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Priority Queue Pattern

Decoupling Behavioral


Prioritize requests sent to services so that requests with a higher priority are received and processed more quickly than those of a lower priority. This pattern is useful in applications that offer different service level guarantees to individual clients.


Applications may delegate specific tasks to other services; for example, to perform background processing or to integrate with other applications or services. In the cloud, a message queue is typically used to delegate tasks to background processing. In many cases the order in which requests are received by a service is not important. However, in some cases it may be necessary to prioritize specific requests. These requests should be processed earlier than others of a lower priority that may have been sent previously by the application.

Class diagram

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Use the Property pattern when

  • The system must handle multiple tasks that might have different priorities.
  • Different users or tenants should be served with different priority..

Real world examples

  • Priority Queue Pattern Microsoft Azure does not provide a queuing mechanism that natively support automatic prioritization of messages through sorting. However, it does provide Azure Service Bus topics and subscriptions, which support a queuing mechanism that provides message filtering, together with a wide range of flexible capabilities that make it ideal for use in almost all priority queue implementations.