Subj : Re: RHino newbie: getter not working
To   : netscape.public.mozilla.jseng
From : Brian J. Sayatovic
Date : Tue Jan 18 2005 08:02 pm

Igor Bukanov wrote:

> Brian J. Sayatovic wrote:
>
>> I wrote a simple Java class hierarchy...
>>
>>    ScriptableObject-->MyObject-->MyNode-->MyView-->MyCanvas
>>
>> The final class has this in it:
>>
>>    public String jsGet_build() {
>>        return "2";
>>    }
>>
>> I then have a script that looks like this:
>>
>>    var canvas = new Packages.org.trinition.mytest.MyCanvas();
>>    canvas; // or canvas.build;
>>
>> When I execute this script, I use the following:
>>
>>            String filename2 = "Test Data/test1.js";
>>            FileReader reader = new FileReader(filename2);
>>                      Object result = context.evaluateReader(scope, 
>> reader, filename2, 1, null);
>>                      System.out.println("Result: " + result);
>>
>> The return value for "canvas;" is:
>>
>>    Result: org.trinition.mytest.MyCanvas@13ad085
>>
>> However, when I use "canvas.build;", I get:
>>
>>    Result: org.mozilla.javascript.Undefined@18e2b22
>>
>> I don't understand why my getter isn't working.  What am I doing wrong?
>
>
> To make getters in classes extending from ScriptableObject to work you 
> have to call ScriptableObject.defineClass(scope, yourClass). It will 
> prepare your class instances to behave as standard ECMAScript objects. 
> For example, assuming that MyCanvas contains:
>
> public String getClassName() { return "MyCanvas"; }
>
> after ScriptableObject.defineClass(scope, MyCanvas.class) the scope 
> would contain MyCanvas constructor that you can use to create 
> instances of MyCanvas. As with the standard objects like Date or Array 
> you will get MyCanvas.prototype which scripts can populate with 
> additional functions like with any other Constructor.prototype cases. 
> MyCanvas.prototype also contains objects wrapping getters and setters 
> and that is why without calling defineClass they do not work.
>
> Regards, Igor
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> mozilla-jseng mailing list
> mozilla-jseng@mozilla.org
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>
Actually, after all of my care to make sure I typed all of the details 
in, I neglected to mention that I'm already doing a defineClass for my 
class (although my getClassName() returns the fully quilified class 
name, org.trinition.mytest.MyCanvas).  In fact, I think that's why the 
toString() of the result for "canvas;" was 
org.trinition.mytest.MyCanvas@13ad085 instead of undefined.  It seems it 
is only the properties of MyCanvas that result in undefined being returned.

I also tried a "for(var prop in canvas) { ...", but the loop terminates 
with no iterations meaning 'canvas' has no properties.

I'm really baffled.  I feel like I followed the documentaiton precisely, 
yet it doesn't work.

Regards,
Brian.

.