com.jcorporate.expresso.core.utility
Class JobHandler

java.lang.Object
  java.lang.Thread
      com.jcorporate.expresso.core.registry.ExpressoThread
          com.jcorporate.expresso.core.utility.JobHandler

All Implemented Interfaces:

Runnable

public class JobHandler

extends com.jcorporate.expresso.core.registry.ExpressoThread

The JobHandler is an object which runs constantly on the server side, looking periodically in a job queue for work to do. If it finds work to do, it spawns a new server object as specified in the queue. It may either wait for that object to complete or spawn it as a seperate thread, depending on setup options for the object being spawned

Author:

Michael Nash

Field Summary

protected static org.apache.log4j.Logger	log The log4j Logger
protected Crontab	m_cronMgr The crontab for this job handler
protected String	m_jobHandlerStatus Current handler status
protected long	m_serverID The server id
protected boolean	running Status flag for if the server is running
protected static Vector	serverList The list of JobHandler servers

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

JobHandler(String dbName)
Constructor

Method Summary

Crontab	getCronManager() Retrieve the crontab for this job handler.
long	getID() Retrieve the server id
Vector	getServerList() Return a list of current Job objects
String	getStatus() Useful for determining current state from the outside.
static void	main(String[] args) Main method so that JobHandler can be launched from a command line
void	registerJobHandler() Register JobHandler in the DataBase.
protected void	resetCurrentJobs() Marks all current running jobs as "Available"
static void	resetQ(String dbName) Resets any 'running' jobs on startup to available.
void	run() Main thread process of the JobHandler process
void	setDataContext(String newDBName) Sets the Job Handler's data context
void	setID(long num) Sets the Job Handler Id
void	shutDown() mark thread for shutdown and interrupt

Methods inherited from class com.jcorporate.expresso.core.registry.ExpressoThread

getThreadContext

Methods inherited from class java.lang.Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getContextClassLoader, getName, getPriority, getThreadGroup, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setName, setPriority, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Field Detail

serverList

protected static Vector serverList

The list of JobHandler servers

log

protected static final org.apache.log4j.Logger log

The log4j Logger

m_cronMgr

protected Crontab m_cronMgr

The crontab for this job handler

m_jobHandlerStatus

protected String m_jobHandlerStatus

Current handler status

running

protected boolean running

Status flag for if the server is running

m_serverID

protected long m_serverID

The server id

Constructor Detail

JobHandler

public JobHandler(String dbName)
           throws DBException,
                  ServerException

Constructor

Parameters:

dbName - The data context for this job handler to run in.

Throws:

DBException - If the database cannot be contacted

ServerException - If another uncaught exception occurs

Method Detail

setDataContext

public void setDataContext(String newDBName)

Sets the Job Handler's data context

Parameters:

newDBName - The new data context name

setID

public void setID(long num)

Sets the Job Handler Id

Parameters:

num - long integer.

getID

public long getID()

Retrieve the server id

Returns:

The Job Handler Server ID Number

getCronManager

public Crontab getCronManager()

Retrieve the crontab for this job handler. Excessive use of this function may not be threadsafe. Use only for necessary management of the cron handler and sychronize all modification acccess against the instance.

Returns:

Crontab instance.

getServerList

public Vector getServerList()
                     throws ServerException

Return a list of current Job objects

Returns:

Vector A list of the currently executing jobs

Throws:

ServerException - If the list cannot be obtained

main

public static void main(String[] args)

Main method so that JobHandler can be launched from a command line

Parameters:

args - Command line arguments to supply the information to connect to the database

resetQ

public static void resetQ(String dbName)
                   throws DBException

Resets any 'running' jobs on startup to available.

Parameters:

dbName - The data context to reset.

Throws:

DBException - upon error updating the appropriate fields

getStatus

public String getStatus()

Useful for determining current state from the outside. Not thread safe! Use it for debug purposes only, don't actually base decisions to start or stop the job handler based upon this.

Returns:

the current status code of the JobHandler.

registerJobHandler

public void registerJobHandler()

Register JobHandler in the DataBase.

run

public void run()

Main thread process of the JobHandler process

shutDown

public void shutDown()

mark thread for shutdown and interrupt

resetCurrentJobs

protected void resetCurrentJobs()
                         throws DBException

Marks all current running jobs as "Available"

Throws:

DBException - upon data access error