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src/java.base/share/classes/java/lang/ThreadBuilders.java

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 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 package java.lang;
 26 
 27 import java.lang.Thread.Builder.OfPlatform;
 28 import java.lang.Thread.Builder.OfVirtual;
 29 import java.lang.Thread.UncaughtExceptionHandler;
 30 import java.lang.invoke.MethodHandles;
 31 import java.lang.invoke.VarHandle;
 32 import java.util.Locale;
 33 import java.util.Objects;
 34 import java.util.concurrent.Executor;
 35 import java.util.concurrent.ThreadFactory;
 36 import jdk.internal.misc.Unsafe;
 37 import jdk.internal.invoke.MhUtil;
 38 import jdk.internal.vm.ContinuationSupport;
 39 
 40 /**
 41  * Defines static methods to create platform and virtual thread builders.
 42  */
 43 class ThreadBuilders {
 44     private ThreadBuilders() { }
 45 
 46     /**
 47      * Base class for Thread.Builder implementations.
 48      */
 49     private static class BaseThreadBuilder {
 50         private String name;
 51         private long counter;
 52         private int characteristics;
 53         private UncaughtExceptionHandler uhe;
 54 

185             if (priority != 0)
186                 thread.priority(priority);
187             UncaughtExceptionHandler uhe = uncaughtExceptionHandler();
188             if (uhe != null)
189                 thread.uncaughtExceptionHandler(uhe);
190             return thread;
191         }
192 
193         @Override
194         public Thread start(Runnable task) {
195             Thread thread = unstarted(task);
196             thread.start();
197             return thread;
198         }
199 
200         @Override
201         public ThreadFactory factory() {
202             return new PlatformThreadFactory(group, name(), counter(), characteristics(),
203                     daemonChanged, daemon, priority, stackSize, uncaughtExceptionHandler());
204         }
205 
206     }
207 
208     /**
209      * ThreadBuilder.OfVirtual implementation.
210      */
211     static final class VirtualThreadBuilder
212             extends BaseThreadBuilder implements OfVirtual {
213         private Executor scheduler;
214 
215         VirtualThreadBuilder() {
216         }
217 
218         // invoked by tests
219         VirtualThreadBuilder(Executor scheduler) {
220             if (!ContinuationSupport.isSupported())
221                 throw new UnsupportedOperationException();
222             this.scheduler = Objects.requireNonNull(scheduler);
223         }
224 
225         @Override
226         public OfVirtual name(String name) {
227             setName(name);
228             return this;
229         }
230 
231         @Override
232         public OfVirtual name(String prefix, long start) {
233             setName(prefix, start);
234             return this;
235         }
236 
237         @Override
238         public OfVirtual inheritInheritableThreadLocals(boolean inherit) {
239             setInheritInheritableThreadLocals(inherit);
240             return this;
241         }
242 
243         @Override
244         public OfVirtual uncaughtExceptionHandler(UncaughtExceptionHandler ueh) {
245             setUncaughtExceptionHandler(ueh);
246             return this;
247         }
248 
249         @Override
250         public Thread unstarted(Runnable task) {
251             Objects.requireNonNull(task);
252             var thread = newVirtualThread(scheduler, nextThreadName(), characteristics(), task);




253             UncaughtExceptionHandler uhe = uncaughtExceptionHandler();
254             if (uhe != null)
255                 thread.uncaughtExceptionHandler(uhe);
256             return thread;
257         }
258 





259         @Override
260         public Thread start(Runnable task) {
261             Thread thread = unstarted(task);
262             thread.start();
263             return thread;
264         }
265 
266         @Override
267         public ThreadFactory factory() {
268             return new VirtualThreadFactory(scheduler, name(), counter(), characteristics(),
269                     uncaughtExceptionHandler());
270         }
271     }
272 
273     /**
274      * Base ThreadFactory implementation.
275      */
276     private abstract static class BaseThreadFactory implements ThreadFactory {
277         private static final VarHandle COUNT = MhUtil.findVarHandle(
278                 MethodHandles.lookup(), "count", long.class);

352         @Override
353         public Thread newThread(Runnable task) {
354             Objects.requireNonNull(task);
355             String name = nextThreadName();
356             Thread thread = new Thread(group, name, characteristics(), task, stackSize);
357             if (daemonChanged)
358                 thread.daemon(daemon);
359             if (priority != 0)
360                 thread.priority(priority);
361             UncaughtExceptionHandler uhe = uncaughtExceptionHandler();
362             if (uhe != null)
363                 thread.uncaughtExceptionHandler(uhe);
364             return thread;
365         }
366     }
367 
368     /**
369      * ThreadFactory for virtual threads.
370      */
371     private static class VirtualThreadFactory extends BaseThreadFactory {
372         private final Executor scheduler;
373 
374         VirtualThreadFactory(Executor scheduler,
375                              String name,
376                              long start,
377                              int characteristics,
378                              UncaughtExceptionHandler uhe) {
379             super(name, start, characteristics, uhe);
380             this.scheduler = scheduler;
381         }
382 
383         @Override
384         public Thread newThread(Runnable task) {
385             Objects.requireNonNull(task);
386             String name = nextThreadName();
387             Thread thread = newVirtualThread(scheduler, name, characteristics(), task);
388             UncaughtExceptionHandler uhe = uncaughtExceptionHandler();
389             if (uhe != null)
390                 thread.uncaughtExceptionHandler(uhe);
391             return thread;
392         }
393     }
394 
395     /**
396      * Creates a new virtual thread to run the given task.
397      */
398     static Thread newVirtualThread(Executor scheduler,
399                                    String name,
400                                    int characteristics,
401                                    Runnable task) {

402         if (ContinuationSupport.isSupported()) {
403             return new VirtualThread(scheduler, name, characteristics, task);
404         } else {
405             if (scheduler != null)
406                 throw new UnsupportedOperationException();
407             return new BoundVirtualThread(name, characteristics, task);
408         }
409     }
410 




411     /**
412      * A "virtual thread" that is backed by a platform thread. This implementation
413      * is intended for platforms that don't have the underlying VM support for
414      * continuations. It can also be used for testing.
415      */
416     static final class BoundVirtualThread extends BaseVirtualThread {
417         private static final Unsafe U = Unsafe.getUnsafe();
418         private final Runnable task;
419         private boolean runInvoked;
420 
421         BoundVirtualThread(String name, int characteristics, Runnable task) {
422             super(name, characteristics, true);
423             this.task = task;
424         }
425 
426         @Override
427         public void run() {
428             // run is specified to do nothing when Thread is a virtual thread
429             if (Thread.currentThread() == this && !runInvoked) {
430                 runInvoked = true;

 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 package java.lang;
 26 
 27 import java.lang.Thread.Builder.OfPlatform;
 28 import java.lang.Thread.Builder.OfVirtual;
 29 import java.lang.Thread.UncaughtExceptionHandler;
 30 import java.lang.invoke.MethodHandles;
 31 import java.lang.invoke.VarHandle;
 32 import java.util.Locale;
 33 import java.util.Objects;

 34 import java.util.concurrent.ThreadFactory;
 35 import jdk.internal.misc.Unsafe;
 36 import jdk.internal.invoke.MhUtil;
 37 import jdk.internal.vm.ContinuationSupport;
 38 
 39 /**
 40  * Defines static methods to create platform and virtual thread builders.
 41  */
 42 class ThreadBuilders {
 43     private ThreadBuilders() { }
 44 
 45     /**
 46      * Base class for Thread.Builder implementations.
 47      */
 48     private static class BaseThreadBuilder {
 49         private String name;
 50         private long counter;
 51         private int characteristics;
 52         private UncaughtExceptionHandler uhe;
 53 

184             if (priority != 0)
185                 thread.priority(priority);
186             UncaughtExceptionHandler uhe = uncaughtExceptionHandler();
187             if (uhe != null)
188                 thread.uncaughtExceptionHandler(uhe);
189             return thread;
190         }
191 
192         @Override
193         public Thread start(Runnable task) {
194             Thread thread = unstarted(task);
195             thread.start();
196             return thread;
197         }
198 
199         @Override
200         public ThreadFactory factory() {
201             return new PlatformThreadFactory(group, name(), counter(), characteristics(),
202                     daemonChanged, daemon, priority, stackSize, uncaughtExceptionHandler());
203         }

204     }
205 
206     /**
207      * ThreadBuilder.OfVirtual implementation.
208      */
209     static final class VirtualThreadBuilder
210             extends BaseThreadBuilder implements OfVirtual {
211         private Thread.VirtualThreadScheduler scheduler;
212 
213         VirtualThreadBuilder() {
214         }
215 







216         @Override
217         public OfVirtual name(String name) {
218             setName(name);
219             return this;
220         }
221 
222         @Override
223         public OfVirtual name(String prefix, long start) {
224             setName(prefix, start);
225             return this;
226         }
227 
228         @Override
229         public OfVirtual inheritInheritableThreadLocals(boolean inherit) {
230             setInheritInheritableThreadLocals(inherit);
231             return this;
232         }
233 
234         @Override
235         public OfVirtual uncaughtExceptionHandler(UncaughtExceptionHandler ueh) {
236             setUncaughtExceptionHandler(ueh);
237             return this;
238         }
239 
240         Thread unstarted(Runnable task, Thread preferredCarrier) {

241             Objects.requireNonNull(task);
242             var thread = newVirtualThread(scheduler,
243                                           preferredCarrier,
244                                           nextThreadName(),
245                                           characteristics(),
246                                           task);
247             UncaughtExceptionHandler uhe = uncaughtExceptionHandler();
248             if (uhe != null)
249                 thread.uncaughtExceptionHandler(uhe);
250             return thread;
251         }
252 
253         @Override
254         public Thread unstarted(Runnable task) {
255             return unstarted(task, null);
256         }
257 
258         @Override
259         public Thread start(Runnable task) {
260             Thread thread = unstarted(task);
261             thread.start();
262             return thread;
263         }
264 
265         @Override
266         public ThreadFactory factory() {
267             return new VirtualThreadFactory(scheduler, name(), counter(), characteristics(),
268                     uncaughtExceptionHandler());
269         }
270     }
271 
272     /**
273      * Base ThreadFactory implementation.
274      */
275     private abstract static class BaseThreadFactory implements ThreadFactory {
276         private static final VarHandle COUNT = MhUtil.findVarHandle(
277                 MethodHandles.lookup(), "count", long.class);

351         @Override
352         public Thread newThread(Runnable task) {
353             Objects.requireNonNull(task);
354             String name = nextThreadName();
355             Thread thread = new Thread(group, name, characteristics(), task, stackSize);
356             if (daemonChanged)
357                 thread.daemon(daemon);
358             if (priority != 0)
359                 thread.priority(priority);
360             UncaughtExceptionHandler uhe = uncaughtExceptionHandler();
361             if (uhe != null)
362                 thread.uncaughtExceptionHandler(uhe);
363             return thread;
364         }
365     }
366 
367     /**
368      * ThreadFactory for virtual threads.
369      */
370     private static class VirtualThreadFactory extends BaseThreadFactory {
371         private final Thread.VirtualThreadScheduler scheduler;
372 
373         VirtualThreadFactory(Thread.VirtualThreadScheduler scheduler,
374                              String name,
375                              long start,
376                              int characteristics,
377                              UncaughtExceptionHandler uhe) {
378             super(name, start, characteristics, uhe);
379             this.scheduler = scheduler;
380         }
381 
382         @Override
383         public Thread newThread(Runnable task) {
384             Objects.requireNonNull(task);
385             String name = nextThreadName();
386             Thread thread = newVirtualThread(scheduler, null, name, characteristics(), task);
387             UncaughtExceptionHandler uhe = uncaughtExceptionHandler();
388             if (uhe != null)
389                 thread.uncaughtExceptionHandler(uhe);
390             return thread;
391         }
392     }
393 
394     /**
395      * Creates a new virtual thread to run the given task.
396      */
397     private static Thread newVirtualThread(Thread.VirtualThreadScheduler scheduler,
398                                            Thread preferredCarrier,
399                                            String name,
400                                            int characteristics,
401                                            Runnable task) {
402         if (ContinuationSupport.isSupported()) {
403             return new VirtualThread(scheduler, preferredCarrier, name, characteristics, task);
404         } else {
405             if (scheduler != null)
406                 throw new UnsupportedOperationException();
407             return new BoundVirtualThread(name, characteristics, task);
408         }
409     }
410 
411     static Thread newVirtualThread(String name, int characteristics, Runnable task) {
412        return newVirtualThread(null, null, name, characteristics, task);
413     }
414 
415     /**
416      * A "virtual thread" that is backed by a platform thread. This implementation
417      * is intended for platforms that don't have the underlying VM support for
418      * continuations. It can also be used for testing.
419      */
420     static final class BoundVirtualThread extends BaseVirtualThread {
421         private static final Unsafe U = Unsafe.getUnsafe();
422         private final Runnable task;
423         private boolean runInvoked;
424 
425         BoundVirtualThread(String name, int characteristics, Runnable task) {
426             super(name, characteristics, true);
427             this.task = task;
428         }
429 
430         @Override
431         public void run() {
432             // run is specified to do nothing when Thread is a virtual thread
433             if (Thread.currentThread() == this && !runInvoked) {
434                 runInvoked = true;
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