C++ and JAIDA

To access the Java implementation of the AIDA interfaces from C++ you need to download the AIDAJNI glue code that will allow you to operate on the JAIDA objects from C++.

To change the type of analysis factory to be used (with/without GUI) as for the Java case by specifying it via the JVM_ARGS environment variable that is read when the Java Virtual Machine is started. So, for an analysis factory with the GUI

set JVM_ARGS=-Dhep.aida.IAnalysisFactory=hep.aida.ref.AnalysisFactory

Code

The following code illustrates how to invoke the AIDA interfaces from C++.

#include <iostream>
#include <cstdlib>

#include "AIDA/AIDA.h"
#include "JIAnalysisFactory.h"

using namespace AIDA;

int main(int argc, char *argv[]) {

        AIDA::IAnalysisFactory* factory = AIDA_createAnalysisFactory();
        ITree*              tree    = factory->createTreeFactory()->create("UsingJAIDAFromCPP.aida","xml",false,true);
        IHistogramFactory*  hf      = factory->createHistogramFactory(*tree);

        tree->mkdir("/Histograms");
        tree->cd("/Histograms");

        IHistogram1D* h1 = hf->createHistogram1D("Histogram 1D",50,0,10);
        IHistogram2D* h2 = hf->createHistogram2D("Histogram 2D",40,0,10,40,0,10);
        
        tree->mkdir("/Clouds");
        tree->cd("/Clouds");
        
        ICloud1D* c1 = hf->createCloud1D("Cloud 1D");
        ICloud2D* c2 = hf->createCloud2D("Cloud 2D");

        IPlotter* page1 = factory->createPlotterFactory()->create("Page1");

        page1->show();
        page1->createRegions(2,2);

        page1->region(0)->plot(*h1);
        page1->region(1)->plot(*h2);
        page1->region(2)->plot(*c1);
        page1->region(3)->plot(*c2);

        srand( 0 );
        for ( int i = 0; i < 10000; i++ ) {
            h1->fill( 10*rand()/(double)RAND_MAX );
            h2->fill( 10*rand()/(double)RAND_MAX, 10*rand()/(double)RAND_MAX);
            c1->fill( 10*rand()/(double)RAND_MAX );
            c2->fill( 10*rand()/(double)RAND_MAX, 10*rand()/(double)RAND_MAX);
        }
        tree->commit();
        delete factory;
        return 1;
}

Please notice that in the above code, before the return statement, the JIAnalysisFactory is deleted. This way the execution thread will wait on the GUI to stop running.

Execution

To run the above example tt is necessary to compile and link the code against the AIDAJNI libraries required for your platform.

  • set the environment variable AIDAJNI_HOME to point the directory where the AIDAJNI code has been put
  • set the environment variable JDK_HOME to point the the head of the Java distribution (a least 1.4.0 is required)

Windows

  • compile with:
    cl -c -TP -Og -W1 -nologo -MD -G5 -GX -GR -Zm200 -DWINVER=0x0400 -DWIN32 -D_WIN32 -I%AIDAJNI_HOME%\include 
    -I%JDK_HOME%\include -I%JDK_HOME%\include\win32 UsingJAIDAFromCPP.cpp
  • link with 
    link -nologo -LIBPATH:%AIDAJNI_HOME%\lib\WIN32-VC UsingJAIDAFromCPP.obj AIDAJNI.lib %JDK_HOME%/lib/jvm.lib FHJNI.lib

Before executing make sure that you add to your PATH the directory of the Java Virtual Machine sharable library

set PATH=%PATH%;%JDK_HOME%\jre\bin\client