Appian processes can send messages to various destinations using JMS.

The Appian events framework uses the point to point (p2p) Queue model of the Java Messaging Service (JMS). When sending messages, one point is Appian; the other point can be any destination, either Topic (publish/subscribe) or Queue (p2p).

Appian ships with a special Queue destination named Process. Messages sent to Process bypass JMS and are sent directly to the Process Design and Execution Engines in Appian. However, while messages sent to Process are not sent externally, Appian receives messages sent to the JMS Process queue.

Additional JMS destinations can be added in a custom XML file. Although labeled as topics for backward compatibility, they can be any destination, either Topic or Queue (so long as the application server’s JMS feature supports both topics and queues from one connection factory — otherwise, only the configured connection factory’s destinations are available). The JNDI name of a topic or a queue is listed in the <topic name="name"> tag. The displayName tag indicates the name displayed in the user interface for the destination. The messageType tags (children of messageTypes) indicate the types of messages that can be sent. The messageType values are as listed in <APPIAN_HOME>/deployment/web.war/WEB-INF/conf/process/message-types.xml.

By default, the messageType values are:

0	=	Process to Process
1	=	External to Process
2	=	Email

A custom XML file must be used to add a messageType, such as the following example.

jms-topics-custom.xml Example

 <?xml version="1.0" encoding="ISO-8859-1" ?>
 
 <topics>
   <topic name="Sample1">
     <displayName>Sample1</displayName>
     <messageTypes>
       <messageType id="0" />
       <messageType id="1" />
     </messageTypes>
   </topic>
 </topics>