63 lines
2.4 KiB
C
63 lines
2.4 KiB
C
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/*
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* Copyright (c) 2005, 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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#include <jni.h>
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#include <stdio.h>
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/*
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* A C function that takes a reference to java Object( a circular Linked list)
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* and utilizes this reference to do a java method callback to determine the
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* number of elements in the linked list
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*/
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JNIEXPORT jint JNICALL
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Java_gc_gctests_nativeGC01_nativeGC01_nativeMethod01
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(JNIEnv *env, jobject obj, jobject linked_list) {
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jclass cls, clss;
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jmethodID mid, mid2;
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int elementCount;
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/* Before doing anything force a GC by
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invoking a callback where System.gc() is called
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*/
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cls = (*env)->GetObjectClass(env, obj);
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mid = (*env)->GetMethodID(env, cls, "callbackGC", "()V");
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if (mid == 0) {
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printf("couldnt locate method callbackGC()");
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return -1;
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}
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(*env)->CallVoidMethod(env,obj,mid);
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/* Now that a GC has been done, invoke the callback
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that counts the number of elements in the
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circular linked list
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*/
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clss = (*env)->GetObjectClass(env, linked_list);
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mid2 = (*env)->GetMethodID(env, clss, "getLength", "()I" );
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if (mid2 == 0) {
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printf("couldnt locate method getLength()");
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return -1;
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}
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elementCount = (*env)->CallIntMethod(env, linked_list, mid2);
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return elementCount;
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}
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