tapahtumakäsittelijä

Tapahtumakäsittelijä is a Finnish term that translates to "event handler" in English. In software development and computer science, an event handler is a specific function or routine that is executed in response to a particular event. Events can be triggered by various sources, such as user interactions (like clicking a button or pressing a key), system occurrences (like a file being accessed or an error happening), or messages from other parts of the system.

When an event occurs, the program's event loop or a similar mechanism detects it and identifies the appropriate event handler associated with that event. The event handler then performs a predefined set of actions. This mechanism allows programs to be responsive to external stimuli and internal changes. For example, in a graphical user interface, clicking a "save" button triggers an event, and the associated event handler would execute the code responsible for saving the current data.

Event handlers are a fundamental concept in building interactive and dynamic applications. They enable systems to react appropriately to user input and system states, making software functional and user-friendly. The design of event handlers often involves associating specific functions with specific event types, ensuring that the correct logic is executed when an event takes place. This decoupled approach allows for modularity and easier management of complex program behaviors.