SNI - Simple Native Interface

SNI is a standardized library API registered to the ESR Consortium (ESR012).
It allows to interface Java and C code by providing calls and data sharing. SNI focuses on both simplicity and performance / memory footprints (zero-copy buffers).

Java to C call Example

Java code:

package examples;
public class Hello{

   public static void main(String[] args){
      int i = printHelloNbTimes(3);
   }
   public static native int printHelloNbTimes(int times);
}
	

C code:

#include "sni.h"
#include "stdio.h"

jint Java_examples_Hello_printHelloNbTimes(jint times){
    while (--times){
        printf(“Hello world!\n”) ;
    }
    return 0 ;
}
	

C to Java call Example

Java code:

package examples;
public class Hello{

   public static void printHelloNbTimes(int times){
      while (--times){
        System.out.println(“Hello world!”) ;
    }
   }
}
	

C code:

#include "sni.h"

void main(){
    SNI_callJavaVoidMethod(Java_examples_Hello_printHelloNbTimes, 3) ;
}
	

SP - Shilded Plug

The Shielded Plug, SP, provides a secured means to interface Java and C. While SNI allows to call directly C functions from Java, SP reduce the interfae to data messaging based on a publish / subscribe interface type.

SP provides segregation of the processes, which can be written either in C or in Java. It allows the certification of each individual part individually. The data sharing between processes uses the concept of shared memory blocks, with introspection on those blocks. Facilities provided include: notification when the content changes, re-initialization of the block, testing the presence of data in the data block, and a mechanism for serialization and de-serialization.

SP allows the creation of several data stores. These can be defined entirely statically, or increase in number during the execution of a program. Reading and writing in the shared memory are operations with predictable performance characteristics.