On Mar 24, 10:42 pm, [EMAIL PROTECTED] wrote:
> When I try to overwrite the get function of a class, amazing thing
> happens.
>
> public class Counter extends ScriptableObject{
> public Counter(){
> System.out.println(this);}
>
> ...........
> private String id;
>
> public void setId(String id){
> this.id = id;
>
> }
>
> public void jsSet_id(String id){
> this.id = id;}
>
> public String jsGet_id(){
> return this.id;}
>
> public Object get(String name, Scriptable start){
> System.out.println("Counter get "+name);
> Object obj = super.get(name, start);
> if(obj!=Scriptable.NOT_FOUND)
> return super.get(name, start);
> System.out.println("this "+this);
> System.out.println("start "+start);
>
> }
>
> .............
>
> }
>
> The test code like this:
> Object[] arg = { new Integer(7) };
> Scriptable myCounter = cx.newObject(scope, "Counter",arg);
> scope.put("c", scope, myCounter);
> Counter counter = (Counter)myCounter;
> counter.jsSet_id("id1");
> The js code is very simple ,just like this:
> c.id;
> After running it, I get the following results:
>
> " [EMAIL PROTECTED]
> [EMAIL PROTECTED]
> Counter get id
> this [EMAIL PROTECTED]
> start [EMAIL PROTECTED]
>
> Counter get id "!
>
> Now I want to know why the "
> Counter get id " appears twice? I think It only appear once!
>
> When I write the js code as this
> c.id1
> The result is like this
>
> " [EMAIL PROTECTED]
> [EMAIL PROTECTED]
>
> Counter get id1
> this [EMAIL PROTECTED]
> start [EMAIL PROTECTED]
>
> Counter get id1
> this [EMAIL PROTECTED]
> start [EMAIL PROTECTED]
> "
> Why there exist two objects, [EMAIL PROTECTED] object just keep
> the class level attribute? Can you explain this simply for me?
> Thank you!
It's not clear from your post how "Counter" is defined. I'm assuming
that you're using ScriptableObject.defineClass or something similar.
These methods that define your class will create Counter.prototype,
which is likely the "other" object that you see in your debug output.
Lookup in JavaScript walks the prototype chain, so likely the
mysterious "Counter get id" is a result of get() being called on the
"c" object, and this its prototype.
Incidentially, for most purposes it's easiest just to define the
JavaScript objects you want as normal Java objects and then expose
them to JavaScript using Context.javaToJS. The only feature you can't
get from this route is dynamic properties.
--N
_______________________________________________
dev-tech-js-engine-rhino mailing list
[email protected]
https://lists.mozilla.org/listinfo/dev-tech-js-engine-rhino
