xdc.services.getset
Class Group

java.lang.Object
  xdc.services.getset.Group

public class Group
extends java.lang.Object

A group of Fxns that are executed atomically. When any one of them runs, the others are given a chance to run before anything else happens. Allows atomic updates among a group of related fields, so that code outside the Group should never see any inconsistency.

Within each Group the Fxns execute one at a time. Even if a Fxn makes changes that will cause another Fxn in the Group to run, that won't happen until after the first Fxn completes.

Constructor Summary

Group()
Create a new Group governed by the given scheduler

Method Summary

Fxn	add(Fxn fxn) Add a new Fxn to the group, and execute it once.
AutoFxn	addAuto(org.mozilla.javascript.Callable body) Wrap the given function body as an AutoFxn and add it to the group.
void	addStale(Fxn fxn) Indicate that a Fxn in the group needs to be run.
static int	getMaxIterations() Get the maximum number of iterations allowed in each group, as a debugging aid.
Fxn	getRunning()
boolean	getScheduled() Ask if the Group has already been scheduled to be run
boolean	getStale() Ask if the group needs to be run.
Fxn	onSet(xdc.services.intern.xsr.Value.Observable obj, int index, org.mozilla.javascript.Callable body)
Fxn	onSet(xdc.services.intern.xsr.Value.Observable obj, java.lang.String name, org.mozilla.javascript.Callable body) Wrap the given function body as a Fxn and specify one input to fire on.
void	removeStale(Fxn fxn) Indicate that a Fxn in the group no longer needs to be run.
void	run() Run all the Fxns in the Group that need it.
void	schedule(Fxn fxn) Mark the given Fxn as stale, and schedule the whole group to be run at the next opportunity.
static void	setMaxIterations(int maxIterations) Get the maximum number of iterations allowed in each group, as a debugging aid.
void	setScheduled(boolean scheduled) Indicate that the Group has now been scheduled to be run

Methods inherited from class java.lang.Object

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

Constructor Detail

Group

public Group()

Create a new Group governed by the given scheduler

Method Detail

onSet

public Fxn onSet(xdc.services.intern.xsr.Value.Observable obj,
                 java.lang.String name,
                 org.mozilla.javascript.Callable body)

Wrap the given function body as a Fxn and specify one input to fire on. Add it to the group and execute it once.

Returns:

the Fxn, so that additional inputs and outputs can be specified.

onSet

public Fxn onSet(xdc.services.intern.xsr.Value.Observable obj,
                 int index,
                 org.mozilla.javascript.Callable body)

addAuto

public AutoFxn addAuto(org.mozilla.javascript.Callable body)

Wrap the given function body as an AutoFxn and add it to the group. Executes the function once.

A typical use is to establish two-way update between related XDCscript fields, say x.a and y.b :

   group.addAuto(function bToA(){ x.a = y.b; });
   group.addAuto(function aToB(){ y.b = x.a; });
 

This example constrains x.a and y.b to have the same value. Whenever one of them changes, one AutoFxn in the Group runs and copies the change to the other field. The Group is responsible for deciding when to execute each AutoFxn, based on examining its inputs and outputs.

Returns:

the AutoFxn, so that additional inputs and outputs can be specified.

add

public Fxn add(Fxn fxn)

Add a new Fxn to the group, and execute it once.

getStale

public boolean getStale()

Ask if the group needs to be run. Should be run whenever any Fxn in the group is stale.

addStale

public void addStale(Fxn fxn)

Indicate that a Fxn in the group needs to be run.

removeStale

public void removeStale(Fxn fxn)

Indicate that a Fxn in the group no longer needs to be run.

setScheduled

public void setScheduled(boolean scheduled)

Indicate that the Group has now been scheduled to be run

getScheduled

public boolean getScheduled()

Ask if the Group has already been scheduled to be run

getRunning

public Fxn getRunning()

run

public void run()

Run all the Fxns in the Group that need it.

schedule

public void schedule(Fxn fxn)

Mark the given Fxn as stale, and schedule the whole group to be run at the next opportunity.

getMaxIterations

public static int getMaxIterations()

Get the maximum number of iterations allowed in each group, as a debugging aid.

setMaxIterations

public static void setMaxIterations(int maxIterations)

Get the maximum number of iterations allowed in each group, as a debugging aid.