transfer of a java object with JNI

[nora1966]

Hi;

I search an JNI example with C/C++ to check if it is possible to send a java object with JNI.
I have a class java “A” with 2 methods:
- getCustomer (): get an java object Customer
- checkCustomer (Customer c): print an Customer object
The external prog (C/++ or other) calls the method “getPeronne” to retrieve an Customer object empties, it fills and it must return to java prog via the method checkCustomer or another means to be store in database.
For the “getPersonne” method it is OK for my but I would like to know how implement the return of object “Customer” ?

Regards;

 

[Diancecht]

What do you mean with "send"? Pass as parameter or actually send it through a socket or something?

Cheers,
Dian

 

[sedj]

See this article, it describes the use of returning custom Java objects.

http://www.javaworld.com/javaworld/javatips/jw-javatip54.html

Particularly :

JNIEXPORT jobject JNICALL Java_SysInfo_getVersion (JNIEnv *env, jclass clazz)
{
    OSVERSIONINFO osVersionInfo;
    // Get operating system version information.
    osVersionInfo.dwOSVersionInfoSize = sizeof (OSVERSIONINFO);
    GetVersionEx (&osVersionInfo);
    // Attempt to find the Version class.
    clazz = env->FindClass ("Version");
    // If this class does not exist then return null.
    if (clazz == 0)
            return 0;
    // Allocate memory for a new Version class object.  Do not bother calling
    // the constructor (the default constructor does nothing).
    jobject obj = env->AllocObject (clazz);
    // Attempt to find the major field.
    jfieldID fid = env->GetFieldID (clazz, "major", "I");
    // If this field does not exist then return null.
    if (fid == 0)
            return 0;
    // Set the major field to the operating system's major version.
    env->SetIntField (obj, fid, osVersionInfo.dwMajorVersion);
    // Attempt to find the minor field.
    fid = env->GetFieldID (clazz, "minor", "I");
    // If this field does not exist then return null.
    if (fid == 0)
            return 0;
    // Set the minor field to the operating system's minor version.
    env->SetIntField (obj, fid, osVersionInfo.dwMinorVersion);
    return obj;
}

where the "Version" class is :

public class Version
{
   int major;
   int minor;
}

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