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 #include <jni.h>
24 #include <stdio.h>
25
26 extern "C" {
27
28 /* A C function that takes a reference to java Object( a circular Linked list)
29 and utilizes this reference to do a java method callback to determine the
30 number of elements in the linked list */
31 JNIEXPORT jint JNICALL
32 Java_gc_gctests_nativeGC02_nativeGC02_nativeMethod02
33 (JNIEnv *env, jobject obj, jobject linked_list) {
34 jclass cls, clss;
35 jmethodID mid, mid2;
36 jfieldID fid;
37 jobject llist;
38 int elementCount;
39
40 /* Store a reference to the linked list in the C stack */
41
42 clss = env->GetObjectClass(obj);
43 fid = env->GetFieldID(clss, "cl", "Lnsk/share/gc/CircularLinkedList;");
44 if (fid == 0) {
45 printf("could not locate field - cl\n");
46 return -1;
47 }
48
49 llist = env->GetObjectField(obj, fid);
50
51 /* force a GC by invoking a callback where System.gc() is called
52 */
53
54 cls = env->GetObjectClass(obj);
55 mid = env->GetMethodID(cls, "callbackGC", "()V");
56 if (mid == 0){
57 printf("couldnt locate method callbackGC()\n");
58 return -1;
59 }
60 env->CallVoidMethod(obj,mid);
61
62 /* Now that a GC has been done, invoke the callback
63 that counts the number of elements in the
64 circular linked list
65 */
66
67 clss = env->GetObjectClass(linked_list);
68 mid2 = env->GetMethodID(clss, "getLength", "(Lnsk/share/gc/CircularLinkedList;)I" );
69 if (mid2 == 0 ){
70 printf("couldnt locate method getLength(CircularLinkedList)\n");
71 return -1;
72 }
73 elementCount = env->CallIntMethod(linked_list, mid2, llist);
74 return elementCount;
75 }
76
77 }
|
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 #include <jni.h>
24 #include <stdio.h>
25
26 extern "C" {
27
28 /* A C function that takes a reference to java Object(a circular Linked list)
29 and utilizes this reference to do a java method callback to determine the
30 number of elements in the linked list */
31 JNIEXPORT jint JNICALL
32 Java_gc_gctests_nativeGC02_nativeGC02_nativeMethod02
33 (JNIEnv *env, jobject obj, jobject linked_list) {
34 jclass cls, clss;
35 jmethodID mid, mid2;
36 jfieldID fid;
37 jobject llist;
38 int elementCount;
39
40 /* Store a reference to the linked list in the C stack */
41
42 clss = env->GetObjectClass(obj);
43 fid = env->GetFieldID(clss, "cl", "Lnsk/share/gc/CircularLinkedList;");
44 if (fid == 0) {
45 printf("could not locate field - cl\n");
46 return -1;
47 }
48
49 llist = env->GetObjectField(obj, fid);
50
51 /* force a GC by invoking a callback where System.gc() is called
52 */
53
54 cls = env->GetObjectClass(obj);
55 mid = env->GetMethodID(cls, "callbackGC", "()V");
56 if (mid == 0) {
57 printf("couldnt locate method callbackGC()\n");
58 return -1;
59 }
60 env->CallVoidMethod(obj,mid);
61
62 /* Now that a GC has been done, invoke the callback
63 that counts the number of elements in the
64 circular linked list
65 */
66
67 clss = env->GetObjectClass(linked_list);
68 mid2 = env->GetMethodID(clss, "getLength", "(Lnsk/share/gc/CircularLinkedList;)I");
69 if (mid2 == 0) {
70 printf("couldnt locate method getLength(CircularLinkedList)\n");
71 return -1;
72 }
73 elementCount = env->CallIntMethod(linked_list, mid2, llist);
74 return elementCount;
75 }
76
77 }
|