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/*
* Copyright (c) 2004, 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.
*/
/* @test
* @bug 5004077 8203765
* @summary Check blocking of select and close
*/
import java.io.IOException;
import java.lang.management.ManagementFactory;
import java.lang.management.MonitorInfo;
import java.lang.management.ThreadInfo;
import java.nio.channels.Selector;
public class SelectAndClose {
static Selector selector;
static volatile boolean awakened = false;
private static boolean mightHoldLock(Thread t, Object lock) {
long tid = t.getId();
int hash = System.identityHashCode(lock);
ThreadInfo ti = ManagementFactory.getThreadMXBean().
getThreadInfo(new long[]{ tid} , true, false, 100)[0];
if (ti != null) {
for (MonitorInfo mi : ti.getLockedMonitors()) {
if (mi.getIdentityHashCode() == hash)
return true;
}
}
return false;
}
public static void main(String[] args) throws Exception {
selector = Selector.open();
// Create and start a selector in a separate thread.
Thread selectThread = new Thread(new Runnable() {
public void run() {
try {
selector.select();
awakened = true;
} catch (IOException e) {
e.printStackTrace();
}
}
});
selectThread.start();
// Spin until the monitor of the selected-key set is likely held
// as selected operations are specified to synchronize on the
// selected-key set.
while (!mightHoldLock(selectThread, selector.selectedKeys())) {
Thread.sleep(50);
}
// Close the selector.
selector.close();
if (!awakened)
selector.wakeup();
// Wait for select() thread to finish.
selectThread.join();
if (!awakened) {
throw new RuntimeException("Select did not awaken!");
}
}
}
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