Traditional method for java calling c++ usually uses jni interface. This is little more difficult because programmer have to deal with calling conversion, structed memory conversion, string format conversion, record callback java handle, etc. Using cle developed by srplab, the procedure is simplified. Here is a simple example.

A function “Add” is defined in c++ which returns the sum of two input integers, the function also call java method “Show” to print the result.

Using cle to developed java extension, c++ externsion should be compiled into a sharelib which exports two functions StarCoreService_Init and StarCoreService_Term. There are four steps:

1.       Create service.

2.       Create interface object, and defines a new function “Add” of it.

3.       Write function code of Add.

4.       Set function address of Add to object’ function definition.

#include "vsopenapi.h"

static class ClassOfSRPInterface *SRPInterface;

//--Step 3 :  Add function body

static VS_INT32 Add(void *Object,VS_INT32 x,VS_INT32 y)

{

     //--Callback script function

     SRPInterface -> ScriptCall(Object,NULL,"Show","(i)",x+y);

         return x + y;

}

VS_BOOL StarCoreService_Init(class ClassOfStarCore *starcore)

{

         void *AtomicClass,*Add_AtomicFunction;

         class ClassOfBasicSRPInterface *BasicSRPInterface;

         //--Step 1 :  Create service

         BasicSRPInterface = starcore ->GetBasicInterface();         

         BasicSRPInterface ->CreateService("","AddFunctionService",NULL,"123",0,0,0,0,0,0);

         //--Step 2 :  Create object and defines a new function “Add”

         SRPInterface = BasicSRPInterface ->GetSRPInterface("AddFunctionService","root","123");

         AtomicClass = SRPInterface ->CreateAtomicObjectSimple("TestItem","TestClass",NULL,NULL,NULL);

         Add_AtomicFunction = SRPInterface ->CreateAtomicFunctionSimple(AtomicClass,"Add","VS_INT32 Add(VS_INT32 x,VS_INT32 y);",NULL,NULL,VS_FALSE,VS_FALSE);

         //--Step 4 :  Set function address to Add function

         SRPInterface -> SetAtomicFunction(Add_AtomicFunction,(void *)Add);

         return VS_TRUE;

}

void StarCoreService_Term(class ClassOfStarCore *starcore)

{

         SRPInterface -> Release();

         return;

}

Compile into sharelibrary, may be named “AddFunctionService.dll”.

For java code calls the above sharelib, there are four steps;

1.       Init cle, create service group,import sharelibrary,  and create service.

2.       Define extends class of StarObjectClass, which implement callback function “Show”.

3.       Create Instance of object “TestClass” defined in sharelibrary.

4.       call function “Add”.

import com.srplab.www.starcore.*;

//--Step2 : Define extends class of StarObjectClass and implements callback function “Show”.

class MyObjectClass extends StarObjectClass{

   public void Show( StarObjectClass self,int para )

   {

     System.out.println("print from java call back "+para);

     return;

   }

         public MyObjectClass(StarObjectClass srcobj){

                   super(srcobj);

         }     

}

public class java_call{

         public static void main(String[] args){

         //--Step1 : Init cle, create service group,import sharelibrary,  and create service

                   StarCoreFactory starcore= StarCoreFactory.GetFactory();

                   StarServiceClass Service=starcore._InitSimple("test","123",0,0,"AddFunctionService.dll");

                   //--Step3 : Create Instance of object “TestClass” defined in sharelibrary.

                   MyObjectClass a = new MyObjectClass( Service._GetObject("TestClass")._New() );

                   //--Step4 : call function “Add”.

        System.out.println("Add returns : "+a._Call("Add",12,34));

        starcore._ModuleExit();

    }

}