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| 1 | +/* | |
| 2 | + * Copyright (c) 2003, 2008, Oracle and/or its affiliates. All rights reserved. | |
| 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. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle in the LICENSE file that accompanied this code. | |
| 10 | + * | |
| 11 | + * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 12 | + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 | + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 | + * version 2 for more details (a copy is included in the LICENSE file that | |
| 15 | + * accompanied this code). | |
| 16 | + * | |
| 17 | + * You should have received a copy of the GNU General Public License version | |
| 18 | + * 2 along with this work; if not, write to the Free Software Foundation, | |
| 19 | + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 | + * | |
| 21 | + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | + | |
| 26 | +package java.lang.management; | |
| 27 | + | |
| 28 | +import java.util.Map; | |
| 29 | + | |
| 30 | +/** | |
| 31 | + * The management interface for the thread system of | |
| 32 | + * the Java virtual machine. | |
| 33 | + * | |
| 34 | + * <p> A Java virtual machine has a single instance of the implementation | |
| 35 | + * class of this interface. This instance implementing this interface is | |
| 36 | + * an <a href="ManagementFactory.html#MXBean">MXBean</a> | |
| 37 | + * that can be obtained by calling | |
| 38 | + * the {@link ManagementFactory#getThreadMXBean} method or | |
| 39 | + * from the {@link ManagementFactory#getPlatformMBeanServer | |
| 40 | + * platform <tt>MBeanServer</tt>} method. | |
| 41 | + * | |
| 42 | + * <p>The <tt>ObjectName</tt> for uniquely identifying the MXBean for | |
| 43 | + * the thread system within an MBeanServer is: | |
| 44 | + * <blockquote> | |
| 45 | + * {@link ManagementFactory#THREAD_MXBEAN_NAME | |
| 46 | + * <tt>java.lang:type=Threading</tt>} | |
| 47 | + * </blockquote> | |
| 48 | + * | |
| 49 | + * It can be obtained by calling the | |
| 50 | + * {@link PlatformManagedObject#getObjectName} method. | |
| 51 | + * | |
| 52 | + * <h4>Thread ID</h4> | |
| 53 | + * Thread ID is a positive long value returned by calling the | |
| 54 | + * {@link java.lang.Thread#getId} method for a thread. | |
| 55 | + * The thread ID is unique during its lifetime. When a thread | |
| 56 | + * is terminated, this thread ID may be reused. | |
| 57 | + * | |
| 58 | + * <p> Some methods in this interface take a thread ID or an array | |
| 59 | + * of thread IDs as the input parameter and return per-thread information. | |
| 60 | + * | |
| 61 | + * <h4>Thread CPU time</h4> | |
| 62 | + * A Java virtual machine implementation may support measuring | |
| 63 | + * the CPU time for the current thread, for any thread, or for no threads. | |
| 64 | + * | |
| 65 | + * <p> | |
| 66 | + * The {@link #isThreadCpuTimeSupported} method can be used to determine | |
| 67 | + * if a Java virtual machine supports measuring of the CPU time for any | |
| 68 | + * thread. The {@link #isCurrentThreadCpuTimeSupported} method can | |
| 69 | + * be used to determine if a Java virtual machine supports measuring of | |
| 70 | + * the CPU time for the current thread. | |
| 71 | + * A Java virtual machine implementation that supports CPU time measurement | |
| 72 | + * for any thread will also support that for the current thread. | |
| 73 | + * | |
| 74 | + * <p> The CPU time provided by this interface has nanosecond precision | |
| 75 | + * but not necessarily nanosecond accuracy. | |
| 76 | + * | |
| 77 | + * <p> | |
| 78 | + * A Java virtual machine may disable CPU time measurement | |
| 79 | + * by default. | |
| 80 | + * The {@link #isThreadCpuTimeEnabled} and {@link #setThreadCpuTimeEnabled} | |
| 81 | + * methods can be used to test if CPU time measurement is enabled | |
| 82 | + * and to enable/disable this support respectively. | |
| 83 | + * Enabling thread CPU measurement could be expensive in some | |
| 84 | + * Java virtual machine implementations. | |
| 85 | + * | |
| 86 | + * <h4>Thread Contention Monitoring</h4> | |
| 87 | + * Some Java virtual machines may support thread contention monitoring. | |
| 88 | + * When thread contention monitoring is enabled, the accumulated elapsed | |
| 89 | + * time that the thread has blocked for synchronization or waited for | |
| 90 | + * notification will be collected and returned in the | |
| 91 | + * <a href="ThreadInfo.html#SyncStats"><tt>ThreadInfo</tt></a> object. | |
| 92 | + * <p> | |
| 93 | + * The {@link #isThreadContentionMonitoringSupported} method can be used to | |
| 94 | + * determine if a Java virtual machine supports thread contention monitoring. | |
| 95 | + * The thread contention monitoring is disabled by default. The | |
| 96 | + * {@link #setThreadContentionMonitoringEnabled} method can be used to enable | |
| 97 | + * thread contention monitoring. | |
| 98 | + * | |
| 99 | + * <h4>Synchronization Information and Deadlock Detection</h4> | |
| 100 | + * Some Java virtual machines may support monitoring of | |
| 101 | + * {@linkplain #isObjectMonitorUsageSupported object monitor usage} and | |
| 102 | + * {@linkplain #isSynchronizerUsageSupported ownable synchronizer usage}. | |
| 103 | + * The {@link #getThreadInfo(long[], boolean, boolean)} and | |
| 104 | + * {@link #dumpAllThreads} methods can be used to obtain the thread stack trace | |
| 105 | + * and synchronization information including which | |
| 106 | + * {@linkplain LockInfo <i>lock</i>} a thread is blocked to | |
| 107 | + * acquire or waiting on and which locks the thread currently owns. | |
| 108 | + * <p> | |
| 109 | + * The <tt>ThreadMXBean</tt> interface provides the | |
| 110 | + * {@link #findMonitorDeadlockedThreads} and | |
| 111 | + * {@link #findDeadlockedThreads} methods to find deadlocks in | |
| 112 | + * the running application. | |
| 113 | + * | |
| 114 | + * @see ManagementFactory#getPlatformMXBeans(Class) | |
| 115 | + * @see <a href="../../../javax/management/package-summary.html"> | |
| 116 | + * JMX Specification.</a> | |
| 117 | + * @see <a href="package-summary.html#examples"> | |
| 118 | + * Ways to Access MXBeans</a> | |
| 119 | + * | |
| 120 | + * @author Mandy Chung | |
| 121 | + * @since 1.5 | |
| 122 | + */ | |
| 123 | + | |
| 124 | +public interface ThreadMXBean extends PlatformManagedObject { | |
| 125 | + /** | |
| 126 | + * Returns the current number of live threads including both | |
| 127 | + * daemon and non-daemon threads. | |
| 128 | + * | |
| 129 | + * @return the current number of live threads. | |
| 130 | + */ | |
| 131 | + public int getThreadCount(); | |
| 132 | + | |
| 133 | + /** | |
| 134 | + * Returns the peak live thread count since the Java virtual machine | |
| 135 | + * started or peak was reset. | |
| 136 | + * | |
| 137 | + * @return the peak live thread count. | |
| 138 | + */ | |
| 139 | + public int getPeakThreadCount(); | |
| 140 | + | |
| 141 | + /** | |
| 142 | + * Returns the total number of threads created and also started | |
| 143 | + * since the Java virtual machine started. | |
| 144 | + * | |
| 145 | + * @return the total number of threads started. | |
| 146 | + */ | |
| 147 | + public long getTotalStartedThreadCount(); | |
| 148 | + | |
| 149 | + /** | |
| 150 | + * Returns the current number of live daemon threads. | |
| 151 | + * | |
| 152 | + * @return the current number of live daemon threads. | |
| 153 | + */ | |
| 154 | + public int getDaemonThreadCount(); | |
| 155 | + | |
| 156 | + /** | |
| 157 | + * Returns all live thread IDs. | |
| 158 | + * Some threads included in the returned array | |
| 159 | + * may have been terminated when this method returns. | |
| 160 | + * | |
| 161 | + * @return an array of <tt>long</tt>, each is a thread ID. | |
| 162 | + * | |
| 163 | + * @throws java.lang.SecurityException if a security manager | |
| 164 | + * exists and the caller does not have | |
| 165 | + * ManagementPermission("monitor"). | |
| 166 | + */ | |
| 167 | + public long[] getAllThreadIds(); | |
| 168 | + | |
| 169 | + /** | |
| 170 | + * Returns the thread info for a thread of the specified | |
| 171 | + * <tt>id</tt> with no stack trace. | |
| 172 | + * This method is equivalent to calling: | |
| 173 | + * <blockquote> | |
| 174 | + * {@link #getThreadInfo(long, int) getThreadInfo(id, 0);} | |
| 175 | + * </blockquote> | |
| 176 | + * | |
| 177 | + * <p> | |
| 178 | + * This method returns a <tt>ThreadInfo</tt> object representing | |
| 179 | + * the thread information for the thread of the specified ID. | |
| 180 | + * The stack trace, locked monitors, and locked synchronizers | |
| 181 | + * in the returned <tt>ThreadInfo</tt> object will | |
| 182 | + * be empty. | |
| 183 | + * | |
| 184 | + * If a thread of the given ID is not alive or does not exist, | |
| 185 | + * this method will return <tt>null</tt>. A thread is alive if | |
| 186 | + * it has been started and has not yet died. | |
| 187 | + * | |
| 188 | + * <p> | |
| 189 | + * <b>MBeanServer access</b>:<br> | |
| 190 | + * The mapped type of <tt>ThreadInfo</tt> is | |
| 191 | + * <tt>CompositeData</tt> with attributes as specified in the | |
| 192 | + * {@link ThreadInfo#from ThreadInfo.from} method. | |
| 193 | + * | |
| 194 | + * @param id the thread ID of the thread. Must be positive. | |
| 195 | + * | |
| 196 | + * @return a {@link ThreadInfo} object for the thread of the given ID | |
| 197 | + * with no stack trace, no locked monitor and no synchronizer info; | |
| 198 | + * <tt>null</tt> if the thread of the given ID is not alive or | |
| 199 | + * it does not exist. | |
| 200 | + * | |
| 201 | + * @throws IllegalArgumentException if <tt>id <= 0</tt>. | |
| 202 | + * @throws java.lang.SecurityException if a security manager | |
| 203 | + * exists and the caller does not have | |
| 204 | + * ManagementPermission("monitor"). | |
| 205 | + */ | |
| 206 | + public ThreadInfo getThreadInfo(long id); | |
| 207 | + | |
| 208 | + /** | |
| 209 | + * Returns the thread info for each thread | |
| 210 | + * whose ID is in the input array <tt>ids</tt> with no stack trace. | |
| 211 | + * This method is equivalent to calling: | |
| 212 | + * <blockquote><pre> | |
| 213 | + * {@link #getThreadInfo(long[], int) getThreadInfo}(ids, 0); | |
| 214 | + * </pre></blockquote> | |
| 215 | + * | |
| 216 | + * <p> | |
| 217 | + * This method returns an array of the <tt>ThreadInfo</tt> objects. | |
| 218 | + * The stack trace, locked monitors, and locked synchronizers | |
| 219 | + * in each <tt>ThreadInfo</tt> object will be empty. | |
| 220 | + * | |
| 221 | + * If a thread of a given ID is not alive or does not exist, | |
| 222 | + * the corresponding element in the returned array will | |
| 223 | + * contain <tt>null</tt>. A thread is alive if | |
| 224 | + * it has been started and has not yet died. | |
| 225 | + * | |
| 226 | + * <p> | |
| 227 | + * <b>MBeanServer access</b>:<br> | |
| 228 | + * The mapped type of <tt>ThreadInfo</tt> is | |
| 229 | + * <tt>CompositeData</tt> with attributes as specified in the | |
| 230 | + * {@link ThreadInfo#from ThreadInfo.from} method. | |
| 231 | + * | |
| 232 | + * @param ids an array of thread IDs. | |
| 233 | + * @return an array of the {@link ThreadInfo} objects, each containing | |
| 234 | + * information about a thread whose ID is in the corresponding | |
| 235 | + * element of the input array of IDs | |
| 236 | + * with no stack trace, no locked monitor and no synchronizer info. | |
| 237 | + * | |
| 238 | + * @throws IllegalArgumentException if any element in the input array | |
| 239 | + * <tt>ids</tt> is <tt><= 0</tt>. | |
| 240 | + * @throws java.lang.SecurityException if a security manager | |
| 241 | + * exists and the caller does not have | |
| 242 | + * ManagementPermission("monitor"). | |
| 243 | + */ | |
| 244 | + public ThreadInfo[] getThreadInfo(long[] ids); | |
| 245 | + | |
| 246 | + /** | |
| 247 | + * Returns a thread info for a thread of the specified <tt>id</tt>, | |
| 248 | + * with stack trace of a specified number of stack trace elements. | |
| 249 | + * The <tt>maxDepth</tt> parameter indicates the maximum number of | |
| 250 | + * {@link StackTraceElement} to be retrieved from the stack trace. | |
| 251 | + * If <tt>maxDepth == Integer.MAX_VALUE</tt>, the entire stack trace of | |
| 252 | + * the thread will be dumped. | |
| 253 | + * If <tt>maxDepth == 0</tt>, no stack trace of the thread | |
| 254 | + * will be dumped. | |
| 255 | + * This method does not obtain the locked monitors and locked | |
| 256 | + * synchronizers of the thread. | |
| 257 | + * <p> | |
| 258 | + * When the Java virtual machine has no stack trace information | |
| 259 | + * about a thread or <tt>maxDepth == 0</tt>, | |
| 260 | + * the stack trace in the | |
| 261 | + * <tt>ThreadInfo</tt> object will be an empty array of | |
| 262 | + * <tt>StackTraceElement</tt>. | |
| 263 | + * | |
| 264 | + * <p> | |
| 265 | + * If a thread of the given ID is not alive or does not exist, | |
| 266 | + * this method will return <tt>null</tt>. A thread is alive if | |
| 267 | + * it has been started and has not yet died. | |
| 268 | + * | |
| 269 | + * <p> | |
| 270 | + * <b>MBeanServer access</b>:<br> | |
| 271 | + * The mapped type of <tt>ThreadInfo</tt> is | |
| 272 | + * <tt>CompositeData</tt> with attributes as specified in the | |
| 273 | + * {@link ThreadInfo#from ThreadInfo.from} method. | |
| 274 | + * | |
| 275 | + * @param id the thread ID of the thread. Must be positive. | |
| 276 | + * @param maxDepth the maximum number of entries in the stack trace | |
| 277 | + * to be dumped. <tt>Integer.MAX_VALUE</tt> could be used to request | |
| 278 | + * the entire stack to be dumped. | |
| 279 | + * | |
| 280 | + * @return a {@link ThreadInfo} of the thread of the given ID | |
| 281 | + * with no locked monitor and synchronizer info. | |
| 282 | + * <tt>null</tt> if the thread of the given ID is not alive or | |
| 283 | + * it does not exist. | |
| 284 | + * | |
| 285 | + * @throws IllegalArgumentException if <tt>id <= 0</tt>. | |
| 286 | + * @throws IllegalArgumentException if <tt>maxDepth is negative</tt>. | |
| 287 | + * @throws java.lang.SecurityException if a security manager | |
| 288 | + * exists and the caller does not have | |
| 289 | + * ManagementPermission("monitor"). | |
| 290 | + * | |
| 291 | + */ | |
| 292 | + public ThreadInfo getThreadInfo(long id, int maxDepth); | |
| 293 | + | |
| 294 | + /** | |
| 295 | + * Returns the thread info for each thread | |
| 296 | + * whose ID is in the input array <tt>ids</tt>, | |
| 297 | + * with stack trace of a specified number of stack trace elements. | |
| 298 | + * The <tt>maxDepth</tt> parameter indicates the maximum number of | |
| 299 | + * {@link StackTraceElement} to be retrieved from the stack trace. | |
| 300 | + * If <tt>maxDepth == Integer.MAX_VALUE</tt>, the entire stack trace of | |
| 301 | + * the thread will be dumped. | |
| 302 | + * If <tt>maxDepth == 0</tt>, no stack trace of the thread | |
| 303 | + * will be dumped. | |
| 304 | + * This method does not obtain the locked monitors and locked | |
| 305 | + * synchronizers of the threads. | |
| 306 | + * <p> | |
| 307 | + * When the Java virtual machine has no stack trace information | |
| 308 | + * about a thread or <tt>maxDepth == 0</tt>, | |
| 309 | + * the stack trace in the | |
| 310 | + * <tt>ThreadInfo</tt> object will be an empty array of | |
| 311 | + * <tt>StackTraceElement</tt>. | |
| 312 | + * <p> | |
| 313 | + * This method returns an array of the <tt>ThreadInfo</tt> objects, | |
| 314 | + * each is the thread information about the thread with the same index | |
| 315 | + * as in the <tt>ids</tt> array. | |
| 316 | + * If a thread of the given ID is not alive or does not exist, | |
| 317 | + * <tt>null</tt> will be set in the corresponding element | |
| 318 | + * in the returned array. A thread is alive if | |
| 319 | + * it has been started and has not yet died. | |
| 320 | + * | |
| 321 | + * <p> | |
| 322 | + * <b>MBeanServer access</b>:<br> | |
| 323 | + * The mapped type of <tt>ThreadInfo</tt> is | |
| 324 | + * <tt>CompositeData</tt> with attributes as specified in the | |
| 325 | + * {@link ThreadInfo#from ThreadInfo.from} method. | |
| 326 | + * | |
| 327 | + * @param ids an array of thread IDs | |
| 328 | + * @param maxDepth the maximum number of entries in the stack trace | |
| 329 | + * to be dumped. <tt>Integer.MAX_VALUE</tt> could be used to request | |
| 330 | + * the entire stack to be dumped. | |
| 331 | + * | |
| 332 | + * @return an array of the {@link ThreadInfo} objects, each containing | |
| 333 | + * information about a thread whose ID is in the corresponding | |
| 334 | + * element of the input array of IDs with no locked monitor and | |
| 335 | + * synchronizer info. | |
| 336 | + * | |
| 337 | + * @throws IllegalArgumentException if <tt>maxDepth is negative</tt>. | |
| 338 | + * @throws IllegalArgumentException if any element in the input array | |
| 339 | + * <tt>ids</tt> is <tt><= 0</tt>. | |
| 340 | + * @throws java.lang.SecurityException if a security manager | |
| 341 | + * exists and the caller does not have | |
| 342 | + * ManagementPermission("monitor"). | |
| 343 | + * | |
| 344 | + */ | |
| 345 | + public ThreadInfo[] getThreadInfo(long[] ids, int maxDepth); | |
| 346 | + | |
| 347 | + /** | |
| 348 | + * Tests if the Java virtual machine supports thread contention monitoring. | |
| 349 | + * | |
| 350 | + * @return | |
| 351 | + * <tt>true</tt> | |
| 352 | + * if the Java virtual machine supports thread contention monitoring; | |
| 353 | + * <tt>false</tt> otherwise. | |
| 354 | + */ | |
| 355 | + public boolean isThreadContentionMonitoringSupported(); | |
| 356 | + | |
| 357 | + /** | |
| 358 | + * Tests if thread contention monitoring is enabled. | |
| 359 | + * | |
| 360 | + * @return <tt>true</tt> if thread contention monitoring is enabled; | |
| 361 | + * <tt>false</tt> otherwise. | |
| 362 | + * | |
| 363 | + * @throws java.lang.UnsupportedOperationException if the Java virtual | |
| 364 | + * machine does not support thread contention monitoring. | |
| 365 | + * | |
| 366 | + * @see #isThreadContentionMonitoringSupported | |
| 367 | + */ | |
| 368 | + public boolean isThreadContentionMonitoringEnabled(); | |
| 369 | + | |
| 370 | + /** | |
| 371 | + * Enables or disables thread contention monitoring. | |
| 372 | + * Thread contention monitoring is disabled by default. | |
| 373 | + * | |
| 374 | + * @param enable <tt>true</tt> to enable; | |
| 375 | + * <tt>false</tt> to disable. | |
| 376 | + * | |
| 377 | + * @throws java.lang.UnsupportedOperationException if the Java | |
| 378 | + * virtual machine does not support thread contention monitoring. | |
| 379 | + * | |
| 380 | + * @throws java.lang.SecurityException if a security manager | |
| 381 | + * exists and the caller does not have | |
| 382 | + * ManagementPermission("control"). | |
| 383 | + * | |
| 384 | + * @see #isThreadContentionMonitoringSupported | |
| 385 | + */ | |
| 386 | + public void setThreadContentionMonitoringEnabled(boolean enable); | |
| 387 | + | |
| 388 | + /** | |
| 389 | + * Returns the total CPU time for the current thread in nanoseconds. | |
| 390 | + * The returned value is of nanoseconds precision but | |
| 391 | + * not necessarily nanoseconds accuracy. | |
| 392 | + * If the implementation distinguishes between user mode time and system | |
| 393 | + * mode time, the returned CPU time is the amount of time that | |
| 394 | + * the current thread has executed in user mode or system mode. | |
| 395 | + * | |
| 396 | + * <p> | |
| 397 | + * This is a convenient method for local management use and is | |
| 398 | + * equivalent to calling: | |
| 399 | + * <blockquote><pre> | |
| 400 | + * {@link #getThreadCpuTime getThreadCpuTime}(Thread.currentThread().getId()); | |
| 401 | + * </pre></blockquote> | |
| 402 | + * | |
| 403 | + * @return the total CPU time for the current thread if CPU time | |
| 404 | + * measurement is enabled; <tt>-1</tt> otherwise. | |
| 405 | + * | |
| 406 | + * @throws java.lang.UnsupportedOperationException if the Java | |
| 407 | + * virtual machine does not support CPU time measurement for | |
| 408 | + * the current thread. | |
| 409 | + * | |
| 410 | + * @see #getCurrentThreadUserTime | |
| 411 | + * @see #isCurrentThreadCpuTimeSupported | |
| 412 | + * @see #isThreadCpuTimeEnabled | |
| 413 | + * @see #setThreadCpuTimeEnabled | |
| 414 | + */ | |
| 415 | + public long getCurrentThreadCpuTime(); | |
| 416 | + | |
| 417 | + /** | |
| 418 | + * Returns the CPU time that the current thread has executed | |
| 419 | + * in user mode in nanoseconds. | |
| 420 | + * The returned value is of nanoseconds precision but | |
| 421 | + * not necessarily nanoseconds accuracy. | |
| 422 | + * | |
| 423 | + * <p> | |
| 424 | + * This is a convenient method for local management use and is | |
| 425 | + * equivalent to calling: | |
| 426 | + * <blockquote><pre> | |
| 427 | + * {@link #getThreadUserTime getThreadUserTime}(Thread.currentThread().getId()); | |
| 428 | + * </pre></blockquote> | |
| 429 | + * | |
| 430 | + * @return the user-level CPU time for the current thread if CPU time | |
| 431 | + * measurement is enabled; <tt>-1</tt> otherwise. | |
| 432 | + * | |
| 433 | + * @throws java.lang.UnsupportedOperationException if the Java | |
| 434 | + * virtual machine does not support CPU time measurement for | |
| 435 | + * the current thread. | |
| 436 | + * | |
| 437 | + * @see #getCurrentThreadCpuTime | |
| 438 | + * @see #isCurrentThreadCpuTimeSupported | |
| 439 | + * @see #isThreadCpuTimeEnabled | |
| 440 | + * @see #setThreadCpuTimeEnabled | |
| 441 | + */ | |
| 442 | + public long getCurrentThreadUserTime(); | |
| 443 | + | |
| 444 | + /** | |
| 445 | + * Returns the total CPU time for a thread of the specified ID in nanoseconds. | |
| 446 | + * The returned value is of nanoseconds precision but | |
| 447 | + * not necessarily nanoseconds accuracy. | |
| 448 | + * If the implementation distinguishes between user mode time and system | |
| 449 | + * mode time, the returned CPU time is the amount of time that | |
| 450 | + * the thread has executed in user mode or system mode. | |
| 451 | + * | |
| 452 | + * <p> | |
| 453 | + * If the thread of the specified ID is not alive or does not exist, | |
| 454 | + * this method returns <tt>-1</tt>. If CPU time measurement | |
| 455 | + * is disabled, this method returns <tt>-1</tt>. | |
| 456 | + * A thread is alive if it has been started and has not yet died. | |
| 457 | + * <p> | |
| 458 | + * If CPU time measurement is enabled after the thread has started, | |
| 459 | + * the Java virtual machine implementation may choose any time up to | |
| 460 | + * and including the time that the capability is enabled as the point | |
| 461 | + * where CPU time measurement starts. | |
| 462 | + * | |
| 463 | + * @param id the thread ID of a thread | |
| 464 | + * @return the total CPU time for a thread of the specified ID | |
| 465 | + * if the thread of the specified ID exists, the thread is alive, | |
| 466 | + * and CPU time measurement is enabled; | |
| 467 | + * <tt>-1</tt> otherwise. | |
| 468 | + * | |
| 469 | + * @throws IllegalArgumentException if <tt>id <= 0 </tt>. | |
| 470 | + * @throws java.lang.UnsupportedOperationException if the Java | |
| 471 | + * virtual machine does not support CPU time measurement for | |
| 472 | + * other threads. | |
| 473 | + * | |
| 474 | + * @see #getThreadUserTime | |
| 475 | + * @see #isThreadCpuTimeSupported | |
| 476 | + * @see #isThreadCpuTimeEnabled | |
| 477 | + * @see #setThreadCpuTimeEnabled | |
| 478 | + */ | |
| 479 | + public long getThreadCpuTime(long id); | |
| 480 | + | |
| 481 | + /** | |
| 482 | + * Returns the CPU time that a thread of the specified ID | |
| 483 | + * has executed in user mode in nanoseconds. | |
| 484 | + * The returned value is of nanoseconds precision but | |
| 485 | + * not necessarily nanoseconds accuracy. | |
| 486 | + * | |
| 487 | + * <p> | |
| 488 | + * If the thread of the specified ID is not alive or does not exist, | |
| 489 | + * this method returns <tt>-1</tt>. If CPU time measurement | |
| 490 | + * is disabled, this method returns <tt>-1</tt>. | |
| 491 | + * A thread is alive if it has been started and has not yet died. | |
| 492 | + * <p> | |
| 493 | + * If CPU time measurement is enabled after the thread has started, | |
| 494 | + * the Java virtual machine implementation may choose any time up to | |
| 495 | + * and including the time that the capability is enabled as the point | |
| 496 | + * where CPU time measurement starts. | |
| 497 | + * | |
| 498 | + * @param id the thread ID of a thread | |
| 499 | + * @return the user-level CPU time for a thread of the specified ID | |
| 500 | + * if the thread of the specified ID exists, the thread is alive, | |
| 501 | + * and CPU time measurement is enabled; | |
| 502 | + * <tt>-1</tt> otherwise. | |
| 503 | + * | |
| 504 | + * @throws IllegalArgumentException if <tt>id <= 0 </tt>. | |
| 505 | + * @throws java.lang.UnsupportedOperationException if the Java | |
| 506 | + * virtual machine does not support CPU time measurement for | |
| 507 | + * other threads. | |
| 508 | + * | |
| 509 | + * @see #getThreadCpuTime | |
| 510 | + * @see #isThreadCpuTimeSupported | |
| 511 | + * @see #isThreadCpuTimeEnabled | |
| 512 | + * @see #setThreadCpuTimeEnabled | |
| 513 | + */ | |
| 514 | + public long getThreadUserTime(long id); | |
| 515 | + | |
| 516 | + /** | |
| 517 | + * Tests if the Java virtual machine implementation supports CPU time | |
| 518 | + * measurement for any thread. | |
| 519 | + * A Java virtual machine implementation that supports CPU time | |
| 520 | + * measurement for any thread will also support CPU time | |
| 521 | + * measurement for the current thread. | |
| 522 | + * | |
| 523 | + * @return | |
| 524 | + * <tt>true</tt> | |
| 525 | + * if the Java virtual machine supports CPU time | |
| 526 | + * measurement for any thread; | |
| 527 | + * <tt>false</tt> otherwise. | |
| 528 | + */ | |
| 529 | + public boolean isThreadCpuTimeSupported(); | |
| 530 | + | |
| 531 | + /** | |
| 532 | + * Tests if the Java virtual machine supports CPU time | |
| 533 | + * measurement for the current thread. | |
| 534 | + * This method returns <tt>true</tt> if {@link #isThreadCpuTimeSupported} | |
| 535 | + * returns <tt>true</tt>. | |
| 536 | + * | |
| 537 | + * @return | |
| 538 | + * <tt>true</tt> | |
| 539 | + * if the Java virtual machine supports CPU time | |
| 540 | + * measurement for current thread; | |
| 541 | + * <tt>false</tt> otherwise. | |
| 542 | + */ | |
| 543 | + public boolean isCurrentThreadCpuTimeSupported(); | |
| 544 | + | |
| 545 | + /** | |
| 546 | + * Tests if thread CPU time measurement is enabled. | |
| 547 | + * | |
| 548 | + * @return <tt>true</tt> if thread CPU time measurement is enabled; | |
| 549 | + * <tt>false</tt> otherwise. | |
| 550 | + * | |
| 551 | + * @throws java.lang.UnsupportedOperationException if the Java virtual | |
| 552 | + * machine does not support CPU time measurement for other threads | |
| 553 | + * nor for the current thread. | |
| 554 | + * | |
| 555 | + * @see #isThreadCpuTimeSupported | |
| 556 | + * @see #isCurrentThreadCpuTimeSupported | |
| 557 | + */ | |
| 558 | + public boolean isThreadCpuTimeEnabled(); | |
| 559 | + | |
| 560 | + /** | |
| 561 | + * Enables or disables thread CPU time measurement. The default | |
| 562 | + * is platform dependent. | |
| 563 | + * | |
| 564 | + * @param enable <tt>true</tt> to enable; | |
| 565 | + * <tt>false</tt> to disable. | |
| 566 | + * | |
| 567 | + * @throws java.lang.UnsupportedOperationException if the Java | |
| 568 | + * virtual machine does not support CPU time measurement for | |
| 569 | + * any threads nor for the current thread. | |
| 570 | + * | |
| 571 | + * @throws java.lang.SecurityException if a security manager | |
| 572 | + * exists and the caller does not have | |
| 573 | + * ManagementPermission("control"). | |
| 574 | + * | |
| 575 | + * @see #isThreadCpuTimeSupported | |
| 576 | + * @see #isCurrentThreadCpuTimeSupported | |
| 577 | + */ | |
| 578 | + public void setThreadCpuTimeEnabled(boolean enable); | |
| 579 | + | |
| 580 | + /** | |
| 581 | + * Finds cycles of threads that are in deadlock waiting to acquire | |
| 582 | + * object monitors. That is, threads that are blocked waiting to enter a | |
| 583 | + * synchronization block or waiting to reenter a synchronization block | |
| 584 | + * after an {@link Object#wait Object.wait} call, | |
| 585 | + * where each thread owns one monitor while | |
| 586 | + * trying to obtain another monitor already held by another thread | |
| 587 | + * in a cycle. | |
| 588 | + * <p> | |
| 589 | + * More formally, a thread is <em>monitor deadlocked</em> if it is | |
| 590 | + * part of a cycle in the relation "is waiting for an object monitor | |
| 591 | + * owned by". In the simplest case, thread A is blocked waiting | |
| 592 | + * for a monitor owned by thread B, and thread B is blocked waiting | |
| 593 | + * for a monitor owned by thread A. | |
| 594 | + * <p> | |
| 595 | + * This method is designed for troubleshooting use, but not for | |
| 596 | + * synchronization control. It might be an expensive operation. | |
| 597 | + * <p> | |
| 598 | + * This method finds deadlocks involving only object monitors. | |
| 599 | + * To find deadlocks involving both object monitors and | |
| 600 | + * <a href="LockInfo.html#OwnableSynchronizer">ownable synchronizers</a>, | |
| 601 | + * the {@link #findDeadlockedThreads findDeadlockedThreads} method | |
| 602 | + * should be used. | |
| 603 | + * | |
| 604 | + * @return an array of IDs of the threads that are monitor | |
| 605 | + * deadlocked, if any; <tt>null</tt> otherwise. | |
| 606 | + * | |
| 607 | + * @throws java.lang.SecurityException if a security manager | |
| 608 | + * exists and the caller does not have | |
| 609 | + * ManagementPermission("monitor"). | |
| 610 | + * | |
| 611 | + * @see #findDeadlockedThreads | |
| 612 | + */ | |
| 613 | + public long[] findMonitorDeadlockedThreads(); | |
| 614 | + | |
| 615 | + /** | |
| 616 | + * Resets the peak thread count to the current number of | |
| 617 | + * live threads. | |
| 618 | + * | |
| 619 | + * @throws java.lang.SecurityException if a security manager | |
| 620 | + * exists and the caller does not have | |
| 621 | + * ManagementPermission("control"). | |
| 622 | + * | |
| 623 | + * @see #getPeakThreadCount | |
| 624 | + * @see #getThreadCount | |
| 625 | + */ | |
| 626 | + public void resetPeakThreadCount(); | |
| 627 | + | |
| 628 | + /** | |
| 629 | + * Finds cycles of threads that are in deadlock waiting to acquire | |
| 630 | + * object monitors or | |
| 631 | + * <a href="LockInfo.html#OwnableSynchronizer">ownable synchronizers</a>. | |
| 632 | + * | |
| 633 | + * Threads are <em>deadlocked</em> in a cycle waiting for a lock of | |
| 634 | + * these two types if each thread owns one lock while | |
| 635 | + * trying to acquire another lock already held | |
| 636 | + * by another thread in the cycle. | |
| 637 | + * <p> | |
| 638 | + * This method is designed for troubleshooting use, but not for | |
| 639 | + * synchronization control. It might be an expensive operation. | |
| 640 | + * | |
| 641 | + * @return an array of IDs of the threads that are | |
| 642 | + * deadlocked waiting for object monitors or ownable synchronizers, if any; | |
| 643 | + * <tt>null</tt> otherwise. | |
| 644 | + * | |
| 645 | + * @throws java.lang.SecurityException if a security manager | |
| 646 | + * exists and the caller does not have | |
| 647 | + * ManagementPermission("monitor"). | |
| 648 | + * @throws java.lang.UnsupportedOperationException if the Java virtual | |
| 649 | + * machine does not support monitoriing of ownable synchronizer usage. | |
| 650 | + * | |
| 651 | + * @see #isSynchronizerUsageSupported | |
| 652 | + * @see #findMonitorDeadlockedThreads | |
| 653 | + * @since 1.6 | |
| 654 | + */ | |
| 655 | + public long[] findDeadlockedThreads(); | |
| 656 | + | |
| 657 | + /** | |
| 658 | + * Tests if the Java virtual machine supports monitoring of | |
| 659 | + * object monitor usage. | |
| 660 | + * | |
| 661 | + * @return | |
| 662 | + * <tt>true</tt> | |
| 663 | + * if the Java virtual machine supports monitoring of | |
| 664 | + * object monitor usage; | |
| 665 | + * <tt>false</tt> otherwise. | |
| 666 | + * | |
| 667 | + * @see #dumpAllThreads | |
| 668 | + * @since 1.6 | |
| 669 | + */ | |
| 670 | + public boolean isObjectMonitorUsageSupported(); | |
| 671 | + | |
| 672 | + /** | |
| 673 | + * Tests if the Java virtual machine supports monitoring of | |
| 674 | + * <a href="LockInfo.html#OwnableSynchronizer"> | |
| 675 | + * ownable synchronizer</a> usage. | |
| 676 | + * | |
| 677 | + * @return | |
| 678 | + * <tt>true</tt> | |
| 679 | + * if the Java virtual machine supports monitoring of ownable | |
| 680 | + * synchronizer usage; | |
| 681 | + * <tt>false</tt> otherwise. | |
| 682 | + * | |
| 683 | + * @see #dumpAllThreads | |
| 684 | + * @since 1.6 | |
| 685 | + */ | |
| 686 | + public boolean isSynchronizerUsageSupported(); | |
| 687 | + | |
| 688 | + /** | |
| 689 | + * Returns the thread info for each thread | |
| 690 | + * whose ID is in the input array <tt>ids</tt>, with stack trace | |
| 691 | + * and synchronization information. | |
| 692 | + * | |
| 693 | + * <p> | |
| 694 | + * This method obtains a snapshot of the thread information | |
| 695 | + * for each thread including: | |
| 696 | + * <ul> | |
| 697 | + * <li>the entire stack trace,</li> | |
| 698 | + * <li>the object monitors currently locked by the thread | |
| 699 | + * if <tt>lockedMonitors</tt> is <tt>true</tt>, and</li> | |
| 700 | + * <li>the <a href="LockInfo.html#OwnableSynchronizer"> | |
| 701 | + * ownable synchronizers</a> currently locked by the thread | |
| 702 | + * if <tt>lockedSynchronizers</tt> is <tt>true</tt>.</li> | |
| 703 | + * </ul> | |
| 704 | + * <p> | |
| 705 | + * This method returns an array of the <tt>ThreadInfo</tt> objects, | |
| 706 | + * each is the thread information about the thread with the same index | |
| 707 | + * as in the <tt>ids</tt> array. | |
| 708 | + * If a thread of the given ID is not alive or does not exist, | |
| 709 | + * <tt>null</tt> will be set in the corresponding element | |
| 710 | + * in the returned array. A thread is alive if | |
| 711 | + * it has been started and has not yet died. | |
| 712 | + * <p> | |
| 713 | + * If a thread does not lock any object monitor or <tt>lockedMonitors</tt> | |
| 714 | + * is <tt>false</tt>, the returned <tt>ThreadInfo</tt> object will have an | |
| 715 | + * empty <tt>MonitorInfo</tt> array. Similarly, if a thread does not | |
| 716 | + * lock any synchronizer or <tt>lockedSynchronizers</tt> is <tt>false</tt>, | |
| 717 | + * the returned <tt>ThreadInfo</tt> object | |
| 718 | + * will have an empty <tt>LockInfo</tt> array. | |
| 719 | + * | |
| 720 | + * <p> | |
| 721 | + * When both <tt>lockedMonitors</tt> and <tt>lockedSynchronizers</tt> | |
| 722 | + * parameters are <tt>false</tt>, it is equivalent to calling: | |
| 723 | + * <blockquote><pre> | |
| 724 | + * {@link #getThreadInfo(long[], int) getThreadInfo(ids, Integer.MAX_VALUE)} | |
| 725 | + * </pre></blockquote> | |
| 726 | + * | |
| 727 | + * <p> | |
| 728 | + * This method is designed for troubleshooting use, but not for | |
| 729 | + * synchronization control. It might be an expensive operation. | |
| 730 | + * | |
| 731 | + * <p> | |
| 732 | + * <b>MBeanServer access</b>:<br> | |
| 733 | + * The mapped type of <tt>ThreadInfo</tt> is | |
| 734 | + * <tt>CompositeData</tt> with attributes as specified in the | |
| 735 | + * {@link ThreadInfo#from ThreadInfo.from} method. | |
| 736 | + * | |
| 737 | + * @param ids an array of thread IDs. | |
| 738 | + * @param lockedMonitors if <tt>true</tt>, retrieves all locked monitors. | |
| 739 | + * @param lockedSynchronizers if <tt>true</tt>, retrieves all locked | |
| 740 | + * ownable synchronizers. | |
| 741 | + * | |
| 742 | + * @return an array of the {@link ThreadInfo} objects, each containing | |
| 743 | + * information about a thread whose ID is in the corresponding | |
| 744 | + * element of the input array of IDs. | |
| 745 | + * | |
| 746 | + * @throws java.lang.SecurityException if a security manager | |
| 747 | + * exists and the caller does not have | |
| 748 | + * ManagementPermission("monitor"). | |
| 749 | + * @throws java.lang.UnsupportedOperationException | |
| 750 | + * <ul> | |
| 751 | + * <li>if <tt>lockedMonitors</tt> is <tt>true</tt> but | |
| 752 | + * the Java virtual machine does not support monitoring | |
| 753 | + * of {@linkplain #isObjectMonitorUsageSupported | |
| 754 | + * object monitor usage}; or</li> | |
| 755 | + * <li>if <tt>lockedSynchronizers</tt> is <tt>true</tt> but | |
| 756 | + * the Java virtual machine does not support monitoring | |
| 757 | + * of {@linkplain #isSynchronizerUsageSupported | |
| 758 | + * ownable synchronizer usage}.</li> | |
| 759 | + * </ul> | |
| 760 | + * | |
| 761 | + * @see #isObjectMonitorUsageSupported | |
| 762 | + * @see #isSynchronizerUsageSupported | |
| 763 | + * | |
| 764 | + * @since 1.6 | |
| 765 | + */ | |
| 766 | + public ThreadInfo[] getThreadInfo(long[] ids, boolean lockedMonitors, boolean lockedSynchronizers); | |
| 767 | + | |
| 768 | + /** | |
| 769 | + * Returns the thread info for all live threads with stack trace | |
| 770 | + * and synchronization information. | |
| 771 | + * Some threads included in the returned array | |
| 772 | + * may have been terminated when this method returns. | |
| 773 | + * | |
| 774 | + * <p> | |
| 775 | + * This method returns an array of {@link ThreadInfo} objects | |
| 776 | + * as specified in the {@link #getThreadInfo(long[], boolean, boolean)} | |
| 777 | + * method. | |
| 778 | + * | |
| 779 | + * @param lockedMonitors if <tt>true</tt>, dump all locked monitors. | |
| 780 | + * @param lockedSynchronizers if <tt>true</tt>, dump all locked | |
| 781 | + * ownable synchronizers. | |
| 782 | + * | |
| 783 | + * @return an array of {@link ThreadInfo} for all live threads. | |
| 784 | + * | |
| 785 | + * @throws java.lang.SecurityException if a security manager | |
| 786 | + * exists and the caller does not have | |
| 787 | + * ManagementPermission("monitor"). | |
| 788 | + * @throws java.lang.UnsupportedOperationException | |
| 789 | + * <ul> | |
| 790 | + * <li>if <tt>lockedMonitors</tt> is <tt>true</tt> but | |
| 791 | + * the Java virtual machine does not support monitoring | |
| 792 | + * of {@linkplain #isObjectMonitorUsageSupported | |
| 793 | + * object monitor usage}; or</li> | |
| 794 | + * <li>if <tt>lockedSynchronizers</tt> is <tt>true</tt> but | |
| 795 | + * the Java virtual machine does not support monitoring | |
| 796 | + * of {@linkplain #isSynchronizerUsageSupported | |
| 797 | + * ownable synchronizer usage}.</li> | |
| 798 | + * </ul> | |
| 799 | + * | |
| 800 | + * @see #isObjectMonitorUsageSupported | |
| 801 | + * @see #isSynchronizerUsageSupported | |
| 802 | + * | |
| 803 | + * @since 1.6 | |
| 804 | + */ | |
| 805 | + public ThreadInfo[] dumpAllThreads(boolean lockedMonitors, boolean lockedSynchronizers); | |
| 806 | +} | |