Editing Event-driven programming (section)

{{short description|Computer programming paradigm}}

In [[computer programming]], '''event-driven programming''' is a [[programming paradigm]] in which the [[Control flow|flow of the program]] is determined by external [[Event (computing)|events]]. [[User interface|UI]] events from [[computer mouse|mice]], [[computer keyboard|keyboards]], [[touchpads]] and [[touchscreens]], and external [[sensor]] inputs are common cases. Events may also be programmatically generated, such as from [[message passing|messages from other programs]], notifications from other [[thread (computer science)|threads]], or other [[Computer network|network]] events.

Event-driven programming is the dominant paradigm used in [[graphical user interface]]s applications and network servers.

In an event-driven application, there is generally an [[event loop]] that listens for events and then triggers a [[callback (computer programming)|callback function]] when one of those events is detected.

Event-driven programs can be written in any [[programming language]], although the task is easier in languages that provide [[abstraction (computer science)|high-level abstractions]].

Although they do not exactly fit the event-driven model, [[Interrupt handler|interrupt handling]] and [[exception handling]] have many similarities.

It is important to differentiate between [[Event-driven messaging|event-driven]] and [[Message queue|message-driven (aka queue driven)]] paradigms: Event-driven services (e.g. [[Amazon Simple Notification Service|AWS SNS]]) are decoupled from their consumers. Whereas queue / message driven services (e.g. [[Amazon Simple Queue Service|AWS SQS]]) are coupled with their consumers.<ref>{{Cite book |title=Domain-Driven Design with Java - A Practitioner's Guide |year=2022 |isbn=9781800564763 |last1=Chandrasekaran |first1=Premanand |last2=Krishnan |first2=Karthik |last3=Ford |first3=Neal |last4=Byars |first4=Brandon |last5=Buijze |first5=Allard |publisher=Packt Publishing }}</ref>