com.kabira.platform.highavailability

Class NodeNotifier

java.lang.Object

com.kabira.platform.disteng.DENodeNotifier

com.kabira.platform.highavailability.NodeNotifier

@Managed
public abstract class NodeNotifier
extends com.kabira.platform.disteng.DENodeNotifier

The NodeNotifier class. This managed class is extended by applications to get notifications when remote nodes become active or unavailable. Creating an instance of this class enables the active and unavailable callbacks for the local node. These callbacks are called whenever the local node detects that a remote node becomes active or unavailable. Each node which needs notifications must create an instance of this class.

When an instance of this class is created, the active callback is called for each active remote node already discovered by the local node.

The execution order for these callbacks is serialized by the runtime. If a node becomes unavailable while the active callback is executed, the execution of the unavailable callback is deferred until after the active callback finishes execution.

When nodes become active or unavailable, the callback is executed in a system defined transaction. Applications should create and delete instances of this class in a separate transaction that does not make any other calls to methods in the highavailability package. Doing this will reduce the potential for transaction deadlocks when the callbacks are executed.

Constructor Summary

Constructors

Constructor and Description
NodeNotifier()

Method Summary

Modifier and Type	Method and Description
protected abstract void	active(java.lang.String remoteNode) Called when a node becomes active.
protected abstract void	unavailable(java.lang.String remoteNode) Called when a node becomes unavailable.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NodeNotifier

public NodeNotifier()

Method Detail

active

protected abstract void active(java.lang.String remoteNode)

Called when a node becomes active.

Specified by:

active in class com.kabira.platform.disteng.DENodeNotifier

Parameters:

remoteNode - The name of remote node.

This operation is called whenever a remote node becomes active.

Remote work can be executed on the new remote node when this callback is executed.

unavailable

protected abstract void unavailable(java.lang.String remoteNode)

Called when a node becomes unavailable.

Specified by:

unavailable in class com.kabira.platform.disteng.DENodeNotifier

Parameters:

remoteNode - The name of remote node.

This operation is called whenever a remote node becomes unavailable.

Remote work should not be attempted on the unavailable remote node when this callback is executed.