org.apache.axis2.clustering.management
Interface NodeManager

All Superinterfaces:

ParameterInclude

All Known Implementing Classes:

DefaultNodeManager

public interface NodeManager
extends ParameterInclude

This interface is responsible for handling configuration management. Configuraion changes include

• Rebooting an entire cluster, in which case, all nodes have to load the new Axis2 configuration in a consistent manner
• Deploying a new service to a cluster or undeploying a service from a cluster
• Changing the policies of a service deployed on the cluster

It is not mandatory to have a NodeManager in a node. In which case the cluster may be used only for High Availability through context replication. However, it is difficult to imagine that a cluster will be deployed in production with only context replication but without cluster configuration management.

The implementation of this interface is set by the ClusterBuilder, by reading the "configurationManager" element in the axis2.xml

e.g.

Method Summary

void	commit() Second phase of the 2-phase commit protocol.
void	exceptionOccurred(Throwable throwable) To notify other nodes that an Exception occurred, during the processing of a NodeManagementCommand
void	prepare() First phase of the 2-phase commit protocol.
void	rollback() Rollback whatever was done
void	sendMessage(NodeManagementCommand command) Execute a NodeManagementCommand
void	setConfigurationContext(ConfigurationContext configurationContext) Set the system's configuration context.

Methods inherited from interface org.apache.axis2.description.ParameterInclude

addParameter, deserializeParameters, getParameter, getParameters, isParameterLocked, removeParameter

Method Detail

prepare

void prepare()
             throws ClusteringFault

First phase of the 2-phase commit protocol. Notifies a node that it needs to prepare to switch to a new configuration.

Throws:

ClusteringFault - If an error occurs while preparing to commit

rollback

void rollback()
              throws ClusteringFault

Rollback whatever was done

Throws:

ClusteringFault - If an error occurs while rolling back a cluster configuration transaction

commit

void commit()
            throws ClusteringFault

Second phase of the 2-phase commit protocol. Notifies a node that it needs to switch to a new configuration.

Throws:

ClusteringFault - If an error occurs while committing a cluster configuration transaction

exceptionOccurred

void exceptionOccurred(Throwable throwable)
                       throws ClusteringFault

To notify other nodes that an Exception occurred, during the processing of a NodeManagementCommand

Parameters:

throwable - The throwable which has to be propogated to other nodes

Throws:

ClusteringFault - If an error occurs while processing the exception message

setConfigurationContext

void setConfigurationContext(ConfigurationContext configurationContext)

Set the system's configuration context. This will be used by the clustering implementations to get information about the Axis2 environment and to correspond with the Axis2 environment

Parameters:

configurationContext - The configuration context

sendMessage

void sendMessage(NodeManagementCommand command)
                 throws ClusteringFault

Execute a NodeManagementCommand

Parameters:

command - The command to be executed

Throws:

ClusteringFault - If an error occurs while sending the message