net.sf.asyncobjects.vats
Class VatRunner

java.lang.Object
  net.sf.asyncobjects.vats.VatRunner

All Implemented Interfaces:

VatFactory

Direct Known Subclasses:

ExecutorRunner, VatQueueRunner

public abstract class VatRunner
extends Object
implements VatFactory

This is a base class for vat runners. The vat is a just an event queue. The vat runner actually executes the events. The vat has a single runner, however runners support multiple vats.

While vat runner is aware about the current vat, it does not keeps track of vats that is running.

The runner might provide additional services to the vats it is hosting. So vats might check if the runner belong to some specific subclass to obtain these services.

Author:

const

Nested Class Summary

static class

VatRunner.VatRunnerState Vat state

Field Summary

protected VatRunner.VatRunnerState	state a state of vat runner
protected Object	stateLock a state lock

Constructor Summary

VatRunner()

Method Summary

protected void	cancelledEqueuedVat(Vat vat, Object ticket) This method cancels enquued vat and detaches it from runner.
int	getBachingFactor()
VatRunner.VatRunnerState	getState()
protected abstract boolean	hasEvents(Vat vat, Object ticket) This method is called by the vat when new events have arrived.
Vat	newVat() Create default vat for this runner.
Vat	newVat(String name) Create default vat for this runner
void	setBachingFactor(int bachingFactor) Set batching factor
protected void	setStarted() Set state to started
protected void	setStarting() Set state to starting
protected void	setState(VatRunner.VatRunnerState state)
protected void	setStopped() Set stopped state
protected void	setStopping() Set stoppong state

Methods inherited from class java.lang.Object

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

Field Detail

state

protected VatRunner.VatRunnerState state

a state of vat runner

stateLock

protected Object stateLock

a state lock

Constructor Detail

VatRunner

public VatRunner()

Method Detail

getBachingFactor

public int getBachingFactor()

Returns:

the bachingFactor

setBachingFactor

public void setBachingFactor(int bachingFactor)

Set batching factor

Parameters:

bachingFactor - the baching factor to set

hasEvents

protected abstract boolean hasEvents(Vat vat,
                                     Object ticket)

This method is called by the vat when new events have arrived. This method should never block and to be as fast as possible. This method executed within synchronoization over Vat's state lock. The vat enqueues itself only if is not running or enqueued yet.

Parameters:

vat - a vat that has new events and is associated with the runner

ticket - a ticket from the vat

Returns:

true if runner accpets the vat, false otherwise (happens if runner is stopped or is stopping)

cancelledEqueuedVat

protected final void cancelledEqueuedVat(Vat vat,
                                         Object ticket)

This method cancels enquued vat and detaches it from runner. The vat must be in equeued or idle state. This method is called when runner is unable to honor already accepted enqueue request.

Parameters:

vat - a vat

ticket - a ticket

Throws:

IllegalArgumentException - if vat is not attached to this runner or ticket do not match.

setStarted

protected void setStarted()

Set state to started

setStarting

protected void setStarting()

Set state to starting

setStopped

protected void setStopped()

Set stopped state

setStopping

protected void setStopping()

Set stoppong state

getState

public VatRunner.VatRunnerState getState()

Returns:

the state

setState

protected void setState(VatRunner.VatRunnerState state)

Parameters:

state - the state to set

newVat

public Vat newVat(String name)

Create default vat for this runner

Specified by:

newVat in interface VatFactory

Parameters:

name - a vat name

Returns:

a vat

newVat

public Vat newVat()

Create default vat for this runner. It passes null as to name of the vat causing default name generation.

Specified by:

newVat in interface VatFactory

Returns:

a vat