org.exoplatform.services.rpc.impl

Class AbstractRPCService

java.lang.Object

org.exoplatform.services.rpc.impl.AbstractRPCService

All Implemented Interfaces:

RPCService, org.jgroups.blocks.RequestHandler, org.jgroups.MembershipListener, Startable

Direct Known Subclasses:

RPCServiceImpl

public abstract class AbstractRPCService
extends Object
implements RPCService, Startable, org.jgroups.blocks.RequestHandler, org.jgroups.MembershipListener

This class is a basic implementation of the RPCService, it is mainly based on the MessageDispatcher of JGroups. This implementation is not designed to give the best possible performances, it only aims to give a way to communicate with other nodes.

Version:

$Id$

Author:

Nicolas Filotto

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	AbstractRPCService.MemberHasLeftException
static class	AbstractRPCService.MessageBody This intern class will be used to
static class	AbstractRPCService.State All the potential states of the RPCServiceImpl

Field Summary

Fields

Modifier and Type	Field and Description
protected org.jgroups.Channel	channel The JGroups Channel used to communicate with other nodes
protected static String	CLUSTER_NAME The default value of the cluster name
protected org.jgroups.conf.ProtocolStackConfigurator	configurator The configurator used to create the JGroups Channel
protected org.jgroups.Address	coordinator The address of the current coordinator
protected static int	DEFAULT_RETRY_TIMEOUT The value of the default retry timeout
protected static int	DEFAULT_TIMEOUT The value of the default timeout
protected org.jgroups.blocks.MessageDispatcher	dispatcher The dispatcher used to launch the command of the cluster nodes
protected boolean	isCoordinator Indicates whether the current node is the coordinator of the cluster or not
protected List<org.jgroups.Address>	members The current list of all the members of the cluster
protected static String	PARAM_ALLOW_FAILOVER The name of the parameter to allow the failover
protected static String	PARAM_CLUSTER_NAME The name of the parameter for the name of the cluster.
protected static String	PARAM_DEFAULT_TIMEOUT The name of the parameter for the default timeout
protected static String	PARAM_JGROUPS_CONFIG The name of the parameter for the location of the JGroups configuration.
protected static String	PARAM_RETRY_TIMEOUT The name of the parameter for the retry timeout

Fields inherited from interface org.exoplatform.services.rpc.RPCService

ACCESS_RPC_SERVICE_PERMISSION

Constructor Summary

Constructors

Constructor and Description
AbstractRPCService(ExoContainerContext ctx, InitParams params, ConfigurationManager configManager) The public constructor

Method Summary

Modifier and Type	Method and Description
void	block()
protected abstract org.jgroups.util.RspList	castMessage(List<org.jgroups.Address> dests, org.jgroups.Message msg, boolean synchronous, long timeout) Cast a message to all the given members
protected abstract org.jgroups.Channel	createChannel() Create a channel
protected List<Object>	excecuteCommand(List<org.jgroups.Address> dests, RemoteCommand command, boolean synchronous, long timeout, Serializable... args) Execute the command on all the nodes corresponding to the list of destinations.
List<Object>	executeCommandOnAllNodes(RemoteCommand command, boolean synchronous, Serializable... args) Executes a command on all the cluster nodes.
List<Object>	executeCommandOnAllNodes(RemoteCommand command, long timeout, Serializable... args) Executes a command synchronously on all the cluster nodes.
protected List<Object>	executeCommandOnAllNodesMain(RemoteCommand command, boolean synchronous, long timeout, Serializable... args) Executes a command on all the cluster nodes.
Object	executeCommandOnCoordinator(RemoteCommand command, boolean synchronous, Serializable... args) Executes a command on the coordinator only.
Object	executeCommandOnCoordinator(RemoteCommand command, long timeout, Serializable... args) Executes a command synchronously on the coordinator only.
protected Object	executeCommandOnCoordinatorMain(RemoteCommand command, boolean synchronous, long timeout, Serializable... args) Executes a command on the coordinator only.
protected String	getClusterName() Gives the name of the cluster
protected RemoteCommand	getCommand(String commandId) Gives the RemoteCommand corresponding to the given id
protected long	getDefaultTimeout() Gives the value of the default timeout
protected abstract org.jgroups.Address	getLocalAddress() Returns the channel's own address.
protected abstract List<org.jgroups.Address>	getMembers(org.jgroups.View view) Returns a reference to the List of members (ordered) Do NOT change this list, hence your will invalidate the view Make a copy if you have to modify it.
protected long	getRetryTimeout() Gives the value of the retry timeout
Object	handle(org.jgroups.Message msg)
protected boolean	isAllowFailover() Indicates whether the failover capabilities are enabled or not
boolean	isCoordinator() Indicates whether the local node is the coordinator of the cluster
RemoteCommand	registerCommand(RemoteCommand command) Register a new RemoteCommand instance, it will be mapped to its id.
void	registerTopologyChangeListener(TopologyChangeListener listener) Register a new TopologyChangeListener
protected abstract void	setObject(org.jgroups.Message m, Object o) Takes an object and uses Java serialization to generate the byte[] buffer which is set in the message.
void	start()
void	stop()
void	suspect(org.jgroups.Address suspectedMbr)
void	unregisterCommand(RemoteCommand command) Unregister a RemoteCommand instance, if the id is known or the instance itself is known otherwise it will be ignored
void	unregisterTopologyChangeListener(TopologyChangeListener listener) Unregister a TopologyChangeListener if it exists
void	viewAccepted(org.jgroups.View view)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jgroups.MembershipListener

unblock

Field Detail

PARAM_JGROUPS_CONFIG

protected static final String PARAM_JGROUPS_CONFIG

The name of the parameter for the location of the JGroups configuration.

See Also:

Constant Field Values

PARAM_CLUSTER_NAME

protected static final String PARAM_CLUSTER_NAME

The name of the parameter for the name of the cluster.

See Also:

Constant Field Values

PARAM_DEFAULT_TIMEOUT

protected static final String PARAM_DEFAULT_TIMEOUT

The name of the parameter for the default timeout

See Also:

Constant Field Values

PARAM_ALLOW_FAILOVER

protected static final String PARAM_ALLOW_FAILOVER

The name of the parameter to allow the failover

See Also:

Constant Field Values

PARAM_RETRY_TIMEOUT

protected static final String PARAM_RETRY_TIMEOUT

The name of the parameter for the retry timeout

See Also:

Constant Field Values

DEFAULT_TIMEOUT

protected static final int DEFAULT_TIMEOUT

The value of the default timeout

See Also:

Constant Field Values

DEFAULT_RETRY_TIMEOUT

protected static final int DEFAULT_RETRY_TIMEOUT

The value of the default retry timeout

See Also:

Constant Field Values

CLUSTER_NAME

protected static final String CLUSTER_NAME

The default value of the cluster name

See Also:

Constant Field Values

configurator

protected final org.jgroups.conf.ProtocolStackConfigurator configurator

The configurator used to create the JGroups Channel

channel

protected org.jgroups.Channel channel

The JGroups Channel used to communicate with other nodes

members

protected volatile List<org.jgroups.Address> members

The current list of all the members of the cluster

coordinator

protected volatile org.jgroups.Address coordinator

The address of the current coordinator

isCoordinator

protected volatile boolean isCoordinator

Indicates whether the current node is the coordinator of the cluster or not

dispatcher

protected org.jgroups.blocks.MessageDispatcher dispatcher

The dispatcher used to launch the command of the cluster nodes

Constructor Detail

AbstractRPCService

public AbstractRPCService(ExoContainerContext ctx,
                          InitParams params,
                          ConfigurationManager configManager)

The public constructor

Parameters:

ctx - the ExoContainerContext from which we will extract the corresponding ExoContainer

params - the list of initial parameters

configManager - the configuration manager used to get the configuration of JGroups

Method Detail

executeCommandOnAllNodes

public List<Object> executeCommandOnAllNodes(RemoteCommand command,
                                             boolean synchronous,
                                             Serializable... args)
                                      throws RPCException

Executes a command on all the cluster nodes. This method is equivalent to the other method of the same type but with the default timeout. The command must be registered first otherwise an RPCException will be thrown.

Specified by:

executeCommandOnAllNodes in interface RPCService

Parameters:

command - The command to execute on each cluster node

synchronous - if true, sets group request mode to org.jgroups.blocks.GroupRequest#GET_ALL, and if false sets it to org.jgroups.blocks.GroupRequest#GET_NONE.

args - an array of Serializable objects corresponding to parameters of the command to execute remotely

Returns:

a list of responses from all the members of the cluster. If we met an exception on a given node, the RPCException will be the corresponding response of this particular node

Throws:

RPCException - in the event of problems.

executeCommandOnAllNodes

public List<Object> executeCommandOnAllNodes(RemoteCommand command,
                                             long timeout,
                                             Serializable... args)
                                      throws RPCException

Executes a command synchronously on all the cluster nodes. The command must be registered first otherwise an RPCException will be thrown.

Specified by:

executeCommandOnAllNodes in interface RPCService

Parameters:

command - The command to execute on each cluster node

timeout - a timeout after which to throw a replication exception.

args - an array of Serializable objects corresponding to parameters of the command to execute remotely

Returns:

a list of responses from all the members of the cluster. If we met an exception on a given node, the RPCException will be the corresponding response of this particular node

Throws:

RPCException - in the event of problems.

executeCommandOnAllNodesMain

protected List<Object> executeCommandOnAllNodesMain(RemoteCommand command,
                                                    boolean synchronous,
                                                    long timeout,
                                                    Serializable... args)
                                             throws RPCException

Executes a command on all the cluster nodes. This method is equivalent to the other method of the same type but with the default timeout. The command must be registered first otherwise an RPCException will be thrown.

Parameters:

command - The command to execute on each cluster node

synchronous - if true, sets group request mode to org.jgroups.blocks.GroupRequest#GET_ALL, and if false sets it to org.jgroups.blocks.GroupRequest#GET_NONE.

timeout - a timeout after which to throw a replication exception.

args - an array of Serializable objects corresponding to parameters of the command to execute remotely

Returns:

a list of responses from all the members of the cluster. If we met an exception on a given node, the RPCException will be the corresponding response of this particular node

Throws:

RPCException - in the event of problems.

executeCommandOnCoordinator

public Object executeCommandOnCoordinator(RemoteCommand command,
                                          boolean synchronous,
                                          Serializable... args)
                                   throws RPCException

Executes a command on the coordinator only. This method is equivalent to the other method of the same type but with the default timeout. The command must be registered first otherwise an RPCException will be thrown.

Specified by:

executeCommandOnCoordinator in interface RPCService

Parameters:

command - The command to execute on the coordinator node

synchronous - if true, sets group request mode to org.jgroups.blocks.GroupRequest#GET_ALL, and if false sets it to org.jgroups.blocks.GroupRequest#GET_NONE.

args - an array of Serializable objects corresponding to parameters of the command to execute remotely

Returns:

the response of the coordinator.

Throws:

RPCException - in the event of problems.

executeCommandOnCoordinator

public Object executeCommandOnCoordinator(RemoteCommand command,
                                          long timeout,
                                          Serializable... args)
                                   throws RPCException

Executes a command synchronously on the coordinator only. The command must be registered first otherwise an RPCException will be thrown.

Specified by:

executeCommandOnCoordinator in interface RPCService

Parameters:

command - The command to execute on the coordinator node

timeout - a timeout after which to throw a replication exception.

args - an array of Serializable objects corresponding to parameters of the command to execute remotely

Returns:

the response of the coordinator.

Throws:

RPCException - in the event of problems.

executeCommandOnCoordinatorMain

protected Object executeCommandOnCoordinatorMain(RemoteCommand command,
                                                 boolean synchronous,
                                                 long timeout,
                                                 Serializable... args)
                                          throws RPCException

Executes a command on the coordinator only. This method is equivalent to the other method of the same type but with the default timeout. The command must be registered first otherwise an RPCException will be thrown.

Parameters:

command - The command to execute on the coordinator node

synchronous - if true, sets group request mode to org.jgroups.blocks.GroupRequest#GET_ALL, and if false sets it to org.jgroups.blocks.GroupRequest#GET_NONE.

timeout - a timeout after which to throw a replication exception.

args - an array of Serializable objects corresponding to parameters of the command to execute remotely

Returns:

the response of the coordinator.

Throws:

RPCException - in the event of problems.

excecuteCommand

protected List<Object> excecuteCommand(List<org.jgroups.Address> dests,
                                       RemoteCommand command,
                                       boolean synchronous,
                                       long timeout,
                                       Serializable... args)
                                throws RPCException

Execute the command on all the nodes corresponding to the list of destinations.

Parameters:

dests - the list of members on which the command needs to be executed

command - the command to execute

synchronous - if true, sets group request mode to org.jgroups.blocks.GroupRequest#GET_ALL, and if false sets it to org.jgroups.blocks.GroupRequest#GET_NONE.

timeout - a timeout after which to throw a replication exception.

args - the list of parameters

Returns:

a list of responses from all the targeted members of the cluster.

Throws:

RPCException - in the event of problems.

handle

public Object handle(org.jgroups.Message msg)

Specified by:

handle in interface org.jgroups.blocks.RequestHandler

block

public void block()

Specified by:

block in interface org.jgroups.MembershipListener

suspect

public void suspect(org.jgroups.Address suspectedMbr)

Specified by:

suspect in interface org.jgroups.MembershipListener

viewAccepted

public void viewAccepted(org.jgroups.View view)

Specified by:

viewAccepted in interface org.jgroups.MembershipListener

registerCommand

public RemoteCommand registerCommand(RemoteCommand command)

Register a new RemoteCommand instance, it will be mapped to its id. If a command with the same Id has already been registered, a warning will be printed into the log file and the new command will replace the old one.

Specified by:

registerCommand in interface RPCService

Parameters:

command - the instance of the RemoteCommand to register

Returns:

the command itself if it could be registered null otherwise

unregisterCommand

public void unregisterCommand(RemoteCommand command)

Unregister a RemoteCommand instance, if the id is known or the instance itself is known otherwise it will be ignored

Specified by:

unregisterCommand in interface RPCService

Parameters:

command - the command to unregister

isCoordinator

public boolean isCoordinator()
                      throws RPCException

Indicates whether the local node is the coordinator of the cluster

Specified by:

isCoordinator in interface RPCService

Returns:

true if the coordinator is the coordinator, false otherwise throws RPCException in case the RPCService is in an illegal state

Throws:

RPCException

registerTopologyChangeListener

public void registerTopologyChangeListener(TopologyChangeListener listener)
                                    throws SecurityException

Register a new TopologyChangeListener

Specified by:

registerTopologyChangeListener in interface RPCService

Parameters:

listener - the listener to be registered

Throws:

SecurityException - if the SecurityManager is installed and the call method doesn't have the RuntimePermission ACCESS_RPC_SERVICE_PERMISSION

unregisterTopologyChangeListener

public void unregisterTopologyChangeListener(TopologyChangeListener listener)
                                      throws SecurityException

Unregister a TopologyChangeListener if it exists

Specified by:

unregisterTopologyChangeListener in interface RPCService

Parameters:

listener - the listener to unregister

Throws:

SecurityException - if the SecurityManager is installed and the call method doesn't have the RuntimePermission ACCESS_RPC_SERVICE_PERMISSION

getCommand

protected RemoteCommand getCommand(String commandId)

Gives the RemoteCommand corresponding to the given id

Parameters:

commandId - the command id of the command to retrieve

Returns:

the corresponding RemoteCommand

start

public void start()

Specified by:

start in interface Startable

stop

public void stop()

Specified by:

stop in interface Startable

getDefaultTimeout

protected long getDefaultTimeout()

Gives the value of the default timeout

Returns:

the default timeout

getClusterName

protected String getClusterName()

Gives the name of the cluster

Returns:

the name of the cluster

getRetryTimeout

protected long getRetryTimeout()

Gives the value of the retry timeout

Returns:

the value of the retry timeout

isAllowFailover

protected boolean isAllowFailover()

Indicates whether the failover capabilities are enabled or not

Returns:

true if the failover capabilities are allowed, false otherwise

getLocalAddress

protected abstract org.jgroups.Address getLocalAddress()

Returns the channel's own address. The result of calling this method on an unconnected channel is implementation defined (may return null). Calling this method on a closed channel returns null. Successor to #getAddress(). Addresses can be used as destination in the send() operation.

Returns:

The channel's address (opaque) or null if it cannot be found

castMessage

protected abstract org.jgroups.util.RspList castMessage(List<org.jgroups.Address> dests,
                                                        org.jgroups.Message msg,
                                                        boolean synchronous,
                                                        long timeout)
                                                 throws Exception

Cast a message to all the given members

Parameters:

dests - The members to which the message is to be sent.

msg - The message to be sent to the members.

synchronous - Indicates whether the message must be sent in synchronous or asynchronous mode.

timeout - If 0: wait forever. Otherwise, wait for responses or timeout time.

Returns:

A list of responses. Each response is an Object and associated to its sender.

Throws:

Exception - if any error occur while casting the message

createChannel

protected abstract org.jgroups.Channel createChannel()
                                              throws Exception

Create a channel

Returns:

An initialized channel

Throws:

Exception - if any error occur while creating the channel

getMembers

protected abstract List<org.jgroups.Address> getMembers(org.jgroups.View view)

Returns a reference to the List of members (ordered) Do NOT change this list, hence your will invalidate the view Make a copy if you have to modify it.

Returns:

a reference to the ordered list of members in this view

setObject

protected abstract void setObject(org.jgroups.Message m,
                                  Object o)

Takes an object and uses Java serialization to generate the byte[] buffer which is set in the message.