Yep, I believe that in Java, with a simple class hierarchy, you can
achieve the same end results if you have a chain of nullary
constructors, set everything right and call an initializer method
In addtion, one could have two arg constructor that did this for you.
The difference is one of design and style. We decided to go
with two arg constructors for Actors. The details of the decision
don't come to mind right now. I poked around in the logs and nothing
jumped out.
One issue is that calling
p = new PoissonClock()
p.setName(name)
p.setContainer(container)
p.PoissonClockCreater(name);
Is much more likely to cause errors than
p = new PoissonClock(name, container)
Typically someone will leave off the call to PoissonClockCreator()
and then be confused.
_Christopher
--------
Christopher,
Thanks for quick reply !
So,
What is the difference of doing between setContainer &
setName and calling constructor with container and
name arguments?
Is it setting internal Actor information missing in
first way? For example, in the following PoissonClock
actor code, I will miss the internal state setting,
(meanTime,values, output class members).
If I would put this constructor into another method
with only name parameter, say PoissonClockCreate,
without "super (container,name)" line
then call it like this, still can't I achieve same
effect?:
p = new PoissonClock()
p.setName(name)
p.setContainer(container)
p.PoissonClockCreater(name);
public void PoissonClockCreate(String name)
throws NameDuplicationException,
IllegalActionException {
//Skip this
//super (container,name);
//The rest will be same as original constructor
....
}
public PoissonClock(CompositeEntity container, String
name)
throws NameDuplicationException,
IllegalActionException {
super(container, name);
meanTime = new Parameter(this, "meanTime");
meanTime.setExpression("1.0");
meanTime.setTypeEquals(BaseType.DOUBLE);
// Set the values parameter
values = new Parameter(this, "values");
values.setExpression("{1, 0}");
values.setTypeEquals(new
ArrayType(BaseType.UNKNOWN));
// set type constraint
ArrayType valuesArrayType = (ArrayType)
values.getType();
InequalityTerm elementTerm =
valuesArrayType.getElementTypeTerm();
output.setTypeAtLeast(elementTerm);
// Call this so that we don't have to copy its
code here...
attributeChanged(values);
fireAtStart = new Parameter(this,
"fireAtStart");
fireAtStart.setExpression("true");
fireAtStart.setTypeEquals(BaseType.BOOLEAN);
}
--- Christopher Brooks <[EMAIL PROTECTED]> wrote:
> Constructing the CompositeActor/Actor/Director and
> then
> setting the name and container are not semantically
> the same if
> the constructor uses the name and container. One
> can get
> around this by being crafty, but that's not what
> what we did.
>
> I think there is pretty good argument to be made for
> doing very little
> in the constructor. We've had problems several
> times because we
> were doing too much in the constructor
>
> BTW There is some Ptolemy Corba code in the devel
> tree at
> ptII/ptolemy/actor/corba/
> This code has never been released in a formal
> Ptolemy release.
>
> See http://chess.eecs.berkeley.edu/ptexternal
> for how to access the devel tree via CVS
>
> _Christopher
> --------
>
> Hi:
>
> I am working on a Distributed Ptolemy through
> CORBA/EJB/Web Services,
>
> I am learning the Ptolemy code. I like its
> software
> architecture, that is good to me.
>
> I have a question. When we run a model with
> PtExecuteApplication provided with XML source of
> model, Ptolemy internally calls the constructor
> like
> this:
>
> public CompositeActor/Actor/Director
> (CompositeEntity
> container, String name)
>
> Here I have a question. If I would instantiate
> the
> constructor with empty argument like this:
>
> public CompositeActor()
>
> and call setContainer and setName on the result
> object:
>
> I mean:
>
> Current way:
>
> p = new Actor/CompositeActor/Director
> (container,
> name)
>
> Instead of this, this will be equal to above
> semantically:
>
> p = new Actor/CompositeActor/Director ();
> p.setContainer (container)
> p.setName(name)
>
> Thanks
>
> Best Regards
>
> Erol Akarsu
>
> public CompositeActor(Workspace workspace)
>
>
>
> public CompositeActor (CompositeEntity
> container,
> String name)
>
>
>
>
>
> __________________________________
> Yahoo! Mail - PC Magazine Editors' Choice 2005
> http://mail.yahoo.com
>
>
>
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