Solved

sending and retriveing struct using JNI

Posted on 1997-10-08
2
312 Views
Last Modified: 2012-05-04
My native code is written in C++ that contains many methods
that has struct as arguments and return types.
I read up the sun's java page on JNI and I am able to call
my native methods and pass strings and primitive types.
I would like to be able to send Java objects to my native methods and which in turn should be converted to struct and
passed to native methods.
Is there a way that I can use JNI to convert my java objects
to structures and pass it to my native methods and also
take the return structures from my native methods and convert them back to java object ?

any help would be greatly appreciated

thanks
0
Comment
Question by:praveen090397
  • 2
2 Comments
 
LVL 6

Expert Comment

by:jpk041897
ID: 1228178
The problem you are running into is that structs and classes are implemented internaly as pointers to memory areas, rather than primitive data types.

As it stands, your best bet would be to implement iterators over your classes/structs using RTTI type functions to obtain the primitive objects that make up your struct and transfer those.

You can then write methods in both C++ an Java that can rebuild the struct/classses on the recieving end.

Let me know if this approach is acceptable and I'll try to post more detailed info as an answer.
0
 
LVL 6

Accepted Solution

by:
jpk041897 earned 90 total points
ID: 1228179
If the approach I mentioned erlier is not acceptable, then here are other alternatives:

1. Wrap your Java Structures inside a new class, any class, and implement methods to transfer your struct variables to and from this class.

Once the class has been updated with the data you require, you can then use JNI to transfer the object itself. This would cause JNI to tranfer the address of the Object, which you could then access in C++ in order to extract the information.

2.- A probably less complicated workarroun for achieving the same result would be to use a CORBA client and server, running on the same box using localhost addressing, to transfer your structs. CORBA's IDL implementation supports both struct and any data types so you could use this approach as a somwhat simple alternative.
0

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
How to convert String matching to regex in java 4 51
jdbc error in jsp application 20 63
maven module vs maven project 3 47
Problem to Alipay 10 44
INTRODUCTION Working with files is a moderately common task in Java.  For most projects hard coding the file names, using parameters in configuration files, or using command-line arguments is sufficient.   However, when your application has vi…
Introduction This article is the second of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article covers the basic installation and configuration of the test automation tools used by…
This tutorial will introduce the viewer to VisualVM for the Java platform application. This video explains an example program and covers the Overview, Monitor, and Heap Dump tabs.
This tutorial explains how to use the VisualVM tool for the Java platform application. This video goes into detail on the Threads, Sampler, and Profiler tabs.

831 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question