org.apache.axis2.clustering
Interface ClusteringAgent

All Superinterfaces:

ParameterInclude

All Known Implementing Classes:

TribesClusteringAgent

public interface ClusteringAgent
extends ParameterInclude

This is the main interface in the Axis2 clustering implementation. In order to plug-in a new clustering implementation, this interface has to be implemented.

The initilization of a node in the cluster is handled here. It is also responsible for getting this node to join the cluster. This node should not process any Web services requests until it successfully joins the cluster. Generally, this node will also need to obtain the state information and/or configuration information from a neighboring node. This interface is also responsible for properly instantiating a StateManager & NodeManager. In the case of a static membership scheme, this members are read from the axis2.xml file and added to the ClusteringAgent.

In the axis2.xml, the instance of this interface is specified using the "clustering" class attribute. e.g. <clustering class="org.apache.axis2.clustering.tribes.TribesClusterAgent"> specifies that the TribesClusterAgent class is the instance of this interface that needs to be used.

There can also be several "parameter" elements, which are children of the "clustering" element in the axis2.xml file. Generally, these parameters will be specific to the ClusteringAgent implementation.

Method Summary

void	addGroupManagementAgent(GroupManagementAgent agent, String applicationDomain) Set the load balance event handler which will be notified when load balance events occur.
void	finalize() Do cleanup & leave the cluster
Set<String>	getDomains() Get all the domains that this ClusteringAgent belongs to
GroupManagementAgent	getGroupManagementAgent(String applicationDomain) Get the LoadBalanceEventHandler which corresponds to the applicationDomain This will be valid only when this node is running in loadBalance mode
List<Member>	getMembers() Get the list of members in a static group
NodeManager	getNodeManager()
StateManager	getStateManager()
void	init() Initialize this node, and join the cluster
List<ClusteringCommand>	sendMessage(ClusteringMessage msg, boolean isRpcMessage) Send a message to all members in this member's primary cluster
void	setConfigurationContext(ConfigurationContext configurationContext) Set the system's configuration context.
void	setMembers(List<Member> members) Set the static members of the cluster.
void	setNodeManager(NodeManager nodeManager) Set the NodeManager corresponding to this ClusteringAgent.
void	setStateManager(StateManager stateManager) Set the StateManager corresponding to this ClusteringAgent.
void	shutdown() Disconnect this node from the cluster.

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

addParameter, deserializeParameters, getParameter, getParameters, isParameterLocked, removeParameter

Method Detail

init

void init()
          throws ClusteringFault

Initialize this node, and join the cluster

Throws:

ClusteringFault - If an error occurs while initializing this node or joining the cluster

finalize

void finalize()

Do cleanup & leave the cluster

getStateManager

StateManager getStateManager()

Returns:

The StateManager

getNodeManager

NodeManager getNodeManager()

Returns:

The NodeManager

setStateManager

void setStateManager(StateManager stateManager)

Set the StateManager corresponding to this ClusteringAgent. This is an optional attribute. We can have a cluster with no context replication, in which case the contextManager will be null. This value is set by the ClusterBuilder, by reading the "contextManager" element in the axis2.xml

e.g.

Parameters:

stateManager - The StateManager instance

setNodeManager

void setNodeManager(NodeManager nodeManager)

Set the NodeManager corresponding to this ClusteringAgent. This is an optional attribute. We can have a cluster with no configuration management, in which case the configurationManager will be null. This value is set by the ClusterBuilder, by reading the "configurationManager" element in the axis2.xml

e.g.

Parameters:

nodeManager - The NodeManager instance

shutdown

void shutdown()
              throws ClusteringFault

Disconnect this node from the cluster. This node will no longer receive membership change notifications, state change messages or configuration change messages. The node will be " "standing alone" once it is shutdown. However, it has to continue to process Web service requests.

Throws:

ClusteringFault - If an error occurs while leaving the cluster

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

setMembers

void setMembers(List<Member> members)

Set the static members of the cluster. This is used only with static group membership

Parameters:

members - Members to be added

getMembers

List<Member> getMembers()

Get the list of members in a static group

Returns:

The members if static group membership is used. If any other membership scheme is used, the values returned may not be valid

addGroupManagementAgent

void addGroupManagementAgent(GroupManagementAgent agent,
                             String applicationDomain)

Set the load balance event handler which will be notified when load balance events occur. This will be valid only when this node is running in loadBalance mode

Parameters:

agent - The load balance event handler

applicationDomain - The application domain which is handled by the eventHandler

getGroupManagementAgent

GroupManagementAgent getGroupManagementAgent(String applicationDomain)

Get the LoadBalanceEventHandler which corresponds to the applicationDomain This will be valid only when this node is running in loadBalance mode

Parameters:

applicationDomain - The application domain to which the application nodes being load balanced belong to

Returns:

LoadBalanceEventHandler which corresponds to the applicationDomain

getDomains

Set<String> getDomains()

Get all the domains that this ClusteringAgent belongs to

Returns:

the domains of this ClusteringAgent

sendMessage

List<ClusteringCommand> sendMessage(ClusteringMessage msg,
                                    boolean isRpcMessage)
                                    throws ClusteringFault

Send a message to all members in this member's primary cluster

Parameters:

msg - The message to be sent

isRpcMessage - Indicates whether the message has to be sent in RPC mode

Returns:

A list of responses if the message is sent in RPC mode

Throws:

ClusteringFault - If an error occurs while sending the message