Overview of using Universal Messaging in Apama applications

Comparison of Apama channels and Universal Messaging channels

Choosing when to use Universal Messaging channels and when to use Apama channels

General steps for using Universal Messaging in Apama applications

Using Universal Messaging channels instead of engine_connect

Using Universal Messaging channels instead of configuring IAF adapter connections

Considerations for using Universal Messaging channels

In an Apama application, correlators and IAF adapters can connect to Universal Messaging realms or clusters. A correlator or IAF adapter connected to a Universal Messaging realm or cluster uses Universal Messaging as a message bus for sending Apama events between Apama components. Connecting a correlator or IAF adapter to Universal Messaging is an alternative to

Specifying a connection between two correlators by executing the engine_connect correlator tool. This is the main reason to use Universal Messaging.

Defining connections between an IAF adapter and particular correlators in the <apama> element of an IAF configuration file. This is a secondary reason to use Universal Messaging. You might find that having some IAF adapters connected to Universal Messaging is a good fit for your application.

Using Universal Messaging can simplify an Apama application configuration. Instead of specifying many point-to-point connections, you specify only the address (or addresses) of the Universal Messaging realm or cluster. Apama components connected to the same Universal Messaging realm can use Universal Messaging channels to send and receive events. (Universal Messaging channels are equivalent to JMS topics.) Connections to Universal Messaging are automatically made as needed, giving extra flexibility in how the application is designed.

When an Apama application uses Universal Messaging, a correlator automatically connects to the required Universal Messaging channels. There is no need to explicitly connect Universal Messaging channels to individual correlators. A correlator automatically receives events on Universal Messaging channels that monitors subscribe to and automatically sends events to Universal Messaging channels.

When using the connectivity plug-in for Universal Messaging, you can also talk to non-Apama applications which are connected to Universal Messaging and configure a chain definition to translate those message payloads into ones suitable for Apama.