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* This code is free software; you can redistribute it and/or modify it
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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
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*
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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.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
/*
* @test
* @bug 4530538
* @summary Basic unit test of ThreadMXBean.getAllThreadIds()
* @author Alexei Guibadoulline and Mandy Chung
*
* @key intermittent
* @modules java.management
* @run main/othervm AllThreadIds
*/
import java.lang.management.*;
import java.time.Instant;
import java.util.concurrent.Phaser;
import java.util.function.Supplier;
public class AllThreadIds {
/**
* A supplier wrapper for the delayed format printing.
* The supplied value will have to be formatted as <em>$s</em>
* @param <T> The wrapped type
*/
private static final class ArgWrapper<T> {
private final Supplier<T> val;
public ArgWrapper(Supplier<T> val) {
this.val = val;
}
@Override
public String toString() {
T resolved = val.get();
return resolved != null ? resolved.toString() : null;
}
}
static final int DAEMON_THREADS = 20;
static final int USER_THREADS = 5;
static final int ALL_THREADS = DAEMON_THREADS + USER_THREADS;
private static final boolean live[] = new boolean[ALL_THREADS];
private static final Thread allThreads[] = new Thread[ALL_THREADS];
private static final 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 final Phaser startupCheck = new Phaser(ALL_THREADS + 1);
private static void printThreadList() {
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 checkInitialState() throws Exception {
updateCounters();
checkThreadCount(0, 0);
}
private static void checkAllThreadsAlive() throws Exception {
updateCounters();
// Start all threads and wait to be sure they all are alive
for (int i = 0; i < ALL_THREADS; i++) {
setLive(i, true);
allThreads[i] = new MyThread(i);
allThreads[i].setDaemon(i < DAEMON_THREADS);
allThreads[i].start();
}
// wait until all threads are started.
startupCheck.arriveAndAwaitAdvance();
checkThreadCount(ALL_THREADS, 0);
if (trace) {
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();
}
}
private static void checkDaemonThreadsDead() throws Exception {
updateCounters();
// Stop daemon threads, wait to be sure they all are dead, and check
// that they disappeared from getAllThreadIds() list
for (int i = 0; i < DAEMON_THREADS; i++) {
setLive(i, false);
}
// make sure the daemon threads are completely dead
joinDaemonThreads();
// and check the reported thread count
checkThreadCount(0, DAEMON_THREADS);
// Check mbean now
long[] list = mbean.getAllThreadIds();
for (int i = 0; i < ALL_THREADS; i++) {
long expectedId = allThreads[i].getId();
boolean found = false;
boolean alive = (i >= DAEMON_THREADS);
if (trace) {
System.out.print("Looking for thread with id " + expectedId +
(alive ? " expected alive." : " expected terminated."));
}
for (int j = 0; j < list.length; j++) {
if (expectedId == list[j]) {
found = true;
break;
}
}
if (alive != found) {
testFailed = true;
}
if (trace) {
if (alive != found) {
System.out.println(" TEST FAILED.");
} else {
System.out.println();
}
}
}
}
private static void checkAllThreadsDead() throws Exception {
updateCounters();
// Stop all threads and wait to be sure they all are dead
for (int i = DAEMON_THREADS; i < ALL_THREADS; i++) {
setLive(i, false);
}
// make sure the non-daemon threads are completely dead
joinNonDaemonThreads();
// and check the thread count
checkThreadCount(0, ALL_THREADS - DAEMON_THREADS);
}
private static void checkThreadCount(int numNewThreads,
int numTerminatedThreads)
throws Exception {
checkLiveThreads(numNewThreads, numTerminatedThreads);
checkPeakThreads(numNewThreads);
checkTotalThreads(numNewThreads);
checkThreadIds();
}
private static void checkLiveThreads(int numNewThreads,
int numTerminatedThreads)
throws InterruptedException {
int diff = numNewThreads - numTerminatedThreads;
waitTillEquals(
diff + prevLiveThreadCount,
()->(long)mbean.getThreadCount(),
"Unexpected number of live threads: " +
" Prev live = %1$d Current live = ${provided} Threads added = %2$d" +
" Threads terminated = %3$d",
()->prevLiveThreadCount,
()->numNewThreads,
()->numTerminatedThreads
);
}
private static void checkPeakThreads(int numNewThreads)
throws InterruptedException {
waitTillEquals(numNewThreads + prevPeakThreadCount,
()->(long)mbean.getPeakThreadCount(),
"Unexpected number of peak threads: " +
" Prev peak = %1$d Current peak = ${provided} Threads added = %2$d",
()->prevPeakThreadCount,
()->numNewThreads
);
}
private static void checkTotalThreads(int numNewThreads)
throws InterruptedException {
waitTillEquals(numNewThreads + prevTotalThreadCount,
()->mbean.getTotalStartedThreadCount(),
"Unexpected number of total threads: " +
" Prev Total = %1$d Current Total = ${provided} Threads added = %2$d",
()->prevTotalThreadCount,
()->numNewThreads
);
}
private static void checkThreadIds() throws InterruptedException {
long[] list = mbean.getAllThreadIds();
waitTillEquals(
list.length,
()->(long)mbean.getThreadCount(),
"Array length returned by " +
"getAllThreadIds() = %1$d not matched count = ${provided}",
()->list.length
);
}
/**
* Waits till the <em>expectedVal</em> equals to the <em>retrievedVal</em>.
* It will report a status message on the first occasion of the value mismatch
* and then, subsequently, when the <em>retrievedVal</em> value changes.
* @param expectedVal The value to wait for
* @param retrievedVal The supplier of the value to check against the <em>expectedVal</em>
* @param msgFormat The formatted message to be printed in case of mismatch
* @param msgArgs The parameters to the formatted message
* @throws InterruptedException
*/
private static void waitTillEquals(long expectedVal, Supplier<Long> retrievedVal,
String msgFormat, Supplier<Object> ... msgArgs)
throws InterruptedException {
Object[] args = null;
long countPrev = -1;
while (true) {
Long count = retrievedVal.get();
if (count == expectedVal) break;
if (countPrev == -1 || countPrev != count) {
if (args == null) {
args = new Object[msgArgs.length];
for(int i=0; i < msgArgs.length; i++) {
args[i] = new ArgWrapper<>((Supplier<Object>)msgArgs[i]);
}
}
System.err.format("TS: %s\n", Instant.now());
System.err.format(
msgFormat
.replace("${provided}", String.valueOf(count))
.replace("$d", "$s"),
args
).flush();
printThreadList();
System.err.println("\nRetrying ...\n");
}
countPrev = count;
Thread.sleep(1);
}
}
private static void updateCounters() {
prevTotalThreadCount = mbean.getTotalStartedThreadCount();
prevLiveThreadCount = mbean.getThreadCount();
prevPeakThreadCount = mbean.getPeakThreadCount();
}
public static void main(String args[]) throws Exception {
if (args.length > 0 && args[0].equals("trace")) {
trace = true;
}
checkInitialState();
checkAllThreadsAlive();
checkDaemonThreadsDead();
checkAllThreadsDead();
if (testFailed)
throw new RuntimeException("TEST FAILED.");
System.out.println("Test passed.");
}
private static void joinDaemonThreads() throws InterruptedException {
for (int i = 0; i < DAEMON_THREADS; i++) {
allThreads[i].join();
}
}
private static void joinNonDaemonThreads() throws InterruptedException {
for (int i = DAEMON_THREADS; i < ALL_THREADS; i++) {
allThreads[i].join();
}
}
private static void setLive(int i, boolean val) {
synchronized(live) {
live[i] = val;
}
}
private static boolean isLive(int i) {
synchronized(live) {
return live[i];
}
}
// 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
startupCheck.arrive();
while (isLive(id)) {
try {
sleep(100);
} catch (InterruptedException e) {
System.out.println("Unexpected exception is thrown.");
e.printStackTrace(System.out);
testFailed = true;
}
}
}
}
}