||This article needs additional citations for verification.
(March 2010)| In software architecture, publish–subscribe is a
messaging pattern where senders of messages, called publishers,
do not program the messages to be sent directly to specific
receivers, called subscribers. Instead, published messages are
characterized into classes, without knowledge of what, if any,
subscribers there may be. Similarly, subscribers express
interest in one or more classes, and only receive messages that
are of interest, without knowledge of what, if any, publishers
there are. Pub/sub is a sibling of the message queue paradigm,
and is typically one part of a larger message-oriented
middleware system. Most messaging systems support both the
pub/sub and message queue models in their API, e.g. Java Message
Service (JMS). Message filtering  In the pub/sub model,
subscribers typically receive only a subset of the total
messages published. The process of selecting messages for
reception and processing is called filtering. There ar