zeus.actors
Class ZeusTask

java.lang.Object
  java.lang.Thread
      zeus.actors.ZeusTask

All Implemented Interfaces:

java.lang.Runnable

public abstract class ZeusTask

extends java.lang.Thread

Tasks are generated in the form of 'stub' files, skeleton implementations that need to be realised by application specific program code - this code is linked to the agents through the methods of this interface. This approach enables new domain-specific functionality to be integrated with the automated created agent-specific code, without needing to modify the latter. < p> The class variables include several arrays of Fact objects, one of which passes information from agent to task, and another which stores the result of performing the task (which can then be read back by the agent when the task has completed running.

This is a crucially important class for developers who want to add their own application-specific functionality, and so should be studied carefully. Instructions and an example of how to write a task body are provided in Section 6 of Zeus Application Realisation Guide. TaskExternals have been available since Zeus 1.1 and allow customisation without editing the stubs - which is useful in terms of preserving your edited code in a separate file.

Field Summary

protected AgentContext	context
protected java.lang.String	desired_by
protected Fact[]	expInputArgs The information the task expects to receive, (as specified when the task was defined) this can be used to validate the inputArgs
protected Fact[]	expOutputArgs The information the task expects to return, (as specified when the task was defined) this can be used to validate the outputArgs
protected Fact[][]	inputArgs The information passed from the agent to the task, (a 2D array is used to enable multiple fact instances)
private boolean	isAborted
private boolean	isFinished
private boolean	isRunning
protected java.lang.String[]	media
protected Fact[][]	outputArgs The information returned from the task to the agent

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

protected

ZeusTask()

Method Summary

void	abort() Call this method in cases where the task terminates abnormally
protected abstract void	exec() This is the interface between the agent and the task; hence the body of the task should implement this method
java.lang.String	getDescription() This is the method called to get the string that describes this task in the service registration The concrete implementation is included to promote the smooth running of legacy agents
java.lang.String	getDesiredBy()
Fact[]	getExpectedInputArgs()
Fact[]	getExpectedOutputArgs()
Fact[][]	getInputArgs()
java.lang.String	getInstanceDetails() Get the instance details from the task.
Fact[][]	getOutputArgs()
boolean	isAborted()
boolean	isFinished()
boolean	isRunning()
void	run() Used internally by the ExecutionMonitor to start the task, users should not call this themselves
void	setContext(AgentContext context)
void	setDesiredBy(java.lang.String desired_by)
void	setExpectedInputArgs(Fact[] f)
void	setExpectedOutputArgs(Fact[] f)
void	setInputArgs(Fact[][] t)
void	setMedia(java.lang.String[] media)
void	setOutputArgs(Fact[] f)
void	setOutputArgs(Fact[][] f)

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

inputArgs

protected Fact[][] inputArgs

The information passed from the agent to the task, (a 2D array is used to enable multiple fact instances)

outputArgs

protected Fact[][] outputArgs

The information returned from the task to the agent

expInputArgs

protected Fact[] expInputArgs

The information the task expects to receive, (as specified when the task was defined) this can be used to validate the inputArgs

expOutputArgs

protected Fact[] expOutputArgs

The information the task expects to return, (as specified when the task was defined) this can be used to validate the outputArgs

media

protected java.lang.String[] media

isFinished

private boolean isFinished

isRunning

private boolean isRunning

isAborted

private boolean isAborted

desired_by

protected java.lang.String desired_by

context

protected AgentContext context

Constructor Detail

ZeusTask

protected ZeusTask()

Method Detail

setMedia

public void setMedia(java.lang.String[] media)

run

public void run()

Used internally by the ExecutionMonitor to start the task, users should not call this themselves

isRunning

public boolean isRunning()

isFinished

public boolean isFinished()

isAborted

public boolean isAborted()

abort

public void abort()

Call this method in cases where the task terminates abnormally

setContext

public void setContext(AgentContext context)

setInputArgs

public void setInputArgs(Fact[][] t)

setExpectedOutputArgs

public void setExpectedOutputArgs(Fact[] f)

setExpectedInputArgs

public void setExpectedInputArgs(Fact[] f)

setOutputArgs

public void setOutputArgs(Fact[] f)

setOutputArgs

public void setOutputArgs(Fact[][] f)

getInputArgs

public Fact[][] getInputArgs()

getExpectedOutputArgs

public Fact[] getExpectedOutputArgs()

getExpectedInputArgs

public Fact[] getExpectedInputArgs()

getOutputArgs

public Fact[][] getOutputArgs()

setDesiredBy

public void setDesiredBy(java.lang.String desired_by)

getDesiredBy

public java.lang.String getDesiredBy()

exec

protected abstract void exec()

This is the interface between the agent and the task; hence the body of the task should implement this method

getDescription

public java.lang.String getDescription()

This is the method called to get the string that describes this task in the service registration The concrete implementation is included to promote the smooth running of legacy agents

Since:

1.3

getInstanceDetails

public java.lang.String getInstanceDetails()

Get the instance details from the task. Returns null if not implemented by the sub class.