Dynamic class creation

[wesselch]

Hello,

I have following code:

I quer {
S class="de.hhla.frucht.email.gui.anhangquer.cls"
S ref=##class("de.hhla.frucht.email.gui.anhangquer").%New()
}
ELSE {
S class="de.hhla.frucht.email.gui.anhang.cls"
S ref=##class("de.hhla.frucht.email.gui.anhang").%New()
}

Is there any chance to use the scalar 'class' as parameter for the
class constructor, e.g.
S ref=##class(class).%New() ; that doesn't work

christian

[Michael Braam]

You could use the $zobjclassmethod function:

...
Set ref = $zobjclassmethod(class,"%New")
...

should work.

See the docs for more information.

Hope this helps.

Michael Braam
Senior Sales Engineer

InterSystems GmbH
Hilpertstr. 20a
D-64295 Darmstadt
Tel.: +49 (0)6151 / 1747-0
Fax: +49 (0)6151 / 1747-11
Michae...@InterSystems.com
www.InterSystems.de
Geschäftsführer: Jörg Klingler, John Macheras, Stephen G. Baron
Eingetragen beim AG Darmstadt unter HRB 4966

-----Ursprüngliche Nachricht-----
Von: intersys...@googlegroups.com
[mailto:intersys...@googlegroups.com] Im Auftrag von wesselch
Gesendet: Dienstag, 16. Februar 2010 08:59
An: InterSystems: Zen Community
Betreff: [InterSystems-Zen] Dynamic class creation

Hello,

I have following code:

christian

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[Michael Braam]

Or in a more object style:

Set ref = $system.OBJ.New(class)

regards

Michael Braam
Senior Sales Engineer

InterSystems GmbH
Hilpertstr. 20a
D-64295 Darmstadt
Tel.: +49 (0)6151 / 1747-0
Fax: +49 (0)6151 / 1747-11
Michae...@InterSystems.com
www.InterSystems.de
Geschäftsführer: Jörg Klingler, John Macheras, Stephen G. Baron
Eingetragen beim AG Darmstadt unter HRB 4966

-----Ursprüngliche Nachricht-----
Von: intersys...@googlegroups.com
[mailto:intersys...@googlegroups.com] Im Auftrag von wesselch
Gesendet: Dienstag, 16. Februar 2010 08:59
An: InterSystems: Zen Community
Betreff: [InterSystems-Zen] Dynamic class creation

Hello,

I have following code:

christian

--

[Daniel Gregory]

Hello Christian,

 

There are some utilities that will help you achieve whgat you are trying to do.  There is a method in $System.OBJ called "New".   Here is the syntax:

Set obj = $System.OBJ.New("Person")

 

You can also use the $ZOBJCLASSMETHOD utility.  This allows you to pass parameters into the constructor...here is an example class that I will create an  instance of using the utility...the constructor has two parameters...

///Example for Christian
Class spirit.test.cls.Sample Extends %RegisteredObject
{

Property First As %String;

Property Last As %String;

/// This callback method is invoked by the <METHOD>%New</METHOD> method to
/// provide notification that a new instance of an object is being created.
///
/// <P>If this method returns an error then the object will not be created.
/// <p>It is passed the arguments provided in the %New call.
/// When customizing this method, override the arguments with whatever variables and types you expect to receive from %New().
/// For example, if you're going to call %New, passing 2 arguments, %OnNew's signature could be:
/// <p>Method %OnNew(dob as %Date = "", name as %Name = "") as %Status
Method %OnNew(first as %String,last as %String) As %Status [ Private, ProcedureBlock = 1, ServerOnly = 1 ]
{
set ..First=first
set ..Last=last
Quit $$$OK
}

}

Here is how I would use the utility to create an instance...

 

USER>s cls="spirit.test.cls.Sample"
 
USER>s method="%New"
 
USER>s p1="Danny"
 
USER>s p2="Gregory"
  
USER>s object=$ZOBJCLASSMETHOD(cls,method,p1,p2)
 

USER>w object.First
Danny

 

USER>w object.Last
Gregory

There are two methods for creating objects.  Please also take a peek at the $ZOBJMETHOD utility...it allows you to dynamically call an instance method...versus the $ZOBJCLASSMETHOD, which allows you to call static methods on a class.  Also take a peek at $ZOBJPROPERTY.

 

I hope that helps.

 

Sincerely,

Danny

 

---

From: wesselch <wes...@hhla.de>
To: InterSystems: Zen Community <intersys...@googlegroups.com>
Sent: Tue, February 16, 2010 2:58:46 AM
Subject: [InterSystems-Zen] Dynamic class creation