12/17/2023 0 Comments Priority queueIt is used to retrieves, but does not remove, the head of this queue, or returns null if this queue is empty. It is used to retrieves, but does not remove, the head of this queue. It is used to retrieves and removes the head of this queue, or returns null if this queue is empty. It is used to retrieves and removes the head of this queue. It is used to insert the specified element into this queue. It is used to insert the specified element into this queue and return true upon success. He provides a third solution that is not discussed here, that involves a different view on responsibilities and deployment using concepts from the 4+1 architectural view model.Public interface Queue extends Collection In a series of blog posts about priority queues, Dennis van der Stelt goes into more details of both the problem and possible solutions and their trade-offs. As mentioned, this introduces tight coupling between sender and receivers.Īnother option could be using publish/subscribe where both the regular- and high priority endpoint both subscribe to a publishing endpoint. Possible solutionsĪ solution is to place the responsibility of deciding which message is a priority message with the sender. As the result would be that if the logic changes to decide if a message has priority, the sender needs to be changed as well. If the Single Responsibility Principle is valued, it is recommended not to introduce more responsibilities into a sender than necessary. This requires a tighter coupling than might be desirable. If an endpoint is required to decide which messages should have a higher priority, it requires knowledge that the receiving endpoint(s) are responsible for. Low couplingĮndpoints should be designed to be autonomous and be able to do their work without having knowledge of how other endpoints work. It should also be possible to scale out differently, compared to the regular business process. Or even decide for a different type of datastore or different hardware. Other decisions could be to use a different datastore, concurrency mode or implement a different caching strategy. The SLA might be breached if the message isn't processed in a specific amount of time, which is far more strict than with regular messages. Different operational considerationsĪnother aspect of priority messages can be a different Service Level Agreement (SLA) than with regular messages. It's likely the design and code should be separated completely from the regular business process. At the very least it's usually more than just the priority of the message. There could be differences in code or even in design. The result is that the design of a component is about more than message priority. Depending on the domain there can be many deviations from the regular business processes. Or a different kind of fee applies or even larger differences in business logic exist than for regular messages. A different type of process could exist for the priority message. Often the need to process messages quicker and have the need for priority messages comes from a business standpoint. This article tries to explain a different type of solution. A special queue next to the regular queue that holds messages that will be processed before messages in the regular queue. This is regularly solved using priority queues. This behavior can potentially awaken the need for those important messages to 'jump the queue' and bypass all those other messages. As queues generally work according to the First In, First Out (FIFO) principle, those important messages have to wait until all messages that arrived earlier, are processed first. Some messages might be considered more important than others. An endpoint is a collection of handlers that process a specific message type.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |