org.sapia.ubik.rmi.server
Class RMICommand

java.lang.Object
  org.sapia.ubik.rmi.server.command.Command
      org.sapia.ubik.rmi.server.RMICommand

All Implemented Interfaces:

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

Direct Known Subclasses:

CommandConnect, CommandGc, CommandPing, CommandRefer, HelloWorldCommand, InvokeCommand, RMICommandProcessor.ResponseListCommand

public abstract class RMICommand
extends Command
implements java.io.Externalizable

This class models an executable command. Typically, a command object is created on the client side, then sent to the server where it is executed.

Author:

Yanick Duchesne

Copyright:

Copyright © 2002-2003 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:

Serialized Form

Field Summary

protected Config	_config
protected VmId	_vmId

Constructor Summary

RMICommand()

Method Summary

abstract java.lang.Object	execute() Executes this command.
Connection	getConnection() Returns this command's connection.
ServerAddress	getServerAddress() Returns this command's target server address, which corresponds to the server that received this command.
VmId	getVmId() Returns the identifier of the VM from which this command comes from.
void	init(Config config) Initializes this instance with a CommandConfig upon its arrival at the server.
void	readExternal(java.io.ObjectInput in)
void	writeExternal(java.io.ObjectOutput out)

Methods inherited from class java.lang.Object

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

Field Detail

_config

protected transient Config _config

_vmId

protected VmId _vmId

Constructor Detail

RMICommand

public RMICommand()

Method Detail

init

public void init(Config config)

Initializes this instance with a CommandConfig upon its arrival at the server. It is a server's responsability to call this method once it receives a command.

When overriding this method, super.init(config) must be called. If a command nests another one, it should also call init() on the nested command.

Parameters:

config - CommandConfig

getVmId

public VmId getVmId()

Returns the identifier of the VM from which this command comes from.

Returns:

a VmId.

getServerAddress

public ServerAddress getServerAddress()

Returns this command's target server address, which corresponds to the server that received this command.

Returns:

this command's ServerAddress

getConnection

public final Connection getConnection()

Returns this command's connection.

Returns:

a Connection

execute

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

Executes this command.

Specified by:

execute in interface Executable

Specified by:

execute in class Command

Returns:

any value returned by this method.

Throws:

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

readExternal

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

Specified by:

readExternal in interface java.io.Externalizable

Throws:

java.io.IOException

java.lang.ClassNotFoundException

See Also:

Externalizable.readExternal(ObjectInput)

writeExternal

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

Specified by:

writeExternal in interface java.io.Externalizable

Throws:

java.io.IOException

See Also:

Externalizable.writeExternal(ObjectOutput)