The delivery modes supported by the JMS API are PERSISTENT and
NON_PERSISTENT.
A client marks a message as persistent if it feels that the application will
have problems if the message is lost in transit. A client marks a message as
non-persistent if an occasional lost message is tolerable. Clients use
delivery mode to tell a JMS provider how to balance message transport
reliability with throughput.
Delivery mode covers only the transport of the message to its destination.
Retention of a message at the destination until its receipt is acknowledged
is not guaranteed by a PERSISTENT delivery mode. Clients
should assume that message retention policies are set administratively.
Message retention policy governs the reliability of message delivery from
destination to message consumer. For example, if a client's message storage
space is exhausted, some messages may be dropped in accordance with a
site-specific message retention policy.
A message is guaranteed to be delivered once and only once by a JMS provider
if the delivery mode of the message is PERSISTENT and if the
destination has a sufficient message retention policy.
version:
1.0 - 7 August 1998
author:
Mark Hapner
author:
Rich Burridge |