org.objectweb.cjdbc.controller.loadbalancer.tasks
Class AbstractTask

java.lang.Object
  org.objectweb.cjdbc.controller.loadbalancer.tasks.AbstractTask

Direct Known Subclasses:

BeginTask, CommitTask, KillThreadTask, ReadStoredProcedureTask, RollbackTask, SelectRequestTask, WriteRequestTask, WriteRequestWithKeysTask, WriteStoredProcedureTask

public abstract class AbstractTask

extends java.lang.Object

Defines an abstract task to be processed by a BackendWorkerThread.

Version:

1.0

Author:

Emmanuel Cecchet

Field Summary

private java.util.ArrayList	exceptions
private int	failed
private int	nbToComplete Number of threads that must succeed before returning.
private int	success
private int	totalNb Total number of threads.

Constructor Summary

AbstractTask(int nbToComplete, int totalNb)
Sets the number of threads among the total number of threads that must successfully complete the execution of this AbstractTask before returning.

Method Summary

abstract void	execute(BackendWorkerThread backendThread) The task code to be executed by backendThread.
java.util.ArrayList	getExceptions() Returns the exceptions lists.
int	getFailed() Returns the failed.
int	getNbToComplete() Returns the number of threads that must succeed before returning.
int	getSuccess() Returns the success.
int	getTotalNb() Returns the total number of threads.
boolean	notifyFailure(BackendWorkerThread backendThread, long timeout, java.sql.SQLException e) Notifies that the specified backendThread failed to execute this task.
void	notifySuccess() Notifies the successful completion of this task.
void	setTotalNb(int totalNb) Sets the total number of threads.

Methods inherited from class java.lang.Object

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

Field Detail

totalNb

private int totalNb

Total number of threads.

nbToComplete

private int nbToComplete

Number of threads that must succeed before returning.

success

private int success

failed

private int failed

exceptions

private java.util.ArrayList exceptions

Constructor Detail

AbstractTask

public AbstractTask(int nbToComplete,
                    int totalNb)

Sets the number of threads among the total number of threads that must successfully complete the execution of this AbstractTask before returning.

Parameters:

nbToComplete - number of threads that must succeed before returning

totalNb - total number of threads

Method Detail

execute

public abstract void execute(BackendWorkerThread backendThread)
                      throws java.sql.SQLException

The task code to be executed by backendThread.

Parameters:

backendThread - The backend thread executing this task

Throws:

java.sql.SQLException - if an error occurs

notifySuccess

public void notifySuccess()

Notifies the successful completion of this task.

notifyFailure

public boolean notifyFailure(BackendWorkerThread backendThread,
                             long timeout,
                             java.sql.SQLException e)
                      throws java.sql.SQLException

Notifies that the specified backendThread failed to execute this task. If all nodes failed, this method return false meaning that the problem was due to the task and not to the thread. If the method returns true, it can mean that this thread failed and is no more coherent, therefore the backend associated to this thread should be disabled.

Parameters:

backendThread - the backend thread that has failed

timeout - time in milliseconds to wait for other threads to signal success or failure

e - the exception causing the failure

Returns:

true if at least one node succeeded to execute this task, false if all threads failed

Throws:

java.sql.SQLException - if an error occured in the notification process

getExceptions

public java.util.ArrayList getExceptions()

Returns the exceptions lists.

Returns:

an ArrayList

getFailed

public int getFailed()

Returns the failed.

Returns:

an int value

getNbToComplete

public int getNbToComplete()

Returns the number of threads that must succeed before returning.

Returns:

an int value

getSuccess

public int getSuccess()

Returns the success.

Returns:

an int value

getTotalNb

public int getTotalNb()

Returns the total number of threads.

Returns:

an int value

See Also:

setTotalNb(int)

setTotalNb

public void setTotalNb(int totalNb)

Sets the total number of threads.

Parameters:

totalNb - the total number of threads to set

See Also:

getTotalNb()