org.modeshape.jcr.clustering

Class ClusteringService

java.lang.Object

org.modeshape.jcr.clustering.ClusteringService

@ThreadSafe
public final class ClusteringService
extends Object

ModeShape service which handles sending/receiving messages in a cluster via JGroups

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	ClusteringService.Listener
protected class	ClusteringService.Receiver

Field Summary

Fields

Modifier and Type	Field and Description
protected Set<MessageConsumer<Serializable>>	consumers A list of message consumers which register themselves with this service.
protected AtomicBoolean	isOpen Flag that dictates whether this service has connected to the cluster.
protected org.jgroups.blocks.locking.LockService	lockService The service used for cluster-wide locking
protected static Logger	LOGGER
protected AtomicInteger	membersInCluster The numbers of members in the cluster

Constructor Summary

Constructors

Constructor and Description
ClusteringService() Creates an empty, not started clustering service.

Method Summary

Methods

Modifier and Type	Method and Description
void	addConsumer(MessageConsumer<? extends Serializable> consumer) Adds a new message consumer to this service.
String	clusterName() Returns the name of the cluster which has been configured for this service.
protected Serializable	fromByteArray(byte[] data, ClassLoader classLoader)
long	getMaxAllowedClockDelayMillis() Returns the maximum accepted delay in clock time between cluster members.
boolean	isOpen() Checks if this instance is open or not (open means the JGroups channel has been connected).
int	membersInCluster() Returns the number of members in the cluster.
boolean	multipleMembersInCluster() Checks if the cluster has multiple members.
boolean	sendMessage(Serializable payload) Sends a message of a given type across a cluster.
void	shutdown() Shuts down and clears resources held by this service.
ClusteringService	startForked(org.jgroups.Channel mainChannel) Starts a new clustering service by forking a channel of an existing JGroups channel.
ClusteringService	startStandalone(String clusterName, String jgroupsConfig) Starts a standalone clustering service which in turn will start & connect its own JGroup channel.
boolean	tryLock(long time, TimeUnit unit) Acquires a cluster-wide lock, waiting a maximum amount of time for it.
void	unlock() Unlocks a previously acquired cluster-wide lock.

Methods inherited from class java.lang.Object

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

Field Detail

LOGGER

protected static final Logger LOGGER

isOpen

protected final AtomicBoolean isOpen

Flag that dictates whether this service has connected to the cluster.

membersInCluster

protected final AtomicInteger membersInCluster

The numbers of members in the cluster

lockService

protected org.jgroups.blocks.locking.LockService lockService

The service used for cluster-wide locking

consumers

protected final Set<MessageConsumer<Serializable>> consumers

A list of message consumers which register themselves with this service.

Constructor Detail

ClusteringService

public ClusteringService()

Creates an empty, not started clustering service.

Method Detail

startStandalone

public ClusteringService startStandalone(String clusterName,
                                String jgroupsConfig)

Starts a standalone clustering service which in turn will start & connect its own JGroup channel.

Parameters:

clusterName - the name of the cluster to which the JGroups channel should connect.

jgroupsConfig - either the path or the XML content of a JGroups configuration file; may be null

Returns:

this instance

startForked

public ClusteringService startForked(org.jgroups.Channel mainChannel)

Starts a new clustering service by forking a channel of an existing JGroups channel.

Parameters:

mainChannel - a Channel instance; may not be null.

Returns:

this instance

addConsumer

public void addConsumer(MessageConsumer<? extends Serializable> consumer)

Adds a new message consumer to this service.

Parameters:

consumer - a MessageConsumer instance.

shutdown

public void shutdown()

Shuts down and clears resources held by this service.

tryLock

public boolean tryLock(long time,
              TimeUnit unit)

Acquires a cluster-wide lock, waiting a maximum amount of time for it.

Parameters:

time - an amount of time

unit - a TimeUnit; may not be null

Returns:

true if the lock was successfully acquired, false otherwise

See Also:

Lock.tryLock(long, java.util.concurrent.TimeUnit)

unlock

public void unlock()

Unlocks a previously acquired cluster-wide lock.

See Also:

Lock.unlock()

isOpen

public boolean isOpen()

Checks if this instance is open or not (open means the JGroups channel has been connected).

Returns:

true if the service is open, false otherwise.

multipleMembersInCluster

public boolean multipleMembersInCluster()

Checks if the cluster has multiple members.

Returns:

true if the cluster has multiple members, false otherwise.

membersInCluster

public int membersInCluster()

Returns the number of members in the cluster.

Returns:

the number of active members

clusterName

public String clusterName()

Returns the name of the cluster which has been configured for this service.

Returns:

a String the name of the cluster; never null

getMaxAllowedClockDelayMillis

public long getMaxAllowedClockDelayMillis()

Returns the maximum accepted delay in clock time between cluster members.

Returns:

the number of milliseconds representing the maximum accepted delay.

sendMessage

public boolean sendMessage(Serializable payload)

Sends a message of a given type across a cluster.

Parameters:

payload - the main body of the message; must not be null

Returns:

true if the send operation was successful, false otherwise

fromByteArray

protected Serializable fromByteArray(byte[] data,
                         ClassLoader classLoader)
                              throws IOException,
                                     ClassNotFoundException

Throws:

IOException

ClassNotFoundException