co.paralleluniverse.galaxy

Interface Cluster

public interface Cluster

The cluster management service. Provides information and events on the nodes comprising the grid's cluster. The cluster manages most of the information via a DistributedTree that's implemented either on top of JGroups or Apache ZooKeeper.

Method Summary

Methods

Modifier and Type	Method and Description
void	addLifecycleListener(LifecycleListener listener) Adds a listener for lifecycle events.
void	addMasterNodePropertyListener(String property, NodePropertyListener listener) Adds a listener that will be notified when a node property has changed on one of the master nodes.
void	addNodeChangeListener(NodeChangeListener listener) Adds a listener for events relating nodes joining and leaving the cluster.
void	addNodeProperty(String property, boolean requiredForPeer, boolean requiredForServer, ReaderWriter<?> readerWriter) Adds a new node property that will be visible on the cluster.
void	addSlaveConfigurationListener(SlaveConfigurationListener listener) Adds a listener for events relating to this master-slaves node group configuration.
void	addSlaveNodePropertyListener(String property, NodePropertyListener listener) Adds a listener that will be notified when a node property has changed on one of this node's slaves.
DistributedTree	getDistributedTree() Returns the DistributedTree used by the cluster.
NodeInfo	getMaster(short node) Returns a given node-group master if this node is a slave.
Collection<NodeInfo>	getMasters() Returns all the current, online master nodes.
NodeInfo	getMyMaster() Returns this node's master node if this is a slave.
short	getMyNodeId() Returns this cluster node's ID.
NodeInfo	getMyNodeInfo() Returns this cluster node's info.
List<NodeInfo>	getMySlaves() Returns this node's master node if this is a slave.
NodeInfo	getNodeInfoByName(String nodeName) Returns a NodeInfo for any cluster node, identified by its (unique) name.
Set<Short>	getNodes() Returns the IDs of all online nodes (each master and slaves group of nodes is listed once - remember: masters and slaves share the same ID).
Set<NodeInfo>	getNodesByProperty(String propertyName, Object value) Returns a set of NodeInfo for any cluster node, with a property equal to the given value.
Object	getUnderlyingResource() Returns the main resource used by the cluster for coordination, namely a org.jgroups.JChannel for a JGroups-based cluster or a com.netflix.curator.framework.CuratorFramework for a ZooKeeper-based cluster.
void	goOffline() Leave the cluster and shutdown the JVM.
boolean	hasServer() Returns true if the grid is configured to use a server.
boolean	isMaster() Returns true if this node is a master; false if it's a slave.
boolean	isMaster(NodeInfo node) Returns true if the given node is a master; false if it's a slave.
boolean	isOnline() Returns true if this node is online (operational and visible to other nodes).
void	removeLifecycleListener(LifecycleListener listener) Removes a LifecycleListener.
void	removeMasterNodePropertyListener(String property, NodePropertyListener listener) Removes a NodePropertyListener listening on master nodes.
void	removeNodeChangeListener(NodeChangeListener listener) Removes a NodeChangeListener.
void	removeSlaveConfigurationListener(SlaveConfigurationListener listener) Removes a SlaveConfigurationListener.
void	removeSlaveNodePropertyListener(String property, NodePropertyListener listener) Removes a NodePropertyListener listening on this node's slaves.
void	setNodeProperty(String property, Object value) Sets a property for this node.

Method Detail

getMyNodeId

short getMyNodeId()

Returns this cluster node's ID. The ID is not unique in the cluster - a master and its slaves all share the same ID.

Returns:

This cluster node's ID.

getMyNodeInfo

NodeInfo getMyNodeInfo()

Returns this cluster node's info. This node's name (accessed through NodeInfo.getName()) is unique in the cluster.

Returns:

This cluster node's info.

getNodeInfoByName

NodeInfo getNodeInfoByName(String nodeName)

Returns a NodeInfo for any cluster node, identified by its (unique) name.

Parameters:

nodeName - The node's (unique) name.

Returns:

The node's information.

getNodesByProperty

Set<NodeInfo> getNodesByProperty(String propertyName,
                               Object value)

Returns a set of NodeInfo for any cluster node, with a property equal to the given value.

Parameters:

propertyName - The property we want to compare to the given value.

value - The requested value of the property.

Returns:

The nodes having the requested property value.

hasServer

boolean hasServer()

Returns true if the grid is configured to use a server.

Returns:

true if the grid is configured to use a server; false otherwise.

isOnline

boolean isOnline()

Returns true if this node is online (operational and visible to other nodes).

Returns:

true if this node is online and false otherwise.

isMaster

boolean isMaster()

Returns true if this node is a master; false if it's a slave.

Returns:

true if this node is a master; false if it's a slave.

getNodes

Set<Short> getNodes()

Returns the IDs of all online nodes (each master and slaves group of nodes is listed once - remember: masters and slaves share the same ID).

Returns:

A set containing the IDs of all online nodes.

getMasters

Collection<NodeInfo> getMasters()

Returns all the current, online master nodes.

Returns:

A collection containing all the current, online master nodes.

getMyMaster

NodeInfo getMyMaster()

Returns this node's master node if this is a slave.

Returns:

This node's master node if this is a slave and null otherwise.

getMySlaves

List<NodeInfo> getMySlaves()

Returns this node's master node if this is a slave.

Returns:

This node's master node if this is a slave. null otherwise.

getMaster

NodeInfo getMaster(short node)

Returns a given node-group master if this node is a slave.

Parameters:

node - The node ID of the mater-slaves group (remember: masters and slaves share the same ID) the master of which we want.

Returns:

The master of the given node-group.

isMaster

boolean isMaster(NodeInfo node)

Returns true if the given node is a master; false if it's a slave.

Parameters:

node -

Returns:

true if the given node is a master; false if it's a slave.

getDistributedTree

DistributedTree getDistributedTree()

Returns the DistributedTree used by the cluster. You may use the tree for your own purposes. The cluster protects any internal Galaxy data in the tree from accidental deletion or modification.

Returns:

The DistributedTree used by the cluster.

addLifecycleListener

void addLifecycleListener(LifecycleListener listener)

Adds a listener for lifecycle events.

Parameters:

listener - The listener

removeLifecycleListener

void removeLifecycleListener(LifecycleListener listener)

Removes a LifecycleListener.

Parameters:

listener - The listener.

addSlaveConfigurationListener

void addSlaveConfigurationListener(SlaveConfigurationListener listener)

Adds a listener for events relating to this master-slaves node group configuration.

Parameters:

listener - The listener.

removeSlaveConfigurationListener

void removeSlaveConfigurationListener(SlaveConfigurationListener listener)

Removes a SlaveConfigurationListener.

Parameters:

listener - The listener.

addNodeChangeListener

void addNodeChangeListener(NodeChangeListener listener)

Adds a listener for events relating nodes joining and leaving the cluster.

Parameters:

listener - The listener.

removeNodeChangeListener

void removeNodeChangeListener(NodeChangeListener listener)

Removes a NodeChangeListener.

Parameters:

listener - The listener.

addMasterNodePropertyListener

void addMasterNodePropertyListener(String property,
                                 NodePropertyListener listener)

Adds a listener that will be notified when a node property has changed on one of the master nodes.

Parameters:

property - The property on whose changes we want to listen.

listener - The listener.

removeMasterNodePropertyListener

void removeMasterNodePropertyListener(String property,
                                    NodePropertyListener listener)

Removes a NodePropertyListener listening on master nodes.

Parameters:

property - The property on the listener is listening on.

listener -

addSlaveNodePropertyListener

void addSlaveNodePropertyListener(String property,
                                NodePropertyListener listener)

Adds a listener that will be notified when a node property has changed on one of this node's slaves.

Parameters:

property - The property on whose changes we want to listen.

listener - The listener.

removeSlaveNodePropertyListener

void removeSlaveNodePropertyListener(String property,
                                   NodePropertyListener listener)

Removes a NodePropertyListener listening on this node's slaves.

Parameters:

property - The property on the listener is listening on.

listener -

addNodeProperty

void addNodeProperty(String property,
                   boolean requiredForPeer,
                   boolean requiredForServer,
                   ReaderWriter<?> readerWriter)

Adds a new node property that will be visible on the cluster.

If required is true, tells the cluster that each node must have the given property set to a non-null value in order to be online. This would not normally be done by a user process, as it would require that his method be called during the Spring container initialization, i.e. in a Component's init() or postInit().

Parameters:

property - The property's name.

requiredForPeer - Whether a non-null value for this property is required for the a peer to be online. For properties added by user processes, this should be false.

requiredForServer - Whether a non-null value for this property is required for a server node to be online. For properties added by user processes, this should be false.

readerWriter - A ReaderWriter instance to read and write this property to and from the distributed tree.

setNodeProperty

void setNodeProperty(String property,
                   Object value)

Sets a property for this node.

Parameters:

property - The property name being set.

value - The new property value.

getUnderlyingResource

Object getUnderlyingResource()

Returns the main resource used by the cluster for coordination, namely a org.jgroups.JChannel for a JGroups-based cluster or a com.netflix.curator.framework.CuratorFramework for a ZooKeeper-based cluster.

Returns:

The main resource used by the cluster for coordination, currently of type org.jgroups.JChannel or org.apache.zookeeper.ZooKeeper.

goOffline

void goOffline()

Leave the cluster and shutdown the JVM. This would take the node offline and result in a call to LifecycleListener.offline(). This action cannot be reversed - the JVM must be restarted for the node to come back online.