Casting jobjects

Question

Hi,
i face a problem in casting jobject in JNI. From Java layer i receive a DataType of super class object. but in JNI layer i need to access the methods of subclass, for that i need to cast to subclass.
I tried to cast the jobject to my DataType. This class only have virtual Methods, so i cannot call those Methods. Then I tried to cast it to an implementation of DataType Class (my Subclasses). If I try to access the Methods of the Subclass I get a segFault.
Help!?
Thanks in advance

Answer 1

Okay you're right, my explanation was not exactly that what i mean. I try it again.
1. I have a cpp Framework. In this Framework there are some structure those look like:
class superclass{
virtual get/set method();
}then there is more then one subclass:
class subclass : public superclass{
//impelmentation of the methods
get/set methods
}2. Then I created a Java Wrapper using JNI. This still works. But I want to extend the Framework, with some Java Class. Therefore I want to registrate using the invocation API those Java Classes.
with the Invocation API i do:
1. Get the class id (base class)
2. Get the method id
3. Call the class.
4. the return type is an user defined Type and for every Subclass different.
3. And the Java Method i called looke like this:
public superclass get(){
superclass returnValue = new subclass();
//set some userdefined Value to the return Value
return superclass;
}I the Java Method is also everything okay.
The Problem is in part 2. I want to have the Data from the subclass which are accessable from Java, also accessable in cpp. So if I called the Java-Method which returns the superclass i get an jobject.
superclass *superCls = (superclass*)callMethod();
subclass *subCls = dynamic_cast<subclass*>(superCls);The last 2 lines ?? How can i realize that???
THanks
Edited by: port54 on Mar 1, 2008 2:52 AM