jni jnienv NewLongArray example c c++ java

New<PrimitiveType>Array Routines - NewLongArray

ArrayType New<PrimitiveType>Array(JNIEnv *env, jsize length);

A family of operations used to construct a new primitive array object. Table 4-8 describes the specific primitive array constructors. You should replace New<PrimitiveType>Array with one of the actual primitive array constructor routine names from the following table, and replace ArrayType with the corresponding array type for that routine.(NewLongArray)

Table 4-8a New<PrimitiveType>Array Family of Array Constructors

New<PrimitiveType>Array Routines	Array Type
NewBooleanArray()	jbooleanArray
NewByteArray()	jbyteArray
NewCharArray()	jcharArray
NewShortArray()	jshortArray
NewIntArray()	jintArray
NewLongArray()	jlongArray
NewFloatArray()	jfloatArray
NewDoubleArray()	jdoubleArray

LINKAGE:

Indices in the JNIEnv interface function table.

Table 4-8b New<PrimitiveType>Array Family of Array Constructors

New<PrimitiveType>Array Routines	Index
NewBooleanArray()	175
NewByteArray()	176
NewCharArray()	177
NewShortArray()	178
NewIntArray()	179
NewLongArray()	180
NewFloatArray()	181
NewDoubleArray()	182

PARAMETERS of NewLongArray

env: the JNI interface pointer.

length: the array length.

RETURNS of NewLongArray

Returns a Java array, or NULL if the array cannot be constructed.

Example of NewLongArray

JNIEXPORT jlongArray JNICALL Java_javaxt_io_File_GetFileAttributesEx(JNIEnv *env, jclass, jstring filename)
{   

  //Convert jstring to wstring
    const jchar *_filename = env->GetStringChars(filename, 0);
    jsize len = env->GetStringLength(filename);
    wstring path;
    path.assign(_filename, _filename + len);
    env->ReleaseStringChars(filename, _filename);


  //Get attributes
    WIN32_FILE_ATTRIBUTE_DATA fileAttrs;
    BOOL result = GetFileAttributesExW(path.c_str(), GetFileExInfoStandard, &fileAttrs);
    if (!result) {
        jclass exceptionClass = env->FindClass("java/lang/Exception");
        env->ThrowNew(exceptionClass, "Exception Occurred");
    }

  //Create an array to store the WIN32_FILE_ATTRIBUTE_DATA
    jlong buffer[6];
    buffer[0] = fileAttrs.dwFileAttributes;
    buffer[1] = date2int(fileAttrs.ftCreationTime);
    buffer[2] = date2int(fileAttrs.ftLastAccessTime);
    buffer[3] = date2int(fileAttrs.ftLastWriteTime);
    buffer[4] = fileAttrs.nFileSizeHigh;
    buffer[5] = fileAttrs.nFileSizeLow;

    jlongArray jLongArray = env->NewLongArray(6);
    env->SetLongArrayRegion(jLongArray, 0, 6, buffer);
    return jLongArray;
}