Groups > comp.lang.java.programmer > #7710

Trouble with JNI wrapper functions

From	"Colby Nyce" <cnyce@mathworks.com>
Newsgroups	comp.lang.java.programmer
Subject	Trouble with JNI wrapper functions
Date	2011-09-08 15:10 -0400
Organization	MathWorks
Message-ID	<j4b3uf$efj$1@newscl01ah.mathworks.com> (permalink)

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Hi all,

I am trying to call Java methods from C++ code using the JNI wrapper 
functions that we have available in the "jmi" library, but I am having 
difficulty figuring out how to obtain one of the required input variables. 
I need to use any one of the "mljCall<type>Method" functions, such as:

mljCallVoidMethod
mljCallIntMethod
mljCallBooleanMethod
etc

These functions accept at least two parameters.  The first is a "jobject", 
and the second is a "jmethodID" (any additional arguments are treated as 
input parameters to your Java method).  I have been able to get an address 
to my Java method, but I am not sure how to get an appropriate "jobject" to 
use with this function.  The code I have boils down to this:

/**************************************************************************/
    jclass objectClass = mljFindClass("WebScopeInterfaceToJava");
    jmethodID webscopeMethod = mljGetMethod(objectClass, "voidMethod", 
"()V");
    jobject j_obj = // How do I get this?
    mljCallVoidMethod(j_obj,webscopeMethod);
/**************************************************************************/


Where do I get the correct "jobject" from?  Is this available from the 
global JVM or something?  I have looked through a lot of the source code, 
but I am finding it to be somewhat cryptic.  Please bear with me, I am 
completely new to JNI!

Thanks,
Colby
x7888

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Trouble with JNI wrapper functions "Colby Nyce" <cnyce@mathworks.com> - 2011-09-08 15:10 -0400
  Re: Trouble with JNI wrapper functions Roedy Green <see_website@mindprod.com.invalid> - 2011-09-08 12:35 -0700

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