4.1.2 Monitoring Legacy Connectors Using the Heartbeat Mechanism

All connectors provided in the Java DMK implement a heartbeat mechanism. This is true for both standard connectors and legacy connectors. This section describes the heartbeat mechanism used for legacy RMI, HTTP, and HTTPS connections. For information on the heartbeat mechanism used for standard connectors, see 2.3.1.3 Monitoring Standard Connectors Using the Heartbeat Mechanism.

The heartbeat enables both the agent and manager applications to detect when a connection is lost, either because the communication channel is interrupted or because one of the applications has been stopped.

The connector client and connector server components exchange heartbeat messages periodically. When a heartbeat is not returned or an expected heartbeat is not received, both components begin a retry and timeout period. If the connection is not reestablished, both the connector client and the connector server free the resources allocated for that connection.

The heartbeat mechanism is only configurable on the manager side, the connector server simply replies to heartbeats. The manager application can set the retry policy as determined by the heartbeat period and the number of retries. The manager application can also register for heartbeat notifications that are sent whenever a connection is established, retried, reestablished, lost, or terminated.