Question

Reactor pattern is explained in wikipedia, and it’s a bit too abstract. Can you describe this pattern in a more concrete way? Ideally with code snippets or high-level class diagrams describing some applications of reactor pattern.

Answer 1

You might want to check the original paper describing it http://www.dre.vanderbilt.edu/~schmidt/PDF/reactor-siemens.pdf

The Reactor design pattern handles service requests that are
delivered concurrently to an application by one or more
clients. Each service in an application may consist of
serveral methods and is represented by a separate event handler
that is responsible for dispatching service-specific requests.
Dispatching of event handlers is performed by an initiation
dispatcher, which manages the registered event handlers.
Demultiplexing of service requests is performed by a
synchronous event demultiplexer.