com.sun.sgs.impl.service.nodemap.policy
Class AbstractNodePolicy

java.lang.Object
  com.sun.sgs.impl.service.nodemap.policy.AbstractNodePolicy

All Implemented Interfaces:

NodeAssignPolicy

Direct Known Subclasses:

RoundRobinPolicy

public abstract class AbstractNodePolicy
extends Object
implements NodeAssignPolicy

Abstract node policy class. This class manages the list of nodes that are available for assignment. Subclasses must implement the logic for making the assignments.

See Also:

NodeAssignPolicy.chooseNode(long), NodeAssignPolicy.chooseNode(long, com.sun.sgs.auth.Identity)

Field Summary

protected List<Long>

availableNodes The list of available nodes.

Fields inherited from interface com.sun.sgs.impl.service.nodemap.NodeAssignPolicy

SERVER_NODE

Constructor Summary

protected

AbstractNodePolicy() Creates a new instance of the AbstractNodePolicy.

Method Summary

long	chooseNode(long requestingNode, Identity id) Choose a node to assign an identity to.
void	nodeAvailable(long nodeId) Inform the policy that a node is now available.
void	nodeUnavailable(long nodeId) Inform the policy that a node is no longer available.
void	reset() Reset the policy, informing it that no nodes are available.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.sun.sgs.impl.service.nodemap.NodeAssignPolicy

chooseNode

Field Detail

availableNodes

protected final List<Long> availableNodes

The list of available nodes. Access to this list must be synchronized.

Constructor Detail

AbstractNodePolicy

protected AbstractNodePolicy()

Creates a new instance of the AbstractNodePolicy.

Method Detail

chooseNode

public long chooseNode(long requestingNode,
                       Identity id)
                throws NoNodesAvailableException

Choose a node to assign an identity to. This implementation simply calls NodeAssignPolicy.chooseNode(long), ignoring the id parameter.

Specified by:

chooseNode in interface NodeAssignPolicy

Parameters:

requestingNode - the id of the node making the request, or SERVER_NODE if the system is making the request

id - the identity which needs an assignment.

Returns:

the chosen node's id

Throws:

NoNodesAvailableException - if there are no live nodes to assign to

nodeAvailable

public void nodeAvailable(long nodeId)

Inform the policy that a node is now available.

Specified by:

nodeAvailable in interface NodeAssignPolicy

Parameters:

nodeId - the node ID

nodeUnavailable

public void nodeUnavailable(long nodeId)

Inform the policy that a node is no longer available.

Specified by:

nodeUnavailable in interface NodeAssignPolicy

Parameters:

nodeId - the node ID

reset

public void reset()

Reset the policy, informing it that no nodes are available.

Specified by:

reset in interface NodeAssignPolicy