Overview of correlator-integrated messaging for JMS
Note: Correlator-integrated JMS is deprecated and will be removed in a future release.
The Java Message Service (JMS) provides a common programming model for asynchronously sending events and data across enterprise messaging systems. JMS supports two models, “publish-and-subscribe” for one-to-many message delivery and “point-to-point” for one-to-one message delivery. Apama’s correlator-integrated messaging for JMS supports both these models.
When configured to use correlator-integrated messaging for JMS, Apama applications map incoming JMS messages to Apama events and map outgoing Apama events to JMS messages.
Apama’s correlator-integrated messaging for JMS supports the following levels of reliability, built upon the reliability mechanisms provided by JMS:
BEST_EFFORT
AT_LEAST_ONCE
EXACTLY_ONCE
APP_CONTROLLED
(can be set for only receivers, not for senders)
When the reliability level is set to EXACTLY_ONCE
or AT_LEAST_ONCE
or APP_CONTROLLED
then delivery is guaranteed because messages are robustly retained by the broker until they are received and acknowledged by the Apama client. The APP_CONTROLLED
reliability mode lets the application control when messages are acknowledged to the broker.
When the reliability level is set to BEST_EFFORT
, message delivery is not guaranteed. For applications that do not require guaranteed message delivery, the BEST_EFFORT
mode provides greater performance.
Note: If a license file cannot be found, the correlator is limited to BEST_EFFORT
only messaging. See Running Apama without a license file.
In Apama Plugin for Eclipse, you can specify configuration for JMS, either in the correlator-integrated adapter for JMS editor or by editing sections of the XML and .properties
configuration files directly. Note, however that the mapping configuration should always be edited by using Apama’s adapter editor.