net.sf.basedb.clients.jobagent.executors
Class ProcessJobExecutor

java.lang.Object
  net.sf.basedb.clients.jobagent.executors.ProcessJobExecutor

All Implemented Interfaces:

JobExecutor

public class ProcessJobExecutor
extends Object
implements JobExecutor

This is a job executor which starts a new process for each job to be executed. This has the advantage that a misbehaving job can't interfere with other jobs or the job agent. For example, a call to System.exit(int) would only result in the job's process getting killed. Other jobs and the job agent would not be affected. Another advantage is that it makes it possible to apply a security policy to the new process for plugins that are not trusted with full access to the computer. See PluginDefinition.isTrusted().

The disadvantage is the overhead in time and memory of starting a new process.

Configuration parameter	Default value	Description
agent.executor.process.java		Path to the java executable to use. not specified the envoronment variable JAVA_HOME is used if it exists. Otherwise we let the operating system find the java command.
agent.executor.process.options	-server	Extra command line options to pass to the java executable: java <options> -cp ... className ....

Version:

2.0

Author:

nicklas

Last modified

$Date: 2010-09-02 14:09:15 +0200 (Thu, 02 Sep 2010) $

Nested Class Summary

static class

ProcessJobExecutor.StreamRedirector Used for redirecting standard output to a string.

Field Summary

private String	javaBin
private static Logger	log Log job agent events.
private String	options
private SignalHandler	signalHandler
private SignalReceiver	signalReceiver

Constructor Summary

ProcessJobExecutor()

Method Summary

void	close() This method is called at when the agent is stopped or paused.
void	executeJob(SessionControl sc, Agent agent, Job job, JobAgentSettings settings, Job.ExecutionTime usedSlot) Execute the specified job.
void	init(Agent agent) Initialize the job executor.

Methods inherited from class java.lang.Object

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

Field Detail

log

private static final Logger log

Log job agent events.

javaBin

private String javaBin

options

private String options

signalReceiver

private SignalReceiver signalReceiver

signalHandler

private SignalHandler signalHandler

Constructor Detail

ProcessJobExecutor

public ProcessJobExecutor()

Method Detail

init

public void init(Agent agent)

Description copied from interface: JobExecutor

Initialize the job executor. This method is called once immediately after the object has been created.

Specified by:

init in interface JobExecutor

Parameters:

agent - The agent

executeJob

public void executeJob(SessionControl sc,
                       Agent agent,
                       Job job,
                       JobAgentSettings settings,
                       Job.ExecutionTime usedSlot)

Description copied from interface: JobExecutor

Execute the specified job. This method is called in a new thread created specifically for running that job. If the agent is shutting down it will send an interrupt signal to all job threads. It is up to the job executor to decide how to handle this. It may either decide to kill the job or let it continue as if nothing happened.

The job sent to this method has it's status set to Job.Status.PREPARED. The implementation of this method must change the status to either Job.Status.DONE or Job.Status.ERROR. If the status hasn't changed the job agent will set the status to signal an unknown error.

Specified by:

executeJob in interface JobExecutor

Parameters:

sc - A SessionControl where the owner of the job is logged in and the correct active project is set

agent - The agent that sent the request to execute the job

job - The job to execute

settings - The specific settings used for the plugin on this job agent or null if no settings has been specified

usedSlot - The slot that was used to execut the job

close

public void close()

Description copied from interface: JobExecutor

This method is called at when the agent is stopped or paused. No more execution requests will be sent to the current job executor, but running jobs should NOT be terminated due to this method beeing called.

Specified by:

close in interface JobExecutor