S90.08B Dumps – Kickstart your Career with Real Updated Questions [Q10-Q33]

QUESTION 10
Refer to Exhibit.

The Client and Vendor services are agnostic services that are both currently part of multiple service compositions. As a result, these services are sometimes subjected to concurrent access by multiple service consumers.
The Client service primarily provides data access logic to a client database but also coordinates with other services to determine a clients credit rating. The Vendor service provides some data access logic but can also generate various dynamic reports based on specialized business requirements.
After reviewing historical statistics about the runtime activity of the two services, it is discovered that the Client service is serving an ever-increasing number of service consumers. It is regularly timing out, which in turn increases its call rate as service consumers retry their requests. The Vendor service occasionally has difficulty meeting its service-level agreement (SLA) and when this occurs, penalties are assessed.
Recently, the custodian of the Client service was notified that the Client service will be made available to new service consumers external to its service inventory. The Client service will be providing free credit rating scores to any service consumer that connects to the service via the Internet. The Vendor service will remain internal to the service inventory and will not be exposed to external access.
Which of the following statements describes a solution that addresses these issues and requirements?

The API Gateway pattern, together with the Inventory Endpoint pattern, can be applied to the service inventory to establish an inventory endpoint service and an intermediary layer of processing that will be accessed by external service consumers and that will interact with the Client service to process external service consumer requests. The Redundant Implementation pattern can be applied to both the Client and Vendor services to increase their availability and scalability.

The Official Endpoint pattern can be applied to the Client service to establish a managed endpoint for consumption by service consumers external to the service inventory. The Concurrent Contracts pattern can be applied to the Vendor service, enabling it to connect with alternative Client service implementation, should the first attempt to connect fail.

The State Repository pattern can be applied to the Client and Vendor services to establish a central statement management database that can be used to overcome runtime performance problems. The Official Endpoint pattern can be further applied to increase the availability and scalability of the Client service for service consumers external to the service inventory.

The Microservice Deployment pattern is applied to the Client service to improve its autonomy and responsiveness to a greater range of service consumers. The Containerization pattern is applied to the Vendor service to establish a managed environment with a high degree of isolation for its report-related processing. The Endpoint Redirection pattern is further applied to ensure that request messages from service consumers outside of the service inventory are redirected away from the Client service.

QUESTION 11

Service A is a utility service that provides generic data access logic to a database containing 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 partof 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 capabilities inthe API that comprises the Service A service contract. How can the Service A architecture be changed to enforce these security restrictions while avoiding negative forms of coupling?

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.

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.

The Contract Centralization pattern can be applied to force service consumers to access the Service A architecture via its published service contract only. 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 authorization to access different types of service logic via Service A’s published service contracts.

The Contract Centralization pattern can be applied to force service consumers to access the Service A architecture via its published service contract only. The Idempotent Capability pattern can be applied to Service A to establish alternative sets of service capabilities for service consumers with different levels of authorization.

QUESTION 12

Service A sends a message to Service B (1). After Service B writes the message contents to Database A (2), it issues a response message back to Service A (3). Service A then sends a message to Service C (4). Upon receiving this message, Service C sends a message to Service D (5), which then writes the message contents to Database B (6) and issues a response message back to Service C (7).
Service A and Service D are located in Service Inventory A. Service B and Service C are located in Service Inventory B.
You are told that In this service composition architecture, all four services are exchanging invoice-related data in an XML format. However, the services in Service Inventory A are standardized to use a different XML schema for invoice data than the services in Service Inventory B. Also, Database A can only accept data in the Comma Separated Value (CSV) format and therefore cannot accept XML-formatted data. Database B only accepts XML-formatted data. However, it is a legacy database that uses a proprietary XML schema to represent invoice data that is different from the XML schema used by services in Service Inventory A or Service Inventory B.
What steps can be taken to enable the planned data exchange between these four services?

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

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

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

The Protocol Bridging pattern can be applied so that protocol conversion 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

QUESTION 13

Service A, Service B, and Service Care entity services, each designed to access the same shared legacy system.
Service A manages order entities, Service B manages invoice entities, and Service C manages customer entities. Service A, Service B, and Service C are REST services and are frequently reused by different service compositions. The legacy system uses a proprietary file format that Services A, B, and C need to convert to and from.
You are told that compositions involving Service A, Service B, and Service C are unnecessarily complicated due to the fact that order, invoice, and customer entitles are all related to each other. For example, an order has a customer, an invoice has an order, and so on. This results In calls to multiple services to reconstruct a complete order document. You are asked to architect a solution that will simplify the composition logic by minimizing the number of services required to support simple businessfunctions like order management or bill payment. Additionally, you are asked to reduce the amount of redundant data transformation logic that is found in Services A, B, and C.
How will you accomplish these goals?

The Enterprise Service Bus pattern can be applied to introduce an intermediate processing layer between Services A, B, and C and the legacy system. The enterprise service bus can be used to consolidate and execute the necessary transformation logic currently held within the services. The Endpoint Redirection pattern can be applied to re-route calls from one service to another to provide access to related entity data.

The Legacy Wrapper pattern can be applied to create a service to expose the legacy system through a standardized service contract. The core logic of the wrapping service would provide all necessary data transformation functionality to convert between inventory-standardized data representations and the proprietary format. The Lightweight Endpoint pattern can be applied to establish lightweight capabilities that can return related entity data directly to service consumers.

The Enterprise Service Bus pattern can be applied to introduce an intermediate processing layer between Services A, B, and C and the legacy system. The enterprise service bus can be used to consolidate and execute the transformation logic currently held within the services. The Content Negotiation pattern can be applied to return a content link to related entity data to a service consumer, which allows for simpler and more dynamic composition logic. The service consumer effectively invokes the relevant service through the returned link to obtain the related entity data.

The Legacy Wrapper pattern can be applied to create a service to expose the legacy system through a standardized service contract. The core logic of the wrapping service would provide all necessary data transformation functionality to convert between inventory-standardized data representations and the proprietary format. The Endpoint Redirection pattern can be applied to return a link to related entity data to a service consumer, which allows for simpler and more dynamic composition logic. The service consumer effectively invokes the relevant service through the returned link to obtain the related entity data.

QUESTION 14

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.
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?

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 Replicationpattern 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.

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 Data Model Transformation 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.

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 to improve query execution performance.

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 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, thereby improving its availability and scalability.

QUESTION 15
Refer to Exhibit.

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 the three services reveals that each contains some agnostic logic that cannot be made available for reuse because it is bundled together with non-agnostic logic.
The assessment also determines that because Service A, 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.
How can the application of the Orchestration pattern improve this architecture?

The application of the Orchestration pattern will result in an environment whereby the Official Endpoint, State Repository, and Service Data Replication patterns are automatically applied, allowing the shared state database to be replicated via official service endpoints for Services A and B so that each task service can have its own dedicated state database.

The application of the Orchestration pattern will result in an environment whereby the non-agnostic logic can be cleanly separated from the agnostic logic that exists in Services A, B, and C, resulting in the need to design new agnostic services with reuse potential assured through the application of the Service Reusability principle. The State Repository pattern, which is supported by and local to the orchestration environment, provides a central state database that can be shared by Services A and B. The local state database avoids problems with remote communication.

The application of the Orchestration pattern will result in an environment whereby the Compensating Service Transaction is automatically applied, resulting In the opportunity to create sophisticated exception logic that can be used to compensate for the performance problems caused by Services A and B having to remotely access the state database. The API Gateway and Service Broker patterns are also automatically applied, providing common transformation functions in a centralized processing layer to help overcome any disparity in the service contracts that will need to be created for the new agnostic services.

The Orchestration pattern is not applicable to this architecture because it does not support the hosting of the required state repository.

QUESTION 16

Service A is an entity service that provides a Get capability which 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 will occur 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.
The current service composition architecture is using up too many resources due to the repeated invocation of Service A by Service Consumer A and the resulting message exchanges that occur with each invocation.
What steps can be taken to solve this problem?

The Event-Driven Messaging pattern can be applied by establishing a subscriber-publisher relationship between Service A and Service B. This way, every time the data value is updated, an event is triggered and Service B, acting as the publisher, can notify Service A, which acts as the subscriber. The Asynchronous Queuing pattern can be applied between Service A and Service B so that the event notification message sent out by Service B will be received by Service A, even when Service A is unavailable.

The Event-Driven Messaging pattern can be applied by establishing a subscriber-publisher relationship between Service Consumer A and Service A. This way, every time the data value is updated, an event is triggered and Service A, acting as the publisher, can notify Service Consumer A, which acts as the subscriber. The Asynchronous Queuing pattern can be applied between Service Consumer A and Service A so that the event notification message sent out by Service A will be received by Service Consumer A, even when Service Consumer A is unavailable.

The 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.

The Event-Driven Messaging pattern can be applied by establishing a subscriber-publisher relationship between Service Consumer A and a database monitoring agent introduced through the application of the Service Agent pattern. The database monitoring agent monitors updates made by the legacy client to the database. This way, every time the data value is updated, an event is triggered and the database monitoring agent, acting as the publisher, can notify Service Consumer A, which acts as the subscriber.
The Asynchronous Queuing pattern can be applied between Service Consumer A and the database monitoring agent so that the event notification message sent out by the database monitoring agent will be received by Service Consumer A, even when Service Consumer A is unavailable.

QUESTION 17

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).
However, Services A, B and C each contain logic that reads the contents of the message to determine what intermediate processing to perform and which service to forward the message to. As a result, what is shown in the diagram is only one of several possible runtime scenarios.
Currently, this service composition architecture is performing adequately, despite the number of services that can be involved in the transmission of one message. However, you are told that new logic is being added to Service A that will require it to compose one other service to retrieve new data at runtime that Service A will need access to in order to determine where to forward the message to. The involvement of the additional service will make the service composition too large and slow.
What steps can be taken to improve the service composition architecture while still accommodating the new requirements and avoiding an increase in the amount of service composition members?

The Service Instance Routing pattern can be applied to introduce a Routing service to provide a centralized service to contain routing-related business rules. This new Routing service can be accessed by Service A and Service C so they can determine where to forward messages to at runtime. The Service Reusability principle can be further applied to ensure that the logic in all remaining services is designed to be multi-purpose and reusable.

The Asynchronous Queuing pattern can be applied together with a Routing service that is invoked by messages read from a messaging queue. This new Routing service can replace Service B and can be accessed by Service A and Service C so they can determine where to forward messages to at runtime.
The Service Loose Coupling principle can be further applied to ensure that the new Routing service remains decoupled from other services so that it can perform its routing functions independently from service contract invocation.

The Intermediate Routing pattern can be applied together with the Service Agent pattern by removing Service B or Service C from the service composition and replacing it with a service agent capable of intercepting and forwarding the message at runtime based on pre-defined routing logic. The Service Discoverability principle can be further applied to ensure that Service A can be found by any future service consumers.

The Intermediate Routing pattern can be applied together with the Service Agent pattern to establish a service agent capable of intercepting and forwarding the message at runtime based on pre-defined routing logic. The Service Composability principle can be further applied to ensure that all services are designed as effective service composition participants.

QUESTION 18
Refer to Exhibit.

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 and B is minimized? What further step can be taken to avoid consumer-to-implementation coupling with Service Consumer C?

The Service Fagade pattern can be applied to position fagade components between the core service logic and Service Consumers A and B. These fagade components will be designed to regulate the behavior of Service A. The Service Abstraction principle can be applied to hide the implementation details of the core service logic of Service A, thereby shielding this logic from changes to the implementation. The Schema Centralization pattern can be applied to force Service Consumer C to access Service A via one of its existing service contracts.

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 Fagade pattern can be applied to position a fagade 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.

The Service Fagade pattern can be applied to position fagade components between the core service logic and the two service contracts. These fagade components will be designed to regulate the behavior of Service A. The Service Loose Coupling principle can be applied to avoid negative forms of coupling.

The Service Fagade pattern can be applied to position fagade components between the core service logic and the implementation resources (the database and the legacy system). These fagade components will be designed to insulate the core service logic of Service A from the changes in the underlying implementation resources. The Schema Centralization and Endpoint Redirection patterns can also be applied to force Service Consumer C to access Service A via one of its existing service contracts.

QUESTION 19
Refer to Exhibit.

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 that are based on different design standards and technologies than the services In Service Inventory B. As a result, Service A is a SOAP-based Web service and Service B Is a REST service that exchanges JSON-formatted messages. 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.
What steps can be taken to solve these problems?

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.

The Data Format 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 format 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.

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.

The Data Format 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 format to another at runtime. The Asynchronous Queuing pattern can be applied to establish an intermediate queue between Service A and Service B so that when Service A needs to send a message to Service B, the queue will store the message and retransmit it to Service B until it is successfully delivered. The Service Reusability principle can be further applied to Service C together with the Redundant Implementation pattern to help establish a more reusable and scalable service architecture.

QUESTION 20

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 that each provides standardized data access capabilities.
Service A sends its first update request message to Service B (1), which then responds with a message containing either 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 either a success or failure code (4). Finally, Service A sends a request message to Service D (5), which responds with its own message containing either a success or failure code (6).
Services B, C and D are agnostic services that are reused and shared by multiple service consumers. This has caused unacceptable performance degradation for the service consumers of Service A as it is taking too long to complete its overall task. You’ve been asked to enhance the service composition architecture so that Service A provides consistent and predictable runtime performance. You are furthermore notified that a new type of data will be introduced to all three databases. It is important that this data is exchanged in a standardized manner so that the data model used for the data in inter-service messages is the same.
What steps can be taken to fulfill these requirements?

The Compensating Service Transaction pattern can be applied so that exception logic is executed to notify Service A whenever the data access logic executed by Service B, C, or D takes too long. If the execution time exceeds a predefined limit, then the overall service activity is cancelled and a failure code is returned to Service A. The Schema Centralization pattern is applied to ensure that all services involved in the composition use the same schemas to represented the data consistently.

The Composition Autonomy pattern can be applied to establish an isolated environment in which redundant implementations of Services B, C and D are accessed only by Service A. The Canonical Schema pattern can be applied to ensure that the new type of data is represented by the same data model, regardless of which service sends or receives a message containing the data.

The Redundant Implementation pattern is applied to Service A, along with the Service Instance Routing pattern. This allows for multiple instances of Service A to be created across multiple physical implementations, thereby increasing scalability and availability. The Dual Protocols pattern is applied to all services to support proprietary and standardized data models.

The Service Fagade pattern is applied to all services in order to create an intermediary processing layer within each service architecture. The Content Negotiation pattern is applied so that each service fagade component within each service architecture is equipped with the logic required to defer request messages to other service instances when concurrent usage of the service is high, and to further apply the conversation logic necessary to convert proprietary data from a database into the standardized XML schema format.

QUESTION 21
Refer to Exhibit.

Service A is an entity service that provides a Get capability which 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 will occur 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.
The current service composition architecture is using up too many resources due to the repeated invocation of Service A by Service Consumer A and the resulting message exchanges that occur with each invocation.
What steps can be taken to solve this problem?

The Event-Driven Messaging pattern can be applied by establishing a subscriber-publisher relationship between Service A and Service B. This way, every time the data value is updated, an event is triggered and Service B, acting as the publisher, can notify Service A, which acts as the subscriber. The Asynchronous Queuing pattern can be applied between Service A and Service B so that the event notification message sent out by Service B will be received by Service A, even when Service A is unavailable.

The Event-Driven Messaging pattern can be applied by establishing a subscriber-publisher relationship between Service Consumer A and Service A. This way, every time the data value is updated, an event is triggered and Service A, acting as the publisher, can notify Service Consumer A, which acts as the subscriber. The Asynchronous Queuing pattern can be applied between Service Consumer A and Service A so that the event notification message sent out by Service A will be received by Service Consumer A, even when Service Consumer A is unavailable.

The 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.

The Event-Driven Messaging pattern can be applied by establishing a subscriber-publisher relationship between Service Consumer A and a database monitoring agent introduced through the application of the Service Agent pattern. The database monitoring agent monitors updates made by the legacy client to the database. This way, every time the data value is updated, an event is triggered and the database monitoring agent, acting as the publisher, can notify Service Consumer A, which acts as the subscriber.
The Asynchronous Queuing pattern can be applied between Service Consumer A and the database monitoring agent so that the event notification message sent out by the database monitoring agent will be received by Service Consumer A, even when Service Consumer A is unavailable.

QUESTION 22

Service Consumer A sends a message to Service A. There are currently three duplicate implementations of Service A (Implementation 1, Implementation 2 and 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 despite the fact that duplicate implementations of Service A exist, performance is still poor at times. You are also informed that a new service capability will soon need to be added to Service A to introduce functionality that will require access to a shared database being used by many other clients and applications in the IT enterprise. This is expected to add further performance demands on Service A.
How can this service architecture be changed to improve performance in preparation for the addition of the new service capability?

The Standardized Service Contract principle can be applied to ensure that the new service capability extends the existing service contract in a manner that is compliant with current design standards. The Redundant Implementation pattern can be applied to establish separate implementations of Service A that include duplicate databases with copies of the data that Service A requires from the shared database.

The Service Autonomy principle can be applied to further isolate the individual implementations of Service A by separating them onto different physical servers. When the new service capability is added, the Service Data Replication pattern can be applied to give each implementation of Service A its own copy of the data it requires from the shared database.

The Service Loose Coupling principle can be applied together with the Standardized Service Contract principle to ensure that Service Consumer A is not indirectly coupled to the shared database after the new service capability is added to the service contract. The Legacy Wrapper pattern can be applied to establish a new utility service that will provide standardized data access service capabilities for the shared database.

The Service Autonomy principle can be applied to further isolate the individual implementations of Service A by separating them onto different physical servers. When the new service capability is added, the State Repository pattern can be applied to give each implementation of Service A its own copy of the data it requires from the shared database.

QUESTION 23

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 the three services reveals that each contains some agnostic logic that cannot be made available for reuse because it is bundled together with non-agnostic logic.
The assessment also determines that because Service A, 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.
How can the application of the Orchestration pattern improve this architecture?

The application of the Orchestration pattern will result in an environment whereby the Official Endpoint, State Repository, and Service Data Replication patterns are automatically applied, allowing the shared state database to be replicated via official service endpoints for Services A and B so that each task service can have its own dedicated state database.

The application of the Orchestration pattern will result in an environment whereby the non-agnostic logic can be cleanly separated from the agnostic logic that exists in Services A, B, and C, resulting in theneed to design new agnostic services with reuse potential assured through the application of the Service Reusability principle. The State Repository pattern, which is supported by and local to the orchestration environment, provides a central state database that can be shared by Services A and B. The local state database avoids problems with remote communication.

The application of the Orchestration pattern will result in an environment whereby the Compensating Service Transaction is automatically applied, resulting In the opportunity to create sophisticated exception logic that can be used to compensate for the performance problems caused by Services A and B having to remotely access the state database. The API Gateway and Service Broker patterns are also automatically applied, providing common transformation functions in a centralized processing layer to help overcome any disparity in the service contracts that will need to be created for the new agnostic services.

The Orchestration pattern is not applicable to this architecture because it does not support the hosting of the required state repository.

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