What are resource adaptors and resource adaptor entities?
Resource adaptors (RAs) are SLEE components which let particular network protocols or APIs be used in the SLEE. They typically include a set of configurable properties (such as address information of network endpoints, URLs to external systems, or internal timer-timeout values). These properties may include default values. A resource adaptor entity is a particular configured instance of a resource adaptor, with defined values for all of that RA's configuration properties.
See the following topics in this section for an explanation of each of the commands in the illustration.
Resource adaptor entity lifecycle states
The SLEE lifecycle states are:
The resource adaptor entity has been configured and initialised. It is ready to be activated, but may not yet create activities or fire events to the SLEE. Typically, it is not connected to network resources.
The resource adaptor entity is connected to the resources it needs to function (assuming they are available), and may create activities and fire events to the SLEE.
The resource adaptor entity may not create new activities in the SLEE, but may fire events to the SLEE on already existing activities. A resource adaptor entity transitions out of the STOPPING state, returning to the INACTIVE state, when all activities it owns have either ended or been assigned to another node for continued processing.
As explained in 1 About SLEE Operational States, each event-router node in a Rhino cluster maintains its own lifecycle state machine, independent of other nodes in the cluster. This is also true for each resource adaptor entity: one resource adaptor entity might be INACTIVE on one node in a cluster, ACTIVE on another, and STOPPING on a third. The operational state of a resource adaptor entity on each cluster node also persists to the disk-based database.
A resource adaptor entity will enter the INACTIVE state, after node bootup and initialisation completes, if the database's persistent operational state information for that resource adaptor entity is missing, or is set to INACTIVE or STOPPING.
And, like node operational states, you can change the operational state of a resource adaptor entity at any time, as long as least one node in the cluster is available to perform the management operation (regardless of whether or not the node whose operational state being changed is a current cluster member). For example, you might activate a resource adaptor entity on node 103 before node 103 is booted — then, when node 103 boots, and after it completes initialisation, that resource adaptor entity will transition to the ACTIVE state.