Reactor 1 Intent 2 Also Known As 3 Example

Short Description
The Reactor design pattern handles service requests that are. delivered concurrently to an application by one or more. clients. …

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Content
Reactor
An Object Behavioral Pattern for
Demultiplexing and Dispatching Handles for Synchronous Events
Douglas C. Schmidt
schmidt@cs.wustl.edu
Department of Computer Science
Washington University, St. Louis, MO1
An earlier version of this paper appeared as a chapter in
the book “Pattern Languages of Program Design” ISBN 0-
201-6073-4, edited by Jim Coplien and Douglas C. Schmidt
and published by Addison-Wesley, 1995.
1 Intent
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.
2 Also Known As
Dispatcher, Notifier
3 Example
To illustrate the Reactor pattern, consider the event-driven
server for a distributed logging service shown in Figure 1.
Client applications use the logging service to record information
about their status in a distributed environment. This status
information commonly includes error notifications, debugging
traces, and performance reports. Logging records
are…