Deck 5: SOA Design & Architecture Lab (S90-09A)

Question 1

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?

A) The 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.
B) The 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 .
C) The 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.
D) None of the above.

Answer 1

C

Question 2

Service A has become increasingly difficult to maintain. Its core service logic has become bloated and convoluted because it has been updated numerous times during which additional functionality was added to interact with the database and the legacy system and to support interaction with Service Consumers A and B (via the two service contracts) as well as interaction directly with Service Consumer C. What steps can be taken to solve these problems and to prevent them from happening again in the future?

A) The Service Facade pattern can be applied to position a Facade component between the core service logic and the implementation resources (the database and the legacy system) and to also position a Facade component between the two service contracts and Service Consumers A and B. The Official Endpoint pattern can be applied to limit access to Service A to one of its two published service contracts. The Service Loose Coupling principle can be applied so that Service Consumer C does not negatively couple itself directly to the core service logic of Service A .
B) The Service Facade pattern can be applied to position a Facade component between the core service logic and the implementation resources (the database and the legacy system) and to position a façade component between the core service logic and the two service contracts. The Contract Centralization pattern can be applied to limit access to Service A to one of its two published service contracts. The Service Abstraction principle can be applied to hide the implementation details of Service A from service consumers.
C) The Service Façade pattern can be applied to position a Facade component between the core service logic and the two service contracts. The Contract Centralization pattern can be applied to limit access to Service A to one of its two published service contracts. The Service Loose Coupling principle can be applied so that Service Consumer C does not negatively couple itself directly to the core service logic of Service A .
D) None of the above.

Answer 2

B

Question 3

Our service inventory contains the following three services that provide invoice-related data access capabilities: Invoice, InvProc, and Proclnv. These services were created at different times by different project teams and were not required to comply to any design standards. Therefore each of these services has a different data model for representing invoice data. Currently each of these three services has one service consumer: Service Consumer A accesses the Invoice service(1). Service Consumer B (2) accesses the InvProc service, and Service Consumer C (3) accesses the Proclnv service. Each service consumer invokes a data access capability of an invoice-related service, requiring that service to interact with the shared accounting database that is used by all invoice-related services (4, 5, 6). Additionally, Service Consumer D was designed to access invoice data from the shared accounting database directly (7), (Within the context of this architecture. Service Consumer D is labeled as a service consumer because it is accessing a resource that is related to the illustrated service architectures.) Assuming that the Invoice service, InvProc service, and ProcInv service are part of the same service inventory, what steps would be required to fully apply the Official Endpoint pattern?

A) One of the invoice-related services needs to be chosen as the official service providing invoice data access capabilities. Service Consumers A, B, and C then need to be redesigned to only access the chosen invoice-related service. Because Service Consumer D does not rely on an invoice-related service, it is not affected by the Official Endpoint pattern and can continue to access the accounting database directly. The Service Abstraction principle can be further applied to hide the existence of the shared accounting database and other implementation details from current and future service consumers.
B) One of the invoice-related services needs to be chosen as the official service providing invoice data access capabilities. Service Consumers A, B, and C then need to be redesigned to only access the chosen invoice-related service. Service Consumer D also needs to be redesigned to not access the shared accounting database directly, but to also perform its data access by interacting with the official invoice-related service. The Service Abstraction principle can be further applied to hide the existence of the shared accounting database and other implementation details from current and future service consumers.
C) Because Service Consumers A, B, and C are already carrying out their data access via published contracts, they are not affected by the Official Endpoint pattern. Service Consumer D needs to be redesigned to not access the shared accounting database directly, but to perform its data access by interacting with the official invoice-related service. The Service Abstraction principle can be further applied to hide the existence of the shared accounting database and other implementation details from current and future service consumers.
D) None of the above.

Answer 3

B

Question 4

When Service A receives a message from Service Consumer A(1),the message is processed by Component A. This component first invokes Component B (2), which uses values from the message to query Database A in order to retrieve additional data. Component B then returns the additional data to Component A. Component A then invokes Component C (3), which interacts with the API of a legacy system to retrieve a new data value. Component C then returns the data value back to Component A. Next, Component A sends some of the data it has accumulated to Component D (4), which writes the data to a text file that is placed in a specific folder. Component D then waits until this file is imported into a different system via a regularly scheduled batch import. Upon completion of the import, Component D returns a success or failure code back to Component A. Component A finally sends a response to Service Consumer A (5) containing all of the data collected so far and Service Consumer A writes all of the data to Database B (6). Components A, B, C. and D belong to the Service A service architecture. Database A, the legacy system, and the file folders are shared resources within the IT enterprise. Service A is a task service that completes an entire business task on its own without having to compose other services. However, you have received many complaints about the reliability of Service A . Specifically, it has three problems. First, when Component B accesses Database A, it may not receive a response for several minutes when the database is being accessed by other applications in the IT enterprise. Secondly, the legacy system accessed by Component C frequently crashes and therefore becomes unavailable for extended periods of time. Third, for Component D to respond to Component A, it must first wait for the batch import of the files to occur. This can take several minutes during which Service Consumer A remains stateful and consumes excessive memory. What steps can be taken to address these three problems?

A) The Legacy Wrapper pattern can be applied so that Component B is separated to wrap the shared database, thereby allowing Component A to interact with this new service instead of directly interacting with the database. The Legacy Wrapper pattern can be applied again so that Component C is separated into a separate service that acts as a wrapper of the legacy system API. Component D can then be separated into a separate service and the Event-Driven Messaging pattern can be applied to establish a publisher-subscriber relationship between this new service and Component A and between Service A and Service Consumer A. The interaction between Service Consumer A and Component A is then redesigned so that Component A issues a message back to Service Consumer A when the event related to the batch import is triggered.
B) The Service Data Replication pattern can be applied so that Component B can access a replicated database instead of having to access the shared Database A directly. The Legacy Wrapper pattern can be applied so that Component C is separated into a separate service that acts as a wrapper of the legacy system API. Next, the Reliable Messaging pattern can be applied so that acknowledgements are issued from the new wrapper service to Component A, thereby enabling notifying Component A during times when the legacy system is unavailable. Finally, Component D is separated into a separate service and the Event-Driven Messaging pattern is applied to establish a publisher-subscriber relationship between this new service and Component A. The interaction between Service Consumer A and Component A is then redesigned so that Component A first interacts with Component B and the new wrapper service. Service A then issues a final message back to Service Consumer A.
C) The Service Data Replication pattern can be applied so that Component B can access a replicated database instead of having to access the shared Database A directly. The Legacy Wrapper pattern can be applied so that Component C is separated into a separate service that acts as a wrapper of the legacy system API. Next, the Asynchronous Queuing pattern can be applied so that a messaging queue is positioned between Component A and the new wrapper service, thereby enabling communication during times when the legacy system is unavailable. Finally, Component D is separated into a new service and the Event-Driven Messaging pattern is applied to establish a publisher-subscriber relationship between this service and Component A and between Service A and Service Consumer A. The interaction logic is redesigned as follows: Component A interacts with Component B, the new wrapper service, and then issues a request to the new event-driven service. Upon receiving a response triggered by the event related to the batch import, Service A responds to Service Consumer A.
D) None of the above.

Question 5

Service A is a task service that sends Service B a message (2) requesting that Service B return data back to Service A in a response message (3). Depending on the response received. Service A may be required to send a message to Service C (4) for which it requires no response. Before it contacts Service B, Service A must first retrieve a list of code values from its own database (1) and then place this data into its own memory. If it turns out that it must send a message to Service C, then Service A must combine the data it receives from Service B with the data from the code value list in order to create the message it sends to Service C. If Service A is not required to invoke Service C, it can complete its task by discarding the code values. Service A and Service C reside in Service Inventory A. Service B resides in Service Inventory B. You are told that the services in Service Inventory A were designed with service contracts based on different design standards than the services in Service Inventory B. As a result, Service A and Service B use different data models to represent the data they need to exchange. Therefore, Service A and Service B cannot currently communicate. Furthermore, Service C is an agnostic service that is heavily accessed by many concurrent service consumers. Service C frequently reaches its usage thresholds during which it is not available and messages sent to it are not received. How can this service composition architecture be changed to avoid these problems?

A) The Data Model Transformation pattern can be applied by establishing an intermediate processing layer between Service A and Service B that can transform a message from one data model to another at runtime. The Intermediate Routing and Service Agent patterns can be applied so that when Service B sends a response message, a service agent can intercept the message and, based on its contents, either forward the message to Service A or route the message to Service C . The Service Autonomy principle can be further applied to Service C together with the Redundant Implementation pattern to help establish a more reliable and scalable service architecture.
B) The Data Model Transformation pattern can be applied by establishing an intermediate processing layer between Service A and Service B that can transform a message from one data model to another at runtime. The Asynchronous Queuing pattern can be applied to establish an intermediate queue between Service A and Service C so that when Service A needs to send a message to Service C, the queue will store the message and retransmit it to Service C until it is successfully delivered. The Service Autonomy principle can be further applied to Service C together with the Redundant Implementation pattern to help establish a more reliable and scalable service architecture.
C) The Data Model Transformation pattern can be applied by establishing an intermediate processing layer between Service A and Service B that can transform a message from one data model to another at runtime. The Intermediate Routing and Service Agent patterns can be applied so that when Service B sends a response message, a service agent can intercept the message and, based on its contents, either forward the message to Service A or route the message to Service C . The Service Statelessness principle can be applied with the help of the State Repository pattern so that Service A can write the code value data to a state database while it is waiting for Service B to respond.
D) None of the above.

Question 6

The architecture for Service A displayed in the Figure shows how the core logic of Service A has expanded over time to connect to a database and a proprietary legacy system (1) and to support two separate service contracts (2) that are accessed by different service consumers. The service contracts are fully decoupled from the service logic. The service logic is therefore coupled to the service contracts and to the underlying implementation resources (the database and the legacy system). Service A currently has three service consumers. Service Consumer A and Service Consumer B access Service A's two service contracts (3, 4). Service Consumer C bypasses the service contracts and accesses the service logic directly (5). You are told that the database and legacy system that are currently being used by Service A are being replaced with different products. The two service contracts are completely decoupled from the core service logic, but there is still a concern that the introduction of the new products will cause the core service logic to behave differently than before. What steps can be taken to change the Service A architecture in preparation for the introduction of the new products so that the impact on Service Consumers A, B, and C is minimized?

A) The Service Abstraction principle can be applied to hide the implementation details from the core service logic of Service A, thereby shielding this logic from changes to the implementation. In support of this, the Service Facade pattern can be applied to position Facade components between the core service logic and Service Consumers A and B. These Facade components will be designed to regulate the behavior of Service A . The Contract Centralization pattern can be applied to force Service Consumer C to access Service A via one of its existing service contracts.
B) A third service contract can be added together with the application of the Contract Centralization pattern. This will force Service Consumer C to access Service A via the new service contract. The Service Facade pattern can be applied to position a Facade component between the new service contract and Service Consumer C in order to regulate the behavior of Service A . The Service Abstraction principle can be applied to hide the implementation details of Service A so that no future service consumers are designed to access any of Service A's underlying resources directly.
C) The Service Facade pattern can be applied to position Facade components between the core service logic and the two service contracts. These Facade components will be designed to regulate the behavior of Service A . The Contract Centralization pattern can also be applied to force Service Consumer C to access Service A via one of its existing service contracts.
D) None of the above.

Question 7

Service A is an entity service that provides a set of generic and reusable service capabilities. In order to carry out the functionality of any one of its service capabilities, Service A is required to compose Service B (1) and Service C (2) and Service A is required to access Database A (3), Database B (4), and Database C (5). These three databases are shared by other applications within the IT enterprise. All of service capabilities provided by Service A are synchronous, which means that for each request a service consumer makes. Service A is required to issue a response message after all of the processing has completed. Depending on the nature of the service consumer request, Service A may be required to hold data it receives in memory until its underlying processing completes. This includes data it may receive from either Service A or Service B or from any of the three shared databases. Service A is one of many entity services that reside in a highly normalized service inventory. Because Service A provides agnostic logic, it is heavily reused and is currently part of many service compositions. You are told that Service A has recently become unstable and unreliable and several of the service consumers that access it have had to raise runtime exceptions due to these problems. What steps can be taken to solve these problems without compromising the normalization of the service inventory?

A) The Service Autonomy principle can be applied to increase the physical isolation of Service A and to reduce dependencies Service A has on external resources. In support of this, the Service Data Replication pattern can be applied in order to establish a dedicated database that contains replicated data from shared Databases A, B, and C . Furthermore, the Redundant Implementation pattern can be applied so that the logic Service A requires from Services B and C can be redundantly placed inside of Service A . This way, Service A avoids having to separately compose Services B and C
B) The Service Statelessness principle can be applied with the help of the State Repository pattern in order to establish a state database that Service A can use to defer state data it may be required to hold for extended periods. The Service Autonomy principle can also be applied in order to increase the physical isolation of Service A and to reduce dependencies Service A has on external resources. In support of this, the Service Data Replication pattern can be applied in order to establish a dedicated database that contains replicated data from shared Databases A, B, and C.
C) The Service Loose Coupling and Standardized Service Contract principles can be applied by introducing a separate utility service that provides centralized data access to the Databases A, B, and C, and exposes a standardized service contract that can be used by Service A . This will prevent Service A from direct dependencies on the shared databases in case any of them are replaced in the future. By following this approach, the Legacy Wrapper pattern is effectively applied via the introduction of the new utility service.
D) None of the above.

Question 8

Our service inventory contains the following three services that provide invoice-related data access capabilities: Invoice, InvProc, and Proclnv. These services were created at different times by different project teams and were not required to comply to any design standards. Therefore each of these services has a different data model for representing invoice data. Currently each of these three services has one service consumer: Service Consumer A accesses the Invoice service(1). Service Consumer B (2) accesses the InvProc service, and Service Consumer C (3) accesses the Proclnv service. Each service consumer invokes a data access capability of an invoice-related service, requiring that service to interact with the shared accounting database that is used by all invoice-related services (4, 5, 6). Additionally, Service Consumer D was designed to access invoice data from the shared accounting database directly (7). (Within the context of this architecture. Service Consumer D is labeled as a service consumer because it is accessing a resource that is related to the illustrated service architectures.) A project team recently proclaimed that it has successfully applied the Contract Centralization pattern to the service inventory in which the Invoice service, InvProc service, and ProcInv service reside. Upon reviewing the previously described architecture you have doubts that this is true. After voicing your doubts to a manager, you are asked to provide specific evidence as to why the Contract Centralization is not currently fully applied. Which of the following statements provides this evidence?

A) The Contract Centralization pattern is not fully applied to the Invoice, InvProc, and ProcInv services because they are being accessed by different service consumers and because they have redundant logic that introduces denormalization into the service inventory.
B) The Contract Centralization pattern is not fully applied because Service Consumer D is accessing the shared accounting database directly.
C) The Contract Centralization pattern is not fully applied because none of the invoice-related services are carrying out data access logic via a centralized and standardized invoice service. This is primarily because the Standardized Service Contract principle was not consistently applied during the delivery processes of the individual services.
D) None of the above.

Question 9

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 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 .
B) 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 .
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.

Question 10

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?

A) The 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.
B) The 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.
C) The 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.
D) None of the above.

Question 11

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?

A) The 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.
B) The 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.
C) The 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.
D) None of the above.

Question 12

Service A is a task service that sends Service B a message (2) requesting that Service B return data back to Service A in a response message (3). Depending on the response received. Service A may be required to send a message to Service C (4) for which it requires no response. Before it contacts Service B, Service A must first retrieve a list of code values from its own database (1) and then place this data into its own memory. If it turns out that it must send a message to Service C, then Service A must combine the data it receives from Service B with the data from the code value list in order to create the message it sends to Service C. If Service A is not required to invoke Service C, it can complete its task by discarding the code values. Service A and Service C reside in Service Inventory A. Service B resides in Service Inventory B. You are told that the services in Service Inventory A are all SOAP-based Web services designed to exchange SOAP 1.1 messages and the services in Service Inventory B are SOAP-based Web services designed to exchange SOAP 1.2 messages. Therefore, Service A and Service B cannot currently communicate. Furthermore, you are told that Service B needs to access a shared database in order to retrieve the data required by Service A. The response time of the database can sometimes be lengthy, which would cause Service A to consume too much resources while it is waiting and keeping the code values in memory. How can this service composition architecture be changed to avoid these problems?

A) The Protocol Bridging pattern can be applied by establishing an intermediate processing layer between Service A and Service B that can convert SOAP 1.1 messages to SOAP 1.2 messages and vice versa. The Service Data Replication pattern can be applied to Service B so that it is given a dedicated database with its own copy of the data it needs to access. The Service Normalization pattern can then be applied to ensure that the data within the replicated database is normalized with the shared database it is receiving replicated data from.
B) The Protocol Bridging pattern can be applied by establishing an intermediate processing layer between Service A and Service B that can convert SOAP 1.1 messages to SOAP 1.2 messages and vice versa. The Service Statelessness principle can be applied with the help of the State Repository pattern so that Service A can write the code value data to a state database while it is waiting for Service B to respond.
C) The Protocol Bridging pattern can be applied by establishing an intermediate processing layer between Service A and Service B that can convert SOAP 1.1 messages to SOAP 1.2 messages and vice versa. The Intermediate Routing pattern can be applied to dynamically determine whether Service A should send a message to Service C. The Service Autonomy principle can be applied to Service A to further increase its behavioral predictability by reducing the amount of memory it is required to consume.
D) None of the above.

Question 13

When Service A receives a message from Service Consumer A(1),the message is processed by Component A. This component first invokes Component B (2), which uses values from the message to query Database A in order to retrieve additional data. Component B then returns the additional data to Component A. Component A then invokes Component C (3), which interacts with the API of a legacy system to retrieve a new data value. Component C then returns the data value back to Component A. Next, Component A sends some of the data it has accumulated to Component D (4), which writes the data to a te>X file that is placed in a specific folder. Component D then waits until this file is imported into a different system via a regularly scheduled batch import. Upon completion of the import, Component D returns a success or failure code back to Component A. Component A finally sends a response to Service Consumer A (5) containing all of the data collected so far and Service Consumer A writes all of the data to Database B (6). Components A, B, C. and D belong to the Service A service architecture. Database A, the legacy system, and the file folders are shared resources within the IT enterprise. Service A is an entity service with a service architecture that has grown over the past few years. As a result of a service inventory-wide redesign project, you are asked to revisit the Service A service architecture in order to separate the logic provided by Components B, C, and D into three different utility services without disrupting the behavior of Service A as it relates to Service Consumer A . What steps can be taken to fulfill these requirements?

A) The Legacy Wrapper pattern can be applied so that Component B is separated into a separate wrapper utility service that wraps the shared database. The Asynchronous Queuing pattern can be applied so that a messaging queue is positioned between Component A and Component C, thereby enabling communication during times when the legacy system may be unavailable or heavily accessed by other parts of the IT enterprise. The Service Facade pattern can be applied so that a Facade component is added between Component A and Component D so that any change in behavior can be compensated. The Service Autonomy principle can be further applied to Service A to help make up for any performance loss that may result from splitting the component into a separate wrapper utility service.
B) The Legacy Wrapper pattern can be applied so that Component B is separated into a separate utility service that wraps the shared database. The Legacy Wrapper pattern can be applied again so that Component C is separated into a separate utility service that acts as a wrapper for the legacy system API. The Legacy Wrapper pattern can be applied once more to Component D so that it is separated into another utility service that provides standardized access to the file folder. The Service Facade pattern can be applied so that three Facade components are added: one between Component A and each of the new wrapper utility services. This way, the Facade components can compensate for any change in behavior that may occur as a result of the separation. The Service Composability principle can be further applied to Service A and the three new wrapper utility services so that all four services are optimized for participation in the new service composition. This will help make up for any performance loss that may result from splitting the three components into separate services.
C) The Legacy Wrapper pattern can be applied so that Component B is separated into a separate utility service that wraps the shared database. The Legacy Wrapper pattern can be applied again so that Component C is separated into a separate utility service that acts as a wrapper for the legacy system API. Component D is separated into a separate service and the Event-Driven Messaging pattern is applied to establish a publisher-subscriber relationship between this new service and Component A. The interaction between Service Consumer A and Component A is then redesigned so that Component A first interacts with Component B and the new wrapper service. Service A then issues a final message back to Service Consumer A. The Service Composability principle can be further applied to Service A and the three new wrapper utility services so that all four services are optimized for participation in the new service composition. This will help make up for any performance loss that may result from splitting the three components into separate services.
D) None of the above.

Question 14

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. 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 reason Service Consumers A and C bypass the published Service A service contract is because, for security reasons, they are not allowed to access a subset of the operations in the WSDL definition that expresses the service contract. How can the Service A architecture be changed to enforce these security restrictions while avoiding negative forms of coupling?

A) The 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 architecture details so that future service consumers cannot be designed to access any part of the underlying service implementation.
B) The Contract Centralization pattern can be applied to force service consumers to access the Service A architecture via its published service contract only. The Service Loose Coupling principle can then be applied to ensure that the centralized service contract does not contain any content that is dependent on or derived from the underlying service implementation.
C) The Concurrent Contracts pattern can be applied to Service A in order to establish one or more alternative service contracts. This allows service consumers with different levels of security clearance to continue accessing the service logic via its published service contracts.
D) None of the above.

Question 15

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?

A) The 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.
B) The 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.
C) The 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.
D) None of the above.

Question 16

Service A is an entity service that provides a set of generic and reusable service capabilities. In order to carry out the functionality of any one of its service capabilities, Service A is required to compose Service B (1) and Service C (2) and Service A is required to access Database A (3), Database B (4), and Database C (5). These three databases are shared by other applications within the IT enterprise. All of service capabilities provided by Service A are synchronous, which means that for each request a service consumer makes. Service A is required to issue a response message after all of the processing has completed. Depending on the nature of the service consumer request, Service A may be required to hold data it receives in memory until its underlying processing completes. This includes data it may receive from either Service A or Service B or from any of the three shared databases. Service A is one of many entity services that reside in a highly normalized service inventory. Because Service A provides agnostic logic, it is heavily reused and is currently part of many service compositions. You are told that Service A has recently become unstable and unreliable. The problem has been traced to two issues with the current service architecture. First, Service B, which is also an entity service, is being increasingly reused and has itself become unstable and unreliable. When Service B fails, the failure is carried over to Service A . Secondly, shared Database B has a complex data model. Some of the queries issued by Service A to shared Database B can take a very long time to complete. What steps can be taken to solve these problems without compromising the normalization of the service inventory?

A) The Redundant Implementation pattern can be applied to Service A, thereby making duplicate deployments of the service available. This way, when one implementation of Service A is too busy, another implementation can be accessed by service consumers instead. The Service Data Replication pattern can be applied to establish a dedicated database that contains an exact copy of the data from shared Database B that is required by Service A .
B) The Redundant Implementation pattern can be applied to Service B, thereby making duplicate deployments of the service available. This way, when one implementation of Service B is too busy, another implementation can be accessed by Service A instead. The Service Data Replication pattern can be applied to establish a dedicated database that contains an exact copy of the data from shared Database B that is required by Service A .
C) The Redundant Implementation pattern can be applied to Service B, thereby making duplicate deployments of the service available. This way, when one implementation of Service B is too busy, another implementation can be accessed by Service A instead. The Service Data Replication pattern can be applied to establish a dedicated database that contains a copy of the data from shared Database B that is required by Service A . The replicated database is designed with an optimized data model in order to improve query execution performance.
D) None of the above.

Question 17

Services A, B, and C are non-agnostic task services. Service A and Service B use the same shared state database to defer their state data at runtime. An assessment of these three services reveals that each contains some agnostic logic, but because it is bundled together with the non-agnostic logic, the agnostic logic cannot be made available for reuse. The assessment also determines that because Service A and Service B and the shared state database are each located in physically separate environments, the remote communication required for Service A and Service B to interact with the shared state database is causing an unreasonable decrease in runtime performance. You are asked to redesign this architecture in order to increase the opportunity for agnostic service logic to be reused and in order to decrease the runtime processing demands so that performance can be improved. What steps can be taken to achieve these goals?

A) The Enterprise Service Bus pattern can be applied to establish an environment whereby the Process Abstraction and Process Centralization patterns are naturally applied, resulting in a clean separation of non-agnostic task services from newly designed agnostic services that are further shaped into reusable services by the application of the Service Reusability principle.
B) The Process Centralization pattern can be applied, resulting in a redesign effort where agnostic logic is removed from the three task services so that they only encapsulate non-agnostic logic. The agnostic logic is then moved to one or more new agnostic services that are shaped into reusable services by the application of the Service Reusability principle. The Process Abstraction pattern is then applied to the redesigned task services Service A and Service B, so that their logic is physically centralized, turning them into orchestrated task services.
C) The Process Abstraction pattern can be applied, resulting in a redesign effort where agnostic logic is removed from the three task services so that they only encapsulate non-agnostic logic. The agnostic logic is then moved to one or more new agnostic services that are shaped into reusable services by the application of the Service Reusability principle. The Orchestration pattern can be further applied to establish an environment whereby the Process Centralization pattern is naturally applied to Services A and B and the State Repository pattern in naturally applied to further help avoid remote communication by providing a local and centralized state database that can be shared by both services.
D) None of the above.

Question 18

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 asked to change this service composition architecture in order to fulfill a set of new requirements: First, if the database update performed by Service B fails, then it must be logged by Service A. Secondly, if the database update performed by Service C fails, then a notification e-mail must be sent out to a human administrator. Third, if the database update performed by either Service C or Service D fails, then both of these updates must be reversed so that the respective databases are restored back to their original states. What steps can be taken to fulfill these requirements?

A) Service A is updated to perform a logging routine when Service A receives a response message from Service B containing a failure code. Service A is further updated to send an e-mail notification to a human administrator if Service A receives a response message from Service C containing a failure code. The Atomic Service Transaction pattern is applied so that Services A, C, and D are encompassed in the scope of a transaction that will guarantee that if the database updates performed by either Service C or Service D fails, then both updates will be rolled back.
B) The Compensating Service Transaction pattern is applied to Service B so that it invokes exception handling logic that logs failed database updates before responding with a failure code back to Service A . Similarly, the Compensating Service Transaction pattern is applied to Service C so that it issues an e-mail notification to a human administrator when a database update fails. The Atomic Service Transaction pattern is applied so that Services A, C, and D are encompassed in the scope of a transaction that will guarantee that if the database updates performed by either Service C or Service D fails, then both updates will be rolled back. The Service Autonomy principle is further applied to Service A to ensure that it remains consistently available to carry out this sequence of actions.
C) The Atomic Service Transaction pattern is applied so that Services A, C, and D are encompassed in the scope of a transaction that will guarantee that if the database updates performed by either Service C or Service D fails, then both updates will be rolled back. The Compensating Service Transaction pattern is then applied to all services so that the scope of the compensating transaction includes the scope of the atomic transaction. The compensating exception logic that is added to Service D automatically invokes Service B to log the failure condition and Service C to issue the e-mail notification to the human administrator. This way, it is guaranteed that the compensating logic is always executed together with the atomic transaction logic.
D) None of the above.

Question 19

Service Consumer A sends a message to Service A (1), which then forwards the message to Service B (2). Service B forwards the message to Service C (3), which finally forwards the message to Service D (4). Services A, B, and C each contain logic that reads the content of the message and, based on this content, determines which service to forward the message to. As a result, what is shown in the Figure is one of several possible runtime scenarios. You are told that the current service composition architecture is having performance problems because of two specific reasons. First, too many services need to be explicitly invoked in order for the message to arrive at its destination. Secondly, because each of the intermediary services is required to read the entire message contents in order to determine where to forward the message to, it is taking too long for the overall task to complete. What steps can be taken to solve these problems without sacrificing any of the functionality that currently exists?

A) The Intermediate Routing pattern can be applied together with the Service Agent pattern in order to establish a set of service agents capable of intercepting and forwarding the message based on pre-defined routing logic. To avoid the need for service agents to read the entire message contents, the Messaging Metadata pattern can be applied so that content relevant to the routing logic is placed in the header of a message. This way, only the message header content needs to be read by the service agents.
B) The Intermediate Routing pattern can be applied together with the Service Agent pattern in order to establish a set of service agents capable of intercepting and forwarding the message based on pre-defined routing logic. To avoid the need for service agents to read the entire message contents, the Rules Centralization pattern can be applied so that content relevant to the routing logic is isolated into a separate Rules service. This way, service agents are only required to access the Rules service in order to determine where to forward messages to. The Standardized Service Contract principle will need to be applied to ensure that the new Rules service and the new service agents provide service contracts that are compliant to existing design standards.
C) The Intermediate Routing pattern can be applied together with the Service Agent pattern in order to establish a set of service agents capable of intercepting and forwarding the message based on pre-defined routing logic. The Service Discoverability principle can be applied to improve the communications quality of message contents, which will reduce the time required by service agents to read the message contents at runtime.
D) None of the above.

Question 20

Service Consumer A sends a message to Service A. Before the message arrives with Service A, it is intercepted by Service Agent A (1). which checks the message for compliance to Policy A that is required by Service A. If the message fails compliance, Service Agent A will not allow it to proceed and will instead write the message contents to a log. If the message does comply to the policy, it continues to be transmitted toward Service A, but before it arrives it is intercepted by Service Agent B (2), which validates the security credentials in the message header. If the security credential validation fails, the message is rejected and a runtime exception is raised. If the security credentials are validated, the message is sent to Service A. Upon receiving the message, Service A retrieves a data value from a database and populates the message header with this data value (3) prior to forwarding the message to Service B. Before the message arrives at Service B. it is intercepted by Service Agent C (4) which checks the message for compliance with two policies: Policy B and Policy C. Policy B is identical to Policy A that was checked by Service Agent A. To check for compliance to Policy C. Service Agent C uses the data value added by Service A. If the message complies with both of the policies, it is forwarded to Service B (5), which stores the message contents in its own database. You are told that Policy B and Policy C have changed. Also, in order to carry out the compliance check of Policy C, Service Agent C will now require a new data value from the Service B database. How can this service composition architecture be changed to fulfill these new requirements?

A) The Policy Centralization pattern can be applied so that only one service agent is used to enforce Policy A and Policy B. Service A is redesigned to first query Service B for the value required by Service Agent C to check the compliance of the updated Policy C. If the compliance check is successful, the message is sent to Service B .
B) The Policy Centralization pattern can be applied so that only one service agent is used to enforce Policy A and Policy B. Service Consumer A is redesigned to first query Service B for the value required by Service Agent C. This way, Service Consumer A can include this value in the message header prior to sending the message to Service A .
C) The Policy Centralization pattern can be applied so that only one service agent is used to enforce Policy A and Policy B. The policy enforcement logic for Policy C is removed from Service Agent C and instead embedded within the logic of Service B . This way, Service B can itself retrieve the value required to check compliance with Policy C. If the message received is not in compliance, Service B will reject it.
D) None of the above.

Question 21

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.

Question 22

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. You are told that the database updates performed by Service A and Service B must be either both successful or they cannot happen at all. The database update performed by Service Consumer A must happen after it is given the outcome of the database updates performed by Service A and Service B . Given that Service Consumer A must also update Database B as part of this service composition architecture, how is it possible to fulfill these requirements?

A) The State Repository pattern can be applied so that Service A writes the business document data to a separate state database until it receives a response message from Service B . If the response message contains a success code, Service A writes the business document to Database A. If the response contains a failure code, Service A discards the data that was written to the state database.
B) The Service Data Replication pattern can be applied to Service Consumer A and Service B so that separate dedicated databases can be established allowing Service Consumer A to make updates independently of Service B . Service A is simply redesigned to not write the business document to Database A until after it receives a message containing a success code from Service B.
C) The Atomic Service Transaction pattern can be applied to encompass Service A, Service B and Service Consumer A. This will guarantee that all of the actions performed by the service composition participants will either be successful or will be rolled back if anyone is not successful.
D) None of the above.

Question 23

Service Consumer A invokes Service A (1). The logic within Service A is required to retrieve three independent data values from Services B, C, and D and to then return these data values back to Service Consumer A. To accomplish this, Service A begins by sending a request message to Service B (2). After receiving a response message with the first data value from Service B, Service A sends a request message to Service C (3). After it receives a response message with the second data value from Service C, Service A then sends a request message to Service D (4). Upon receiving a response message with the third data value from Service D. Service A finally sends its own response message (containing all three collected data values) back to Service Consumer A. Service Consumer A and Service A reside in Service Inventory A. Service B and Service C reside in Service Inventory B. Service D is a public service that can be openly accessed via the World Wide Web. The service is also available for purchase so that it can be deployed independently within IT enterprises. Due to the rigorous application of the Service Abstraction principle within Service Inventory B, the only information that is made available about Service B and Service C are the published service contracts. For Service D, the service contract plus a Service Level Agreement (SLA) are made available. The SLA indicates that Service D has a planned outage every night from 11 PM to midnight. You are an architect with a project team building services for Service Inventory A . You are told that the owners of Service Inventory A and Service Inventory B are not generally cooperative or communicative. Cross-inventory service composition is tolerated, but not directly supported. As a result, no SLAs for Service B and Service C are available and you have no knowledge about how available these services are. Based on the service contracts you can determine that the services in Service Inventory B use different data models and a different transport protocol than the services in Service Inventory A. Furthermore, recent testing results have shown that the performance of Service D is highly unpredictable due to the heavy amount of concurrent access it receives from service consumers from other organizations. You are also told that there is a concern about how long Service Consumer A will need to remain stateful while waiting for a response from Service A . What steps can be taken to solve these problems?

A) The Event-Driven Messaging pattern is applied so that a subscriber-publisher relationship is established between Service Consumer A and Service A . This gives Service A the flexibility to provide its response to Service Consumer A whenever it is able to collect the three data values without having to require that Service Consumer A remain stateful. The Asynchronous Queuing pattern is applied so that a central messaging queue is positioned between Service A and Service B and between Service A and Service C . The Data Model Transformation and Protocol Bridging patterns are applied to enable communication between Service A and Service B and between Service A and Service C . The Redundant Implementation pattern is applied so that a copy of Service D is brought in-house and made part of Service Inventory A.
B) The Asynchronous Queuing pattern is applied so that a central messaging queue is positioned between Service A and Service B and between Service A and Service C and so that a separate messaging queue is positioned between Service A and Service Consumer A. The Data Model Transformation and Protocol Bridging patterns are applied to enable communication between Service A and Service B and between Service A and Service C . The Redundant Implementation pattern is applied so that a copy of Service D is brought in-house for fail-over purposes. The Legacy Wrapper pattern is further applied to wrap Service D with a standardized service contract that is in compliance with the design standards used in Service Inventory A. This wrapper utility service first attempts to access the external service, but if that service is unavailable it will access the redundant internal service instead.
C) The Reliable Messaging pattern is applied so that a system of acknowledgements is established between Service Consumer A and Service A . This gives Service A the flexibility to provide Service Consumer A with acknowledgements that indicate that the processing steps that are occurring between Service A and Service B, Service C, and Service D are progressing. The Asynchronous Queuing pattern is applied so that a central messaging queue is positioned between Service A and Service B and between Service A and Service C and between Service A and Service D . The Data Model Transformation and Protocol Bridging patterns are applied to enable communication between Service A and Service B and between Service A and Service C .
D) None of the above.

Question 24

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: First, the response time of Database A is often poor, resulting in Component B taking too much time to provide a response to Component A. This results in Component A consuming too many runtime resources while it holds the business document in memory and it also causes unreasonable delays in responding to Service Consumer A. Additionally, Database B is being replaced with a different database product that supports a proprietary file format. This will disable the current interaction between Component B and the new Database B. What steps can be taken to solve these problems?

A) The State Repository pattern is applied so that Component A can defer the business document data to a state database while it waits for a response from Component B. The Service Data Replication pattern is applied so that Component B can interact with a database that is replicated from the shared Database A. This will improve performance and reliability that will affect both Component A and Service Consumer A. Finally, the Legacy Wrapper pattern is applied so that Database B is wrapped in a standardized contract. This will establish a new wrapper utility service that will allow Database B to be replaced with a different database product without affecting Service A . Furthermore, the Data Format Transformation pattern can be applied within the new wrapper utility service to enable it to convert to and from the new proprietary file format.
B) The State Repository pattern is applied so that Component A can defer the business document data to a state database while it waits for a response from Component B. The Asynchronous Queuing pattern can be applied so that a messaging queue is established between Service Consumer A and Service A, thereby guaranteeing delivery and avoiding Service Consumer A from being tied up too long waiting for Service A to respond. Finally, the Data Format Transformation pattern can be applied to enable Component B to convert to and from the new proprietary file format introduced by the database product that is replacing Database B.
C) The Legacy Wrapper pattern is applied so that Database B is wrapped in a standardized contract. This will establish a new wrapper utility service that will allow Database B to be replaced with a different database product without affecting Service A . The Data Format Transformation pattern can be applied within the new wrapper utility service to enable it to convert to and from the new proprietary file format. The Service Data Replication pattern is applied so that Component B can interact with a database that is replicated from the shared Database B, regardless of what database product is used to replace Database B. The Service Abstraction principle can be further applied to hide the implementation details, including the changes mentioned in this solution, from Service Consumer A.
D) None of the above.