Sun GlassFish Enterprise Server 2.1 Developer's Guide

Load-Balanced Message Inflow

You can configure ActivationSpec properties of the jmsra resource adapter in the sun-ejb-jar.xml file for a message-driven bean using activation-config-property elements. Whenever a message-driven bean (EndPointFactory) is deployed, the connector runtime engine finds these properties and configures them accordingly in the resource adapter. See activation-config-property in Sun GlassFish Enterprise Server 2.1 Application Deployment Guide.

The Enterprise Server transparently enables messages to be delivered in random fashion to message-driven beans having same ClientID. The ClientID is required for durable subscribers.

For nondurable subscribers in which the ClientID is not configured, all instances of a specific message-driven bean that subscribe to same topic are considered equal. When a message-driven bean is deployed to multiple instances of the Enterprise Server, only one of the message-driven beans receives the message. If multiple distinct message-driven beans subscribe to same topic, one instance of each message-driven bean receives a copy of the message.

To support multiple consumers using the same queue, set the maxNumActiveConsumers property of the physical destination to a large value. If this property is set, the Sun GlassFish Message Queue software allows multiple message-driven beans to consume messages from same queue. The message is delivered randomly to the message-driven beans. If maxNumActiveConsumers is set to -1, there is no limit to the number of consumers.

To ensure that local delivery is preferred, set addresslist-behavior to priority. This setting specifies that the first broker in the AddressList is selected first. This first broker is the local colocated Message Queue instance. If this broker is unavailable, connection attempts are made to brokers in the order in which they are listed in the AddressList. This setting is the default for Enterprise Server instances that belong to a cluster.

Note –

Some topics in the documentation pertain to features that are available only in domains that are configured to support clusters. Examples of domains that support clusters are domains that are created with the cluster profile or the enterprise profile. For information about profiles, see Usage Profiles in Sun GlassFish Enterprise Server 2.1 Administration Guide.