org.sapia.ubik.rmi.replication
Class ReplicatedCommand

java.lang.Object
  org.sapia.ubik.rmi.server.command.Command
      org.sapia.ubik.rmi.server.RMICommand
          org.sapia.ubik.rmi.server.invocation.InvokeCommand
              org.sapia.ubik.rmi.replication.ReplicatedCommand

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable, Executable

Direct Known Subclasses:

ReplicatedCommandEx

public abstract class ReplicatedCommand
extends InvokeCommand

Wraps an InvokeCommand that is intented to be replicated to the different servers in a domain or cluster.

Author:

Yanick Duchesne

Copyright:

Copyright © 2002-2004 Sapia Open Source Software. All Rights Reserved.

License:

Read the license.txt file of the jar or visit the license page at the Sapia OSS web site

See Also:

#getReplicationContext(), Serialized Form

Field Summary

Fields inherited from class org.sapia.ubik.rmi.server.RMICommand

_config, _vmId

Constructor Summary

ReplicatedCommand()
Do not call; used for externalization only.

ReplicatedCommand(InvokeCommand cmd, java.util.Set targets, ReplicatedInvoker invoker, boolean synchronous)

Method Summary

void	disable() Disables replication behavior (this command will execute as a normal InvokeCommand).
java.lang.Object	execute() This method's implementation internally calls the getReplicationContext() method.
ReplicatedInvoker	getReplicatedInvoker()
protected java.util.Set	getTargetAddresses()
protected java.util.Set	getVisitedAddresses()
void	readExternal(java.io.ObjectInput in)
protected java.lang.Object	send(ServerAddress next) This method synchronously or asynchronously sends this instance to the server at the given address.
void	writeExternal(java.io.ObjectOutput out)

Methods inherited from class org.sapia.ubik.rmi.server.invocation.InvokeCommand

convertParams, getMethodName, getOID, getParameterTypes, getParams, setParams, usesMarshalledObjects

Methods inherited from class org.sapia.ubik.rmi.server.RMICommand

getConnection, getServerAddress, getVmId, init

Methods inherited from class java.lang.Object

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

Constructor Detail

ReplicatedCommand

public ReplicatedCommand()

Do not call; used for externalization only.

ReplicatedCommand

public ReplicatedCommand(InvokeCommand cmd,
                         java.util.Set targets,
                         ReplicatedInvoker invoker,
                         boolean synchronous)

Parameters:

cmd - the InvokeCommand to replicate.

targets - the Set of ServerAddresses that are targeted by the command. If null, then all siblings will be targeted.

invoker - the ReplicatedInvoker implementation in charge of performing replicated method invocations.

Method Detail

execute

public java.lang.Object execute()
                         throws java.lang.Throwable

This method's implementation internally calls the getReplicationContext() method. The returned ReplicationContext is used as a hook to the server in which this command is executed. Internally, the method selects the next server to which this instance should be dispatched, and executes the command that this instance wraps.

If the execution is successful, this instance is dispatched by means of the ReplicationContext.

Specified by:

execute in interface Executable

Overrides:

execute in class InvokeCommand

Returns:

any value returned by this method.

Throws:

java.lang.Throwable - if an error occurs while executing this command

See Also:

#getReplicationContext(), RMICommand.execute()

getReplicatedInvoker

public ReplicatedInvoker getReplicatedInvoker()

Returns:

the ReplicatedInvoker that this instance holds.

disable

public void disable()

Disables replication behavior (this command will execute as a normal InvokeCommand).

readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException

Specified by:

readExternal in interface java.io.Externalizable

Overrides:

readExternal in class InvokeCommand

Throws:

java.io.IOException

java.lang.ClassNotFoundException

See Also:

InvokeCommand.readExternal(java.io.ObjectInput)

writeExternal

public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException

Specified by:

writeExternal in interface java.io.Externalizable

Overrides:

writeExternal in class InvokeCommand

Throws:

java.io.IOException

See Also:

InvokeCommand.writeExternal(java.io.ObjectOutput)

send

protected java.lang.Object send(ServerAddress next)
                         throws java.rmi.RemoteException

This method synchronously or asynchronously sends this instance to the server at the given address.

Parameters:

next - the ServerAddress of the "next" server to which this instance should be sent.

Returns:

the result of the invocation.

Throws:

java.rmi.RemoteException - if a problem occurs sending this instance.

getVisitedAddresses

protected java.util.Set getVisitedAddresses()

getTargetAddresses

protected java.util.Set getTargetAddresses()