org.space4j.implementation
Class SimpleSpace4J

java.lang.Object
  org.space4j.implementation.SimpleSpace4J

All Implemented Interfaces:

java.lang.Runnable, Space4J

Direct Known Subclasses:

MasterSpace4J, SlaveSpace4J

public class SimpleSpace4J
extends java.lang.Object
implements Space4J, java.lang.Runnable

The simplest possible implementation of a Space4J.

Field Summary

protected java.lang.String	dirname
protected IndexManager	im
protected Logger	logger
protected long	snapTime
protected Space	space
protected java.lang.Thread	thread

Constructor Summary

SimpleSpace4J(java.lang.String dirname)

SimpleSpace4J(java.lang.String dirname, long snapTime)
Initializes the SimpleSpace4J, initializes the Logger, recover the Space from disk if there is a snapshot saved and reapply the commands to the Space.

Method Summary

int	exec(Command cmd) Execute a command and log it.
protected int	exec(Command cmd, boolean log)
void	executeSnapshot() Take a snapshot of the Space to disk.
java.lang.String	getDirName()
Space	getSpace() Returns the Space where the Objects are stored, so the client can direct access them.
Space	readSnapshot()
int	reapply(Command cmd) Re-apply a command on the underlying Space.
void	reapplyCommandsFromLog()
void	run()
void	start() Starts the Space4J.

Methods inherited from class java.lang.Object

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

Field Detail

space

protected Space space

logger

protected Logger logger

dirname

protected java.lang.String dirname

im

protected IndexManager im

thread

protected java.lang.Thread thread

snapTime

protected long snapTime

Constructor Detail

SimpleSpace4J

public SimpleSpace4J(java.lang.String dirname,
                     long snapTime)
              throws LoggerException,
                     CommandException

Initializes the SimpleSpace4J, initializes the Logger, recover the Space from disk if there is a snapshot saved and reapply the commands to the Space.

Throws:

LoggerException

CommandException

SimpleSpace4J

public SimpleSpace4J(java.lang.String dirname)
              throws LoggerException,
                     CommandException

Throws:

LoggerException

CommandException

Method Detail

getDirName

public java.lang.String getDirName()

getSpace

public Space getSpace()

Description copied from interface: Space4J

Returns the Space where the Objects are stored, so the client can direct access them.

Specified by:

getSpace in interface Space4J

Returns:

a Space if Space4J is running locally or null otherwise

run

public void run()

Specified by:

run in interface java.lang.Runnable

start

public void start()
           throws java.net.UnknownHostException,
                  java.io.IOException,
                  java.lang.ClassNotFoundException

Description copied from interface: Space4J

Starts the Space4J. This is only necessary for a replicated Space4J.

Specified by:

start in interface Space4J

Throws:

java.net.UnknownHostException

java.io.IOException

java.lang.ClassNotFoundException

exec

public int exec(Command cmd)
         throws CommandException,
                LoggerException

Execute a command and log it.

Specified by:

exec in interface Space4J

Parameters:

cmd - The command to be executed and logged.

Returns:

The number of objects modified by this operation.

Throws:

CommandException - if there is a problem executing this command

LoggerException - if there is a problem logging thie command

reapply

public int reapply(Command cmd)
            throws CommandException,
                   LoggerException

Description copied from interface: Space4J

Re-apply a command on the underlying Space. This method will be used to re-apply the commands from the logs. OBS: Logging is done AFTER the command is executed. If, for some reason, a CommandException is thrown, the command will not be logged.

Specified by:

reapply in interface Space4J

Parameters:

cmd - The command to execute.

Returns:

An int containing the number of objects modified by this operation.

Throws:

CommandException - if there is a problem executing this command

LoggerException - if there is a problem logging thie command

exec

protected int exec(Command cmd,
                   boolean log)
            throws CommandException,
                   LoggerException

Throws:

CommandException

LoggerException

executeSnapshot

public void executeSnapshot()
                     throws LoggerException

Description copied from interface: Space4J

Take a snapshot of the Space to disk. The Space will be serialized and written to disk.

Specified by:

executeSnapshot in interface Space4J

Throws:

LoggerException

readSnapshot

public Space readSnapshot()
                   throws LoggerException

Throws:

LoggerException

reapplyCommandsFromLog

public void reapplyCommandsFromLog()
                            throws CommandException,
                                   LoggerException

Throws:

CommandException

LoggerException