Fiorano Queues should be configured with the parameter, MessageGroupingEnabled to denote that the messages that arrive onto this destination should be grouped and sent to the consuming applications. And from the client application point of view, JMS producers should be changed to fill in the JMSXGroupID message header with some String value of any choice and a message sequence property JMSXGroupSeq with positive integer values.
In order to close a message group, you can add a negative sequence number in the JMS producer. A sequence close signal should be on the LAST message of a group and the message is sent to the original owner.
This will close the message group so if another message is sent in the future with the same message group ID it will automatically be re-assigned to a new consumer.
Preferred Groups
In addition to the above-mentioned Message grouping, the consuming applications can optionally indicate the list of message groups it might be interested in so that the server will assign those groups to it, if they weren't assigned already to any other consumer. This should be included in String format while creating a message consumer (in place of MessageSelector expression) and understandable by the FioranoMQ Server such that it can parse the expression and note the MessageGroups that the MessageConsumer is interested in. The preferred groups should be mentioned in the following way:
As mentioned above, each "Preferred Group" is separated by the semi-colon ; character.
This mechanism is particularly helpful when working with High Availability when the Consuming applications fail-over to the Backup HA Server. In the event of Primary Server failure, the Backup server takes over and triggers the consuming applications to failover their corresponding JMS Connections to the Backup server. In case Preferred Groups are set for a QueueReceiver, the MessageGroups which were handled by a consumer before the PRIMARY SERVER FAILURE event were re-assigned to the same consumer even after the Backup Server takes over.