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*
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* 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).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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/*
* @test
* @bug 4530538
* @summary Basic unit test of ThreadMXBean.getAllThreadIds()
* @author Alexei Guibadoulline and Mandy Chung
*
* @run build Barrier
* @run main/othervm AllThreadIds
*/
import java.lang.management.*;
import java.util.*;
public class AllThreadIds {
final static int DAEMON_THREADS = 20;
final static int USER_THREADS = 5;
final static int ALL_THREADS = DAEMON_THREADS + USER_THREADS;
private static volatile boolean live[] = new boolean[ALL_THREADS];
private static Thread allThreads[] = new Thread[ALL_THREADS];
private static ThreadMXBean mbean
= ManagementFactory.getThreadMXBean();
private static boolean testFailed = false;
private static boolean trace = false;
private static long prevTotalThreadCount = 0;
private static int prevLiveThreadCount = 0;
private static int prevPeakThreadCount = 0;
private static long curTotalThreadCount = 0;
private static int curLiveThreadCount = 0;
private static int curPeakThreadCount = 0;
// barrier for threads communication
private static Barrier barrier = new Barrier(ALL_THREADS);
private static void printThreadList() {
if (!trace) return;
long[] list = mbean.getAllThreadIds();
for (int i = 1; i <= list.length; i++) {
System.out.println(i + ": Thread id = " + list[i-1]);
}
for (int i = 0; i < ALL_THREADS; i++) {
Thread t = allThreads[i];
System.out.println(t.getName() + " Id = " + t.getId() +
" die = " + live[i] +
" alive = " + t.isAlive());
}
}
private static void fail(String msg) {
trace = true;
printThreadList();
throw new RuntimeException(msg);
}
private static void checkThreadCount(int numNewThreads,
int numTerminatedThreads)
throws Exception {
prevTotalThreadCount = curTotalThreadCount;
prevLiveThreadCount = curLiveThreadCount;
prevPeakThreadCount = curPeakThreadCount;
curTotalThreadCount = mbean.getTotalStartedThreadCount();
curLiveThreadCount = mbean.getThreadCount();
curPeakThreadCount = mbean.getPeakThreadCount();
if ((curLiveThreadCount - prevLiveThreadCount) !=
(numNewThreads - numTerminatedThreads)) {
fail("Unexpected number of live threads: " +
" Prev live = " + prevLiveThreadCount +
" Current live = " + curLiveThreadCount +
" Threads added = " + numNewThreads +
" Threads terminated = " + numTerminatedThreads);
}
if (curPeakThreadCount - prevPeakThreadCount != numNewThreads) {
fail("Unexpected number of peak threads: " +
" Prev peak = " + prevPeakThreadCount +
" Current peak = " + curPeakThreadCount +
" Threads added = " + numNewThreads);
}
if (curTotalThreadCount - prevTotalThreadCount != numNewThreads) {
fail("Unexpected number of total threads: " +
" Prev Total = " + prevTotalThreadCount +
" Current Total = " + curTotalThreadCount +
" Threads added = " + numNewThreads);
}
long[] list = mbean.getAllThreadIds();
if (list.length != curLiveThreadCount) {
fail("Array length returned by " +
"getAllThreadIds() = " + list.length +
" not matched count = " + curLiveThreadCount);
}
}
public static void main(String args[]) throws Exception {
if (args.length > 0 && args[0].equals("trace")) {
trace = true;
}
curTotalThreadCount = mbean.getTotalStartedThreadCount();
curLiveThreadCount = mbean.getThreadCount();
curPeakThreadCount = mbean.getPeakThreadCount();
checkThreadCount(0, 0);
// Start all threads and wait to be sure they all are alive
barrier.set(ALL_THREADS);
for (int i = 0; i < ALL_THREADS; i++) {
live[i] = true;
allThreads[i] = new MyThread(i);
allThreads[i].setDaemon( (i < DAEMON_THREADS) ? true : false);
allThreads[i].start();
}
// wait until all threads are started.
barrier.await();
checkThreadCount(ALL_THREADS, 0);
printThreadList();
// Check mbean now. All threads must appear in getAllThreadIds() list
long[] list = mbean.getAllThreadIds();
for (int i = 0; i < ALL_THREADS; i++) {
long expectedId = allThreads[i].getId();
boolean found = false;
if (trace) {
System.out.print("Looking for thread with id " + expectedId);
}
for (int j = 0; j < list.length; j++) {
if (expectedId == list[j]) {
found = true;
break;
}
}
if (!found) {
testFailed = true;
}
if (trace) {
if (!found) {
System.out.print(". TEST FAILED.");
}
System.out.println();
}
}
if (trace) {
System.out.println();
}
// Stop daemon threads, wait to be sure they all are dead, and check
// that they disappeared from getAllThreadIds() list
barrier.set(DAEMON_THREADS);
for (int i = 0; i < DAEMON_THREADS; i++) {
live[i] = false;
}
// wait until daemon threads are terminated.
barrier.await();
// give chance to threads to terminate
pause();
checkThreadCount(0, DAEMON_THREADS);
// Check mbean now
list = mbean.getAllThreadIds();
for (int i = 0; i < ALL_THREADS; i++) {
long expectedId = allThreads[i].getId();
boolean found = false;
boolean live = (i >= DAEMON_THREADS);
if (trace) {
System.out.print("Looking for thread with id " + expectedId +
(live ? " expected alive." : " expected terminated."));
}
for (int j = 0; j < list.length; j++) {
if (expectedId == list[j]) {
found = true;
break;
}
}
if (live != found) {
testFailed = true;
}
if (trace) {
if (live != found) {
System.out.println(" TEST FAILED.");
} else {
System.out.println();
}
}
}
// Stop all threads and wait to be sure they all are dead
barrier.set(ALL_THREADS - DAEMON_THREADS);
for (int i = DAEMON_THREADS; i < ALL_THREADS; i++) {
live[i] = false;
}
// wait until daemon threads are terminated .
barrier.await();
// give chance to threads to terminate
pause();
checkThreadCount(0, ALL_THREADS - DAEMON_THREADS);
if (testFailed)
throw new RuntimeException("TEST FAILED.");
System.out.println("Test passed.");
}
// The MyThread thread lives as long as correspondent live[i] value is true
private static class MyThread extends Thread {
int id;
MyThread(int id) {
this.id = id;
}
public void run() {
// signal started
barrier.signal();
while (live[id]) {
try {
sleep(100);
} catch (InterruptedException e) {
System.out.println("Unexpected exception is thrown.");
e.printStackTrace(System.out);
testFailed = true;
}
}
// signal about to exit
barrier.signal();
}
}
private static Object pauseObj = new Object();
private static void pause() {
// Enter lock a without blocking
synchronized (pauseObj) {
try {
// may need to tune this timeout for different platforms
pauseObj.wait(50);
} catch (Exception e) {
System.err.println("Unexpected exception.");
e.printStackTrace(System.err);
}
}
}
}