1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
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  23 
  24 /*
  25  * @test
  26  * @bug     4530538
  27  * @key intermittent
  28  * @summary Basic unit test of ThreadMXBean.getAllThreadIds()
  29  * @author  Alexei Guibadoulline and Mandy Chung
  30  *
  31  * @run main/othervm AllThreadIds
  32  */
  33 
  34 import java.lang.management.*;
  35 import java.time.Instant;
  36 import java.util.concurrent.Phaser;
  37 import java.util.function.Supplier;
  38 
  39 public class AllThreadIds {
  40     /**
  41      * A supplier wrapper for the delayed format printing.
  42      * The supplied value will have to be formatted as <em>$s</em>
  43      * @param <T> The wrapped type
  44      */
  45     private static final class ArgWrapper<T> {
  46         private final Supplier<T> val;
  47 
  48         public ArgWrapper(Supplier<T> val) {
  49             this.val = val;
  50         }
  51 
  52         @Override
  53         public String toString() {
  54             T resolved = val.get();
  55             return resolved != null ? resolved.toString() : null;
  56         }
  57     }
  58 
  59     static final int DAEMON_THREADS = 20;
  60     static final int USER_THREADS = 5;
  61     static final int ALL_THREADS = DAEMON_THREADS + USER_THREADS;
  62     private static final boolean live[] = new boolean[ALL_THREADS];
  63     private static final Thread allThreads[] = new Thread[ALL_THREADS];
  64     private static final ThreadMXBean mbean = ManagementFactory.getThreadMXBean();
  65     private static boolean testFailed = false;
  66     private static boolean trace = false;
  67 
  68     private static long prevTotalThreadCount = 0;
  69     private static int prevLiveThreadCount = 0;
  70     private static int prevPeakThreadCount = 0;
  71 
  72     private static final Phaser startupCheck = new Phaser(ALL_THREADS + 1);
  73 
  74     private static void printThreadList() {
  75         long[] list = mbean.getAllThreadIds();
  76         for (int i = 1; i <= list.length; i++) {
  77             System.out.println(i + ": Thread id = " + list[i-1]);
  78         }
  79         for (int i = 0; i < ALL_THREADS; i++) {
  80             Thread t = allThreads[i];
  81             System.out.println(t.getName() + " Id = " + t.getId() +
  82                 " die = " + live[i] +
  83                 " alive = " + t.isAlive());
  84         }
  85     }
  86 
  87     private static void checkInitialState() throws Exception {
  88         updateCounters();
  89         checkThreadCount(0, 0);
  90     }
  91 
  92     private static void checkAllThreadsAlive() throws Exception {
  93         updateCounters();
  94 
  95         // Start all threads and wait to be sure they all are alive
  96         for (int i = 0; i < ALL_THREADS; i++) {
  97             setLive(i, true);
  98             allThreads[i] = new MyThread(i);
  99             allThreads[i].setDaemon(i < DAEMON_THREADS);
 100             allThreads[i].start();
 101         }
 102         // wait until all threads are started.
 103         startupCheck.arriveAndAwaitAdvance();
 104 
 105         checkThreadCount(ALL_THREADS, 0);
 106         if (trace) {
 107             printThreadList();
 108         }
 109         // Check mbean now. All threads must appear in getAllThreadIds() list
 110         long[] list = mbean.getAllThreadIds();
 111 
 112         for (int i = 0; i < ALL_THREADS; i++) {
 113             long expectedId = allThreads[i].getId();
 114             boolean found = false;
 115 
 116             if (trace) {
 117                 System.out.print("Looking for thread with id " + expectedId);
 118             }
 119             for (int j = 0; j < list.length; j++) {
 120                 if (expectedId == list[j]) {
 121                     found = true;
 122                     break;
 123                 }
 124             }
 125 
 126             if (!found) {
 127                 testFailed = true;
 128             }
 129             if (trace) {
 130                 if (!found) {
 131                     System.out.print(". TEST FAILED.");
 132                 }
 133                 System.out.println();
 134             }
 135         }
 136         if (trace) {
 137             System.out.println();
 138         }
 139     }
 140 
 141     private static void checkDaemonThreadsDead() throws Exception {
 142         updateCounters();
 143 
 144         // Stop daemon threads, wait to be sure they all are dead, and check
 145         // that they disappeared from getAllThreadIds() list
 146         for (int i = 0; i < DAEMON_THREADS; i++) {
 147             setLive(i, false);
 148         }
 149 
 150         // make sure the daemon threads are completely dead
 151         joinDaemonThreads();
 152 
 153         // and check the reported thread count
 154         checkThreadCount(0, DAEMON_THREADS);
 155 
 156         // Check mbean now
 157         long[] list = mbean.getAllThreadIds();
 158 
 159         for (int i = 0; i < ALL_THREADS; i++) {
 160             long expectedId = allThreads[i].getId();
 161             boolean found = false;
 162             boolean alive = (i >= DAEMON_THREADS);
 163 
 164             if (trace) {
 165                 System.out.print("Looking for thread with id " + expectedId +
 166                     (alive ? " expected alive." : " expected terminated."));
 167             }
 168             for (int j = 0; j < list.length; j++) {
 169                 if (expectedId == list[j]) {
 170                     found = true;
 171                     break;
 172                 }
 173             }
 174 
 175             if (alive != found) {
 176                 testFailed = true;
 177             }
 178             if (trace) {
 179                 if (alive != found) {
 180                     System.out.println(" TEST FAILED.");
 181                 } else {
 182                     System.out.println();
 183                 }
 184             }
 185         }
 186     }
 187 
 188     private static void checkAllThreadsDead() throws Exception {
 189         updateCounters();
 190 
 191         // Stop all threads and wait to be sure they all are dead
 192         for (int i = DAEMON_THREADS; i < ALL_THREADS; i++) {
 193             setLive(i, false);
 194         }
 195 
 196         // make sure the non-daemon threads are completely dead
 197         joinNonDaemonThreads();
 198 
 199         // and check the thread count
 200         checkThreadCount(0, ALL_THREADS - DAEMON_THREADS);
 201     }
 202 
 203     private static void checkThreadCount(int numNewThreads,
 204                                          int numTerminatedThreads)
 205         throws Exception {
 206 
 207         checkLiveThreads(numNewThreads, numTerminatedThreads);
 208         checkPeakThreads(numNewThreads);
 209         checkTotalThreads(numNewThreads);
 210         checkThreadIds();
 211     }
 212 
 213     private static void checkLiveThreads(int numNewThreads,
 214                                          int numTerminatedThreads)
 215         throws InterruptedException {
 216         int diff = numNewThreads - numTerminatedThreads;
 217 
 218         waitTillEquals(
 219             diff + prevLiveThreadCount,
 220             ()->(long)mbean.getThreadCount(),
 221             "Unexpected number of live threads: " +
 222                 " Prev live = %1$d Current live = ${provided} Threads added = %2$d" +
 223                 " Threads terminated = %3$d",
 224             ()->prevLiveThreadCount,
 225             ()->numNewThreads,
 226             ()->numTerminatedThreads
 227         );
 228     }
 229 
 230     private static void checkPeakThreads(int numNewThreads)
 231         throws InterruptedException {
 232 
 233         waitTillEquals(numNewThreads + prevPeakThreadCount,
 234             ()->(long)mbean.getPeakThreadCount(),
 235             "Unexpected number of peak threads: " +
 236                 " Prev peak = %1$d Current peak = ${provided} Threads added = %2$d",
 237             ()->prevPeakThreadCount,
 238             ()->numNewThreads
 239         );
 240     }
 241 
 242     private static void checkTotalThreads(int numNewThreads)
 243         throws InterruptedException {
 244 
 245         waitTillEquals(numNewThreads + prevTotalThreadCount,
 246             ()->mbean.getTotalStartedThreadCount(),
 247             "Unexpected number of total threads: " +
 248                 " Prev Total = %1$d Current Total = ${provided} Threads added = %2$d",
 249             ()->prevTotalThreadCount,
 250             ()->numNewThreads
 251         );
 252     }
 253 
 254     private static void checkThreadIds() throws InterruptedException {
 255         long[] list = mbean.getAllThreadIds();
 256 
 257         waitTillEquals(
 258             list.length,
 259             ()->(long)mbean.getThreadCount(),
 260             "Array length returned by " +
 261                 "getAllThreadIds() = %1$d not matched count = ${provided}",
 262             ()->list.length
 263         );
 264     }
 265 
 266     /**
 267      * Waits till the <em>expectedVal</em> equals to the <em>retrievedVal</em>.
 268      * It will report a status message on the first occasion of the value mismatch
 269      * and then, subsequently, when the <em>retrievedVal</em> value changes.
 270      * @param expectedVal The value to wait for
 271      * @param retrievedVal The supplier of the value to check against the <em>expectedVal</em>
 272      * @param msgFormat The formatted message to be printed in case of mismatch
 273      * @param msgArgs The parameters to the formatted message
 274      * @throws InterruptedException
 275      */
 276     private static void waitTillEquals(long expectedVal, Supplier<Long> retrievedVal,
 277                                         String msgFormat, Supplier<Object> ... msgArgs)
 278         throws InterruptedException {
 279         Object[] args = null;
 280 
 281         long countPrev = -1;
 282         while (true) {
 283             Long count = retrievedVal.get();
 284             if (count == expectedVal) break;
 285             if (countPrev == -1 || countPrev != count) {
 286                 if (args == null) {
 287                     args = new Object[msgArgs.length];
 288                     for(int i=0; i < msgArgs.length; i++) {
 289                         args[i] = new ArgWrapper<>((Supplier<Object>)msgArgs[i]);
 290                     }
 291                 }
 292                 System.err.format("TS: %s\n", Instant.now());
 293                 System.err.format(
 294                     msgFormat
 295                         .replace("${provided}", String.valueOf(count))
 296                         .replace("$d", "$s"),
 297                     args
 298                 ).flush();
 299                 printThreadList();
 300                 System.err.println("\nRetrying ...\n");
 301             }
 302             countPrev = count;
 303             Thread.sleep(1);
 304         }
 305     }
 306 
 307     private static void updateCounters() {
 308         prevTotalThreadCount = mbean.getTotalStartedThreadCount();
 309         prevLiveThreadCount = mbean.getThreadCount();
 310         prevPeakThreadCount = mbean.getPeakThreadCount();
 311     }
 312 
 313     public static void main(String args[]) throws Exception {
 314         if (args.length > 0 && args[0].equals("trace")) {
 315             trace = true;
 316         }
 317 
 318         checkInitialState();
 319         checkAllThreadsAlive();
 320         checkDaemonThreadsDead();
 321         checkAllThreadsDead();
 322 
 323         if (testFailed)
 324             throw new RuntimeException("TEST FAILED.");
 325 
 326         System.out.println("Test passed.");
 327     }
 328 
 329     private static void joinDaemonThreads() throws InterruptedException {
 330         for (int i = 0; i < DAEMON_THREADS; i++) {
 331             allThreads[i].join();
 332         }
 333     }
 334 
 335     private static void joinNonDaemonThreads() throws InterruptedException {
 336         for (int i = DAEMON_THREADS; i < ALL_THREADS; i++) {
 337             allThreads[i].join();
 338         }
 339     }
 340 
 341     private static void setLive(int i, boolean val) {
 342         synchronized(live) {
 343             live[i] = val;
 344         }
 345     }
 346 
 347     private static boolean isLive(int i) {
 348         synchronized(live) {
 349             return live[i];
 350         }
 351     }
 352 
 353     // The MyThread thread lives as long as correspondent live[i] value is true
 354     private static class MyThread extends Thread {
 355         int id;
 356 
 357         MyThread(int id) {
 358             this.id = id;
 359         }
 360 
 361         public void run() {
 362             // signal started
 363             startupCheck.arrive();
 364             while (isLive(id)) {
 365                 try {
 366                     sleep(100);
 367                 } catch (InterruptedException e) {
 368                     System.out.println("Unexpected exception is thrown.");
 369                     e.printStackTrace(System.out);
 370                     testFailed = true;
 371                 }
 372             }
 373         }
 374     }
 375 }