messaging queue is established between Service A and Service B . This way, messages are never lost due to the unavailability of Service A or Service B . The Service Agent pattern can be further applied to establish a service agent that makes a log entry and issues a notification when re-transmission attempts by the messaging queue exceeds a pre-determined quantity.

CThe Asynchronous Queuing pattern can be applied so that a messaging queue is established between Service Consumer A and Service A . This way, messages are never lost due to the unavailability of Service A or Service B .The Service Agent pattern can be further applied to establish a service agent that makes a log entry each time a runtime exception occurs.

DNone of the above.

Answer : A