1 /*
2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 #include <jni.h>
25
fib(jint num)26 static jlong fib(jint num) {
27 if (num == 0) {
28 return 0;
29 }
30 if (num <= 2) {
31 return 1;
32 }
33 return fib(num - 2) + fib(num -1);
34 }
35
callCallback(JNIEnv * env,jclass cls,jobject target,jlong result)36 static void callCallback(JNIEnv *env, jclass cls, jobject target, jlong result) {
37 jmethodID mid = (*env)->GetMethodID(env, cls, "callback", "(J)V");
38 if (mid == NULL) {
39 jclass nsme = (jclass) (*env)->NewGlobalRef(env, (*env)->FindClass(env, "java/lang/NoSuchMethodException"));
40 if (nsme != NULL) {
41 (*env)->ThrowNew(env, nsme, "Can't find method callback()");
42 }
43 return;
44 }
45 (*env)->CallVoidMethod(env, target, mid, result);
46 }
47
calculateAndCallCallback(JNIEnv * env,jclass cls,jobject target,jint num)48 static void calculateAndCallCallback(JNIEnv *env, jclass cls, jobject target, jint num) {
49 jlong result = -1;
50 result = fib(num);
51 callCallback(env, cls, target, result);
52 }
53
54 JNIEXPORT void JNICALL
Java_LingeredAppWithNativeMethod_callJNI(JNIEnv * env,jclass cls,jobject target,jint num)55 Java_LingeredAppWithNativeMethod_callJNI(JNIEnv *env, jclass cls, jobject target, jint num) {
56 calculateAndCallCallback(env, cls, target, num);
57 }
58