When there are concurrent requests for a resource, it is necessary to synchronize access.
Therefore:
Implement a scheduler that selects which request will be allowed to execute next.
Scheduling policies may be first-come/first-served, priority-based, or otherwise.
Using the Strategy Pattern, one can customize the behavior of the scheduler for particular configurations or applications.
Consider the Command Pattern for representation of queued requests.
Other Related Patterns: Lock Pattern, Read Write Lock, Mediator Pattern, Interruptible Command, Reactor Pattern
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