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test/jdk/java/lang/Thread/virtual/CustomScheduler.java

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 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.
 22  */
 23 
 24 /**
 25  * @test
 26  * @summary Test virtual threads using a custom scheduler
 27  * @requires vm.continuations
 28  * @modules java.base/java.lang:+open
 29  * @library /test/lib
 30  * @run junit CustomScheduler
 31  */
 32 
 33 import java.lang.reflect.Field;
 34 import java.time.Duration;
 35 import java.util.ArrayList;
 36 import java.util.List;
 37 import java.util.concurrent.*;


 38 import java.util.concurrent.atomic.AtomicBoolean;
 39 import java.util.concurrent.atomic.AtomicInteger;
 40 import java.util.concurrent.atomic.AtomicReference;
 41 import java.util.concurrent.locks.LockSupport;
 42 
 43 import jdk.test.lib.thread.VThreadScheduler;
 44 import jdk.test.lib.thread.VThreadRunner;

 45 import org.junit.jupiter.api.Test;
 46 import org.junit.jupiter.api.BeforeAll;
 47 import org.junit.jupiter.api.AfterAll;
 48 import static org.junit.jupiter.api.Assertions.*;
 49 import static org.junit.jupiter.api.Assumptions.*;
 50 
 51 class CustomScheduler {
 52     private static ExecutorService scheduler1;
 53     private static ExecutorService scheduler2;

 54 
 55     @BeforeAll
 56     static void setup() {
 57         scheduler1 = Executors.newFixedThreadPool(1);
 58         scheduler2 = Executors.newFixedThreadPool(1);









 59     }
 60 
 61     @AfterAll
 62     static void shutdown() {
 63         scheduler1.shutdown();
 64         scheduler2.shutdown();
 65     }
 66 
 67     /**
 68      * Test platform thread creating a virtual thread that uses a custom scheduler.
 69      */
 70     @Test
 71     void testCustomScheduler1() throws Exception {
 72         var ref = new AtomicReference<Executor>();
 73         ThreadFactory factory = VThreadScheduler.virtualThreadFactory(scheduler1);
 74         Thread thread = factory.newThread(() -> {
 75             ref.set(VThreadScheduler.scheduler(Thread.currentThread()));
 76         });
 77         thread.start();
 78         thread.join();
 79         assertTrue(ref.get() == scheduler1);
 80     }
 81 
 82     /**
 83      * Test virtual thread creating a virtual thread that uses a custom scheduler.
 84      */
 85     @Test
 86     void testCustomScheduler2() throws Exception {
 87         VThreadRunner.run(this::testCustomScheduler1);
 88     }
 89 
 90     /**
 91      * Test virtual thread using custom scheduler creating a virtual thread.
 92      * The scheduler should be inherited.
 93      */
 94     @Test
 95     void testCustomScheduler3() throws Exception {
 96         var ref = new AtomicReference<Executor>();
 97         ThreadFactory factory = VThreadScheduler.virtualThreadFactory(scheduler1);
 98         Thread thread = factory.newThread(() -> {
 99             try {
100                 Thread.ofVirtual().start(() -> {
101                     ref.set(VThreadScheduler.scheduler(Thread.currentThread()));
102                 }).join();
103             } catch (Exception e) {
104                 e.printStackTrace();
105             }
106         });
107         thread.start();
108         thread.join();
109         assertTrue(ref.get() == scheduler1);
110     }
111 
112     /**
113      * Test virtual thread using custom scheduler creating a virtual thread
114      * that uses a different custom scheduler.
115      */
116     @Test
117     void testCustomScheduler4() throws Exception {
118         var ref = new AtomicReference<Executor>();
119         ThreadFactory factory1 = VThreadScheduler.virtualThreadFactory(scheduler1);
120         ThreadFactory factory2 = VThreadScheduler.virtualThreadFactory(scheduler2);
121         Thread thread1 = factory1.newThread(() -> {
122             try {
123                 Thread thread2 = factory2.newThread(() -> {
124                     ref.set(VThreadScheduler.scheduler(Thread.currentThread()));
125                 });
126                 thread2.start();
127                 thread2.join();
128             } catch (Exception e) {
129                 e.printStackTrace();
130             }
131         });
132         thread1.start();
133         thread1.join();
134         assertTrue(ref.get() == scheduler2);
135     }
136 
137     /**
138      * Test running task on a virtual thread, should thrown WrongThreadException.
139      */
140     @Test
141     void testBadCarrier() {
142         Executor scheduler = (task) -> {
143             var exc = new AtomicReference<Throwable>();
144             try {
145                 Thread.ofVirtual().start(() -> {
146                     try {
147                         task.run();
148                         fail();
149                     } catch (Throwable e) {
150                         exc.set(e);
151                     }
152                 }).join();
153             } catch (InterruptedException e) {
154                 fail();
155             }
156             assertTrue(exc.get() instanceof WrongThreadException);
157         };
158         ThreadFactory factory = VThreadScheduler.virtualThreadFactory(scheduler);
159         Thread thread = factory.newThread(LockSupport::park);
160         thread.start();
161     }
162 
163     /**
164      * Test parking with the virtual thread interrupt set, should not leak to the
165      * carrier thread when the task completes.
166      */
167     @Test
168     void testParkWithInterruptSet() {
169         Thread carrier = Thread.currentThread();
170         assumeFalse(carrier.isVirtual(), "Main thread is a virtual thread");
171         try {
172             ThreadFactory factory = VThreadScheduler.virtualThreadFactory(Runnable::run);
173             Thread vthread = factory.newThread(() -> {
174                 Thread.currentThread().interrupt();
175                 Thread.yield();
176             });
177             vthread.start();
178             assertTrue(vthread.isInterrupted());
179             assertFalse(carrier.isInterrupted());
180         } finally {
181             Thread.interrupted();
182         }
183     }
184 
185     /**
186      * Test terminating with the virtual thread interrupt set, should not leak to
187      * the carrier thread when the task completes.
188      */
189     @Test
190     void testTerminateWithInterruptSet() {
191         Thread carrier = Thread.currentThread();
192         assumeFalse(carrier.isVirtual(), "Main thread is a virtual thread");
193         try {
194             ThreadFactory factory = VThreadScheduler.virtualThreadFactory(Runnable::run);
195             Thread vthread = factory.newThread(() -> {
196                 Thread.currentThread().interrupt();
197             });
198             vthread.start();
199             assertTrue(vthread.isInterrupted());
200             assertFalse(carrier.isInterrupted());
201         } finally {
202             Thread.interrupted();
203         }
204     }
205 
206     /**
207      * Test running task with the carrier's interrupted status set.
208      */
209     @Test
210     void testRunWithInterruptSet() throws Exception {
211         assumeFalse(Thread.currentThread().isVirtual(), "Main thread is a virtual thread");
212         Executor scheduler = (task) -> {
213             Thread.currentThread().interrupt();
214             task.run();
215         };
216         ThreadFactory factory = VThreadScheduler.virtualThreadFactory(scheduler);
217         try {
218             AtomicBoolean interrupted = new AtomicBoolean();
219             Thread vthread = factory.newThread(() -> {
220                 interrupted.set(Thread.currentThread().isInterrupted());
221             });
222             vthread.start();
223             assertFalse(vthread.isInterrupted());
224         } finally {
225             Thread.interrupted();
226         }
227     }
228 
229     /**
230      * Test custom scheduler throwing OOME when starting a thread.
231      */
232     @Test
233     void testThreadStartOOME() throws Exception {
234         Executor scheduler = task -> {
235             System.err.println("OutOfMemoryError");
236             throw new OutOfMemoryError();
237         };
238         ThreadFactory factory = VThreadScheduler.virtualThreadFactory(scheduler);
239         Thread thread = factory.newThread(() -> { });
240         assertThrows(OutOfMemoryError.class, thread::start);
241     }
242 
243     /**
244      * Test custom scheduler throwing OOME when unparking a thread.
245      */
246     @Test
247     void testThreadUnparkOOME() throws Exception {
248         try (ExecutorService executor = Executors.newFixedThreadPool(1)) {
249             AtomicInteger counter = new AtomicInteger();
250             Executor scheduler = task -> {
251                 switch (counter.getAndIncrement()) {
252                     case 0 -> executor.execute(task);             // Thread.start
253                     case 1, 2 -> {                                // unpark attempt 1+2
254                         System.err.println("OutOfMemoryError");
255                         throw new OutOfMemoryError();
256                     }
257                     default -> executor.execute(task);
258                 }
259                 executor.execute(task);
260             };
261 
262             // start thread and wait for it to park
263             ThreadFactory factory = VThreadScheduler.virtualThreadFactory(scheduler);
264             var thread = factory.newThread(LockSupport::park);
265             thread.start();
266             await(thread, Thread.State.WAITING);
267 
268             // unpark thread, this should retry until OOME is not thrown
269             LockSupport.unpark(thread);
270             thread.join();
271         }








272 











273     }
274 
275     /**
276      * Waits for the given thread to reach a given state.
277      */
278     private void await(Thread thread, Thread.State expectedState) throws InterruptedException {
279         Thread.State state = thread.getState();
280         while (state != expectedState) {
281             assertTrue(state != Thread.State.TERMINATED, "Thread has terminated");
282             Thread.sleep(10);
283             state = thread.getState();
284         }
285     }
286 }

 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.
 22  */
 23 
 24 /**
 25  * @test
 26  * @summary Test virtual threads using a custom scheduler
 27  * @requires vm.continuations
 28  * @modules java.base/java.lang:+open
 29  * @library /test/lib
 30  * @run junit CustomScheduler
 31  */
 32 
 33 import java.lang.reflect.Field;
 34 import java.time.Duration;
 35 import java.util.ArrayList;
 36 import java.util.List;
 37 import java.util.concurrent.Executor;
 38 import java.util.concurrent.Executors;
 39 import java.util.concurrent.ExecutorService;
 40 import java.util.concurrent.atomic.AtomicBoolean;
 41 import java.util.concurrent.atomic.AtomicInteger;
 42 import java.util.concurrent.atomic.AtomicReference;
 43 import java.util.concurrent.locks.LockSupport;
 44 

 45 import jdk.test.lib.thread.VThreadRunner;
 46 import jdk.test.lib.thread.VThreadScheduler;
 47 import org.junit.jupiter.api.Test;
 48 import org.junit.jupiter.api.BeforeAll;
 49 import org.junit.jupiter.api.AfterAll;
 50 import static org.junit.jupiter.api.Assertions.*;
 51 import static org.junit.jupiter.api.Assumptions.*;
 52 
 53 class CustomScheduler {
 54     private static Thread.VirtualThreadScheduler defaultScheduler;
 55     private static ExecutorService threadPool1, threadPool2;
 56     private static Thread.VirtualThreadScheduler scheduler1, scheduler2;
 57 
 58     @BeforeAll
 59     static void setup() throws Exception {
 60         var ref = new AtomicReference<Thread.VirtualThreadScheduler>();
 61         Thread thread = Thread.startVirtualThread(() -> {
 62             ref.set(currentScheduler());
 63         });
 64         thread.join();
 65         defaultScheduler = ref.get();
 66 
 67         threadPool1 = Executors.newFixedThreadPool(1);
 68         threadPool2 = Executors.newFixedThreadPool(1);
 69         scheduler1 = adapt(threadPool1);
 70         scheduler2 = adapt(threadPool2);
 71     }
 72 
 73     @AfterAll
 74     static void shutdown() {
 75         threadPool1.shutdown();
 76         threadPool2.shutdown();
 77     }
 78 
 79     /**
 80      * Test platform thread creating a virtual thread that uses a custom scheduler.
 81      */
 82     @Test
 83     void testCustomScheduler1() throws Exception {
 84         var ref = new AtomicReference<Thread.VirtualThreadScheduler>();
 85         Thread thread = VThreadScheduler.virtualThreadBuilder(scheduler1).start(() -> {
 86             ref.set(currentScheduler());

 87         });

 88         thread.join();
 89         assertTrue(ref.get() == scheduler1);
 90     }
 91 
 92     /**
 93      * Test virtual thread creating a virtual thread that uses a custom scheduler.
 94      */
 95     @Test
 96     void testCustomScheduler2() throws Exception {
 97         VThreadRunner.run(this::testCustomScheduler1);
 98     }
 99 
100     /**
101      * Test virtual thread using custom scheduler creating a virtual thread that uses
102      * the default scheduler.
103      */
104     @Test
105     void testCustomScheduler3() throws Exception {
106         var ref = new AtomicReference<Thread.VirtualThreadScheduler>();
107         Thread thread = VThreadScheduler.virtualThreadBuilder(scheduler1).start(() -> {

108             try {
109                 Thread.ofVirtual().start(() -> {
110                     ref.set(currentScheduler());
111                 }).join();
112             } catch (Exception e) {
113                 e.printStackTrace();
114             }
115         });

116         thread.join();
117         assertTrue(ref.get() == defaultScheduler);
118     }
119 
120     /**
121      * Test virtual thread using custom scheduler creating a virtual thread
122      * that uses a different custom scheduler.
123      */
124     @Test
125     void testCustomScheduler4() throws Exception {
126         var ref = new AtomicReference<Thread.VirtualThreadScheduler>();
127         Thread thread1 = VThreadScheduler.virtualThreadBuilder(scheduler1).start(() -> {


128             try {
129                 Thread thread2 = VThreadScheduler.virtualThreadBuilder(scheduler2).start(() -> {
130                     ref.set(currentScheduler());
131                 });

132                 thread2.join();
133             } catch (Exception e) {
134                 e.printStackTrace();
135             }
136         });

137         thread1.join();
138         assertTrue(ref.get() == scheduler2);
139     }
140 
141     /**
142      * Test running task on a virtual thread, should thrown WrongThreadException.
143      */
144     @Test
145     void testBadCarrier() {
146         Executor executor = (task) -> {
147             var exc = new AtomicReference<Throwable>();
148             try {
149                 Thread.ofVirtual().start(() -> {
150                     try {
151                         task.run();
152                         fail();
153                     } catch (Throwable e) {
154                         exc.set(e);
155                     }
156                 }).join();
157             } catch (InterruptedException e) {
158                 fail();
159             }
160             assertTrue(exc.get() instanceof WrongThreadException);
161         };
162         var scheduler = adapt(executor);
163         VThreadScheduler.virtualThreadBuilder(scheduler).start(LockSupport::park);

164     }
165 
166     /**
167      * Test parking with the virtual thread interrupt set, should not leak to the
168      * carrier thread when the task completes.
169      */
170     @Test
171     void testParkWithInterruptSet() {
172         Thread carrier = Thread.currentThread();
173         assumeFalse(carrier.isVirtual(), "Main thread is a virtual thread");
174         try {
175             var scheduler = adapt(Runnable::run);
176             Thread vthread = VThreadScheduler.virtualThreadBuilder(scheduler).start(() -> {
177                 Thread.currentThread().interrupt();
178                 Thread.yield();
179             });

180             assertTrue(vthread.isInterrupted());
181             assertFalse(carrier.isInterrupted());
182         } finally {
183             Thread.interrupted();
184         }
185     }
186 
187     /**
188      * Test terminating with the virtual thread interrupt set, should not leak to
189      * the carrier thread when the task completes.
190      */
191     @Test
192     void testTerminateWithInterruptSet() {
193         Thread carrier = Thread.currentThread();
194         assumeFalse(carrier.isVirtual(), "Main thread is a virtual thread");
195         try {
196             var scheduler = adapt(Runnable::run);
197             Thread vthread = VThreadScheduler.virtualThreadBuilder(scheduler).start(() -> {
198                 Thread.currentThread().interrupt();
199             });

200             assertTrue(vthread.isInterrupted());
201             assertFalse(carrier.isInterrupted());
202         } finally {
203             Thread.interrupted();
204         }
205     }
206 
207     /**
208      * Test running task with the carrier's interrupted status set.
209      */
210     @Test
211     void testRunWithInterruptSet() throws Exception {
212         assumeFalse(Thread.currentThread().isVirtual(), "Main thread is a virtual thread");
213         var scheduler = adapt(task -> {
214             Thread.currentThread().interrupt();
215             task.run();
216         });

217         try {
218             AtomicBoolean interrupted = new AtomicBoolean();
219             Thread vthread = VThreadScheduler.virtualThreadBuilder(scheduler).start(() -> {
220                 interrupted.set(Thread.currentThread().isInterrupted());
221             });

222             assertFalse(vthread.isInterrupted());
223         } finally {
224             Thread.interrupted();
225         }
226     }
227 
228     /**
229      * Test custom scheduler throwing OOME when starting a thread.
230      */
231     @Test
232     void testThreadStartOOME() throws Exception {
233         var scheduler = adapt(task -> {
234             System.err.println("OutOfMemoryError");
235             throw new OutOfMemoryError();
236         });
237         Thread thread = VThreadScheduler.virtualThreadBuilder(scheduler).unstarted(() -> { });

238         assertThrows(OutOfMemoryError.class, thread::start);
239     }
240 
241     /**
242      * Test custom scheduler throwing OOME when unparking a thread.
243      */
244     @Test
245     void testThreadUnparkOOME() throws Exception {
246         try (ExecutorService executor = Executors.newFixedThreadPool(1)) {
247             AtomicInteger counter = new AtomicInteger();
248             var scheduler = adapt(task -> {
249                 switch (counter.getAndIncrement()) {
250                     case 0 -> executor.execute(task);             // Thread.start
251                     case 1, 2 -> {                                // unpark attempt 1+2
252                         System.err.println("OutOfMemoryError");
253                         throw new OutOfMemoryError();
254                     }
255                     default -> executor.execute(task);
256                 }
257                 executor.execute(task);
258             });
259 
260             // start thread and wait for it to park
261             var thread = VThreadScheduler.virtualThreadBuilder(scheduler).start(LockSupport::park);


262             await(thread, Thread.State.WAITING);
263 
264             // unpark thread, this should retry until OOME is not thrown
265             LockSupport.unpark(thread);
266             thread.join();
267         }
268     }
269 
270     /**
271      * Returns the scheduler for the current virtual thread.
272      */
273     private static Thread.VirtualThreadScheduler currentScheduler() {
274         return VThreadScheduler.scheduler(Thread.currentThread());
275     }
276 
277     private static Thread.VirtualThreadScheduler adapt(Executor executor) {
278         return new Thread.VirtualThreadScheduler() {
279             @Override
280             public void onStart(Thread.VirtualThreadTask task) {
281                 executor.execute(task);
282             }
283             @Override
284             public void onContinue(Thread.VirtualThreadTask task) {
285                 executor.execute(task);
286             }
287         };
288     }
289 
290     /**
291      * Waits for the given thread to reach a given state.
292      */
293     private static void await(Thread thread, Thread.State expectedState) throws InterruptedException {
294         Thread.State state = thread.getState();
295         while (state != expectedState) {
296             assertTrue(state != Thread.State.TERMINATED, "Thread has terminated");
297             Thread.sleep(10);
298             state = thread.getState();
299         }
300     }
301 }
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