JavaCPP export Library clone as C++ class files about javacpp

[eix128]

For example with the help of JavaCPP.
https://github.com/hoary/JavaAV
I can use this library from C++ directly.

[saudet]

It wasn't designed for that, no... Check the README.md file for some options.

[eix128]

I know but its not that hard to do with ANTLR Library

[saudet]

I'm not sure why ANTLR would help with that. We don't really need to parse anything... Am I missing something?

[eix128]

so how can you convert Java code to C++ ?? I can help you about library.
I have some source codes for you

[eix128]

You can call JavaVM inside C++ with the help of JNI Library on C++

[eix128]

You can invoke with that code:

JavaVM *InitJVM(JNIEnv **env2) {
    JavaVM* vm;
    JNIEnv* env;
    JavaVMInitArgs vm_args;
    JavaVMOption options[3];

    CHAR lpDataTempClass[MAX_PATH];
    CHAR lpchDataLib[MAX_PATH];

    TCHAR lpchRuntimelib[MAX_PATH];
    TCHAR lpchJavaPath[MAX_PATH];


    jobjectArray    joApplicationArgs;
    *env2 = NULL;
    /* disable JIT */
    //options[0].optionString ="-Djava.compiler=NONE";
    /* user classes */
    //"-Djava.class.path=c:\\myclasses"


    //Pointer to the function JNI_CreateJavaVM
    HKEY key;
    BOOL foundDLL;
    TCHAR lpchRuntimePath[MAX_PATH];
    TCHAR lpchJavaHome[MAX_PATH];

    TCHAR lpchThisPath[MAX_PATH];
    GetThisPath(lpchThisPath,MAX_PATH);


    HRESULT result = RegOpenKeyEx(HKEY_LOCAL_MACHINE, L"Software\\JavaSoft\\Java Runtime Environment", 0, KEY_QUERY_VALUE,&key);
    char *lpVal = readStringRegValue(key, "CurrentVersion");

    if ( lpVal != NULL ) {
        TCHAR lpchJVMRuntime[MAX_PATH];

        HKEY subkey;
        result = RegOpenKeyExA(key, lpVal, 0, KEY_QUERY_VALUE, &subkey);
        if(result == ERROR_SUCCESS) {
            readStringRegValueW(subkey, _T("RuntimeLib"), lpchJVMRuntime );
            readStringRegValueW(subkey, L"JavaHome", lpchJavaHome);
            //lpchJavaHome = readStringRegValue( subkey , "JavaHome" );
            if(hinst_JVM == NULL) {
                //WCHAR achRuntimePath[MAX_PATH];
                //MultiByteToWideChar(  CP_ACP , 0 , lpchJVMRuntime , -1 , achRuntimePath , MAX_PATH );
                //CHAR *achCustomLib = "C:\\Program Files\\Java\\jre6\\bin\\client\\jvm.dll";
                hinst_JVM = LoadLibraryW( lpchJVMRuntime );
                DWORD errCode = GetLastError( );
                if (!hinst_JVM) {
                    WCHAR lpchJVMBinPath[MAX_PATH];
                    WCHAR lpchFullFilePath[MAX_PATH];
                    WCHAR lpchJavaHomeW[MAX_PATH];
                    WCHAR lpchClientPath[MAX_PATH];
                    //hinst_JVM = LoadLibraryA("jvm.dll");
                    EnumerateSubKeys(HKEY_LOCAL_MACHINE, "Software\\JavaSoft\\Java Runtime Environment", &foundDLL, lpchRuntimePath, lpchJavaHome);
                    if (foundDLL) {
                        wsprintfW(lpchJVMBinPath, L"%s\\bin", lpchJavaHome);
                        wsprintfW(lpchClientPath, L"%s\\bin\\client\\", lpchJavaHome);
                        CVector<CUIString> values;
                        listFiles(lpchJVMBinPath, values);
                        for (int j = 0; j < values.size(); j++) {
                            CUIString *str = values.getElementAt(j);
                            WCHAR *value = str->c_str();
                            if (wcsstr(value, L"msvcr") && wcsstr(value, L".dll")) {
                                //lpchFullFilePath
                                WCHAR wchCombinedPath[MAX_PATH];
                                wsprintfW(wchCombinedPath, L"%s\\%s", lpchJVMBinPath, value);
                                wcscat(lpchClientPath, value);
                                CopyFile(wchCombinedPath, lpchClientPath, FALSE);
                                wcscat(lpchThisPath, _T("\\"));
                                wcscat(lpchThisPath, value);
                                CopyFile(wchCombinedPath, lpchThisPath, FALSE);
                                break;
                            }
                        }
                    }
                    else {
                        //no jvm
                        RegCloseKey(key);
                        RegCloseKey(subkey);
                        return NULL;
                    }
                }
                //jvm.dll found
                else {
                    WCHAR lpchJVMBinPath[MAX_PATH];
                    WCHAR lpchFullFilePath[MAX_PATH];
                    WCHAR lpchJavaHomeW[MAX_PATH];
                    WCHAR  lpchClientPath[MAX_PATH];

                    wsprintfW(lpchJVMBinPath, L"%s\\bin", lpchJavaHome);
                    wsprintfW(lpchClientPath, L"%s\\bin\\client\\", lpchJavaHome);

                    CVector<CUIString> values;
                    listFiles(lpchJVMBinPath, values);
                    for (int j = 0; j < values.size(); j++) {
                        CUIString *str = values.getElementAt(j);
                        WCHAR *value = str->c_str();
                        if (wcsstr(value, L"msvcr") && wcsstr(value, L".dll")) {
                            //lpchFullFilePath
                            WCHAR wchCombinedPath[MAX_PATH];
                            wsprintfW(wchCombinedPath, L"%s\\%s", lpchJVMBinPath, value);
                            wcscat(lpchClientPath, value);
                            CopyFile(wchCombinedPath, lpchClientPath, FALSE);
                            wcscat(lpchThisPath, _T("\\"));
                            wcscat(lpchThisPath, value);
                            CopyFile(wchCombinedPath, lpchThisPath , FALSE);
                            break;
                        }
                    }
                }
            }

            RegCloseKey(subkey);
        }
    } else {
        //NO JVM Installed
    }

    RegCloseKey(key);

    if(hinst_JVM == NULL) {
        return NULL;
    }

    //java -Djava.library.path=C:\Users\Kadir\IdeaProjects\WebcamTransmitter\nativeLib\windows\x64 -cp logback-classic-1.1.3.jar;logback-core-1.1.3.jar;WebcamTransmitter-1.0-SNAPSHOT.jar;bridj-0.6.2.jar;ffmpeg-2.6.1-0.11.jar;ffmpeg-2.6.1-0.11-windows-x86_64.jar;javacpp-0.11.jar;webcam-capture-0.3.10.jar;slf4j-api-1.7.2.jar service.WebcamCapture
    //java -Djava.library.path=C:\Users\Kadir\IdeaProjects\WebcamTransmitter\nativeLib\windows\x86 -cp logback-classic-1.1.3.jar;logback-core-1.1.3.jar;WebcamTransmitter-1.0-SNAPSHOT.jar;bridj-0.6.2.jar;ffmpeg-2.6.1-0.11.jar;ffmpeg-2.6.1-0.11-windows-x86_64.jar;javacpp-0.11.jar;webcam-capture-0.3.10.jar;slf4j-api-1.7.2.jar service.WebcamCapture


    //Get the address of the function
    pfnCreateJavaVM = (CreateJavaVM_t*)GetProcAddress(hinst_JVM, "JNI_CreateJavaVM");
    pfnGetDefaultJavaVMOptions = (OptionsJavaVM_t*)GetProcAddress(hinst_JVM, "JNI_GetDefaultJavaVMInitArgs");
    //-Djava.class.path
    //"logback-classic-1.1.3.jar;logback-core-1.1.3.jar;WebcamTransmitter-1.0-SNAPSHOT.jar;bridj-0.6.2.jar;ffmpeg-2.6.1-0.11.jar;ffmpeg-2.6.1-0.11-windows-x86_64.jar;javacpp-0.11.jar;webcam-capture-0.3.10.jar;slf4j-api-1.7.2.jar"

    CHAR achTemp[MAX_PATH];
    {
        TCHAR achTemp2[MAX_PATH];
        GetTempPath(MAX_PATH, achTemp2);
        int sizeNeed = WideCharToMultiByte(CP_UTF8, 0, achTemp2, MAX_PATH, achTemp, 0, NULL, NULL);
        WideCharToMultiByte(CP_UTF8, 0, achTemp2, MAX_PATH, achTemp, sizeNeed, NULL, NULL);
        int dataLen = wcslen(achTemp2) - 1;
        if (achTemp[dataLen] == '\\') {
            achTemp[dataLen] = L'\0';
        }
    }


    //SHCreateDirectoryEx(T("C:\\Foo\\Bar\\Baz"));


    sprintf( lpDataTempClass, "-Djava.class.path=%s;%ls\\lib;", achTemp , lpchJavaHome );
    options[ 0 ].optionString = lpDataTempClass;

    CHAR lpDataTempClass2[ 2048 ];

    CHAR lpData[MAX_PATH];
    TCHAR lpData2[MAX_PATH];

    GetThisPath(lpData2, 2048);

    int sizeNeed = WideCharToMultiByte(CP_UTF8, 0, lpData2, MAX_PATH, lpData , 0 , NULL , NULL );
    WideCharToMultiByte(CP_UTF8, 0, lpData2, MAX_PATH, lpData , sizeNeed, NULL, NULL);

#ifdef _WIN64
    sprintf(lpDataTempClass2, "%s\\libn\\x64", lpData);
    CreateDirectoryRecA( lpDataTempClass2 );
    sprintf(lpDataTempClass2, "-Djava.library.path=%s\\bin;%s\\libn\\x64", lpchJavaHome, lpData );
#else
    sprintf(lpDataTempClass2, "%s\\libn\\x86", lpData);
    CreateDirectoryRecA(lpDataTempClass2);
    sprintf(lpDataTempClass2, "-Djava.library.path=%s\\bin;%s\\libn\\x86", lpchJavaHome, lpData );
#endif

    options[1].optionString = lpDataTempClass2;
    //options[0].optionString = "-Djava.complier=JIT"; 
    /* native lib path */
    //"-Djava.library.path=c:\\mylibs"
    //sprintf(lpchDataLib,"-Djava.library.path=%s",lpchLibrary);
    options[2].optionString = "-Djava.complier=JIT"; 

    pfnGetDefaultJavaVMOptions(&vm_args); 
    vm_args.version = JNI_VERSION_1_6;//JNI_VERSION_1_4; 
    vm_args.options = options;
    vm_args.nOptions = 3;
    vm_args.ignoreUnrecognized = TRUE;

    if(pfnCreateJavaVM == NULL) {
        return NULL;
    }

    if(!pfnGetDefaultJavaVMOptions) {
        FreeLibrary(hinst_JVM);
        return NULL;
    }

    //Create JVM
    jint iRetval = pfnCreateJavaVM(&vm, (void**)&env,&vm_args);

    //Error handling.
    if (iRetval < 0) {
        vm_args.nOptions = 2;
        options[2].optionString = NULL;
        iRetval = pfnCreateJavaVM(&vm, (void**)&env,&vm_args);
        if(iRetval < 0) {
            return NULL;
        }
    }
    *env2 = env;
    return vm;
}

[eix128]

That works for Win32.
Also it can work on Linux and MAC too with some little work

[eix128]

JavaCPP will make C++ code from Java class library.
Invoke Java from C++.
and wrap the class file with C++ methods

[eix128]

jar files will be used a dll inside C++ can be good idea!

[eix128]

I will give you example C++ code for that if you want to add such capability to JavaCPP

[saudet]

As mentioned in the README.md file, there's already solutions like Jace and JunC++ion for that. What is missing from those two?

[saudet]

There's also jni.hpp these days: https://github.com/mapbox/jni.hpp