If a Service Consumer Program Needs to Get Data from a Service

question 54

Multiple Choice

If a service consumer program needs to get data from a service that is not available, it can poll the service by periodically issuing a request message. This type of interaction can be inefficient because it can lead to unnecessary message transmissions. Which of the following statements describes a solution to this problem?

• A) By applying the Messaging Metadata pattern, the service consumer can write a request identifier in the message header. Service agents then intercept the request messages and do not forward those that contain a previously detected identifier. This practice eliminates the delivery of the duplicate messages to the service.
• B) The Event-Driven Messaging pattern can be applied to establish a messaging framework in which service consumers are automatically notified of relevant runtime service events.
• C) By applying the Atomic Service Transaction pattern, a service can be designed to invoke an alternative exception handling process when it is unavailable to receive a given message.
• D) None of these statements describe solutions that directly solve this problem.

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Definitions:

Post-traumatic Stress Disorder

A psychiatric disorder that may occur in people who have experienced or witnessed a traumatic event, characterized by flashbacks, nightmares, and severe anxiety.

Nightmares

Disturbing dreams that cause fear or anxiety, often awakening the sleeper.

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A facility in which individuals are forcibly confined and denied a variety of freedoms under the authority of the state as a form of punishment.

Specific Phobic Disorder

A type of anxiety disorder characterized by a strong, irrational fear of and desire to avoid specific objects, activities, or situations that pose little or no actual danger.