| /* |
| * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package gc.g1.unloading.keepref; |
| |
| import gc.g1.unloading.check.cleanup.CleanupAction; |
| import gc.g1.unloading.loading.LibLoader; |
| |
| /** |
| * This holder keeps reference through JNI local reference. |
| */ |
| public class JNILocalRefHolder implements RefHolder { |
| |
| static { |
| //Force loading library |
| new LibLoader().hashCode(); |
| } |
| |
| // We use this field to transfer object into native JNI call. Idea is to avoid transferring link through method |
| // arguments. |
| private Object objectToKeep; |
| |
| private native void holdWithJNILocalReference(Object syncObject); |
| |
| @Override |
| public Object hold(Object object) { |
| objectToKeep = object; |
| final Object syncObject = new Object(); |
| Thread keepingThread = new Thread(new Runnable() { |
| @Override |
| public void run() { |
| synchronized (syncObject) { |
| holdWithJNILocalReference(syncObject); |
| } |
| } |
| }); |
| keepingThread.setDaemon(true); |
| keepingThread.start(); |
| return new CleanupAction() { |
| @Override |
| public void cleanup() throws Exception { |
| synchronized (syncObject) { |
| syncObject.notify(); |
| } |
| } |
| }; |
| } |
| |
| |
| } |