test/tck/LockSupportTest.java

/*
 * Written by Doug Lea and Martin Buchholz with assistance from
 * members of JCP JSR-166 Expert Group and released to the public
 * domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 * Other contributors include Andrew Wright, Jeffrey Hayes,
 * Pat Fisher, Mike Judd.
 */

import junit.framework.*;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.LockSupport;
import static java.util.concurrent.TimeUnit.MILLISECONDS;

public class LockSupportTest extends JSR166TestCase {
    public static void main(String[] args) {
        junit.textui.TestRunner.run(suite());
    }

    public static Test suite() {
        return new TestSuite(LockSupportTest.class);
    }

    /**
     * Returns the blocker object used by tests in this file.
     * Any old object will do; we'll return a convenient one.
     */
    static Object theBlocker() {
        return LockSupportTest.class;
    }

    enum ParkMethod {
        park() {
            void park() {
                LockSupport.park();
            }
            void park(long millis) {
                throw new UnsupportedOperationException();
            }
        },
        parkUntil() {
            void park(long millis) {
                LockSupport.parkUntil(deadline(millis));
            }
        },
        parkNanos() {
            void park(long millis) {
                LockSupport.parkNanos(MILLISECONDS.toNanos(millis));
            }
        },
        parkBlocker() {
            void park() {
                LockSupport.park(theBlocker());
            }
            void park(long millis) {
                throw new UnsupportedOperationException();
            }
        },
        parkUntilBlocker() {
            void park(long millis) {
                LockSupport.parkUntil(theBlocker(), deadline(millis));
            }
        },
        parkNanosBlocker() {
            void park(long millis) {
                LockSupport.parkNanos(theBlocker(),
                                      MILLISECONDS.toNanos(millis));
            }
        };

        void park() { park(2 * LONG_DELAY_MS); }
        abstract void park(long millis);

        /** Returns a deadline to use with parkUntil. */
        long deadline(long millis) {
            // beware of rounding
            return System.currentTimeMillis() + millis + 1;
        }
    }

    /**
     * park is released by subsequent unpark
     */
    public void testParkBeforeUnpark_park() {
        testParkBeforeUnpark(ParkMethod.park);
    }
    public void testParkBeforeUnpark_parkNanos() {
        testParkBeforeUnpark(ParkMethod.parkNanos);
    }
    public void testParkBeforeUnpark_parkUntil() {
        testParkBeforeUnpark(ParkMethod.parkUntil);
    }
    public void testParkBeforeUnpark_parkBlocker() {
        testParkBeforeUnpark(ParkMethod.parkBlocker);
    }
    public void testParkBeforeUnpark_parkNanosBlocker() {
        testParkBeforeUnpark(ParkMethod.parkNanosBlocker);
    }
    public void testParkBeforeUnpark_parkUntilBlocker() {
        testParkBeforeUnpark(ParkMethod.parkUntilBlocker);
    }
    public void testParkBeforeUnpark(final ParkMethod parkMethod) {
        final CountDownLatch pleaseUnpark = new CountDownLatch(1);
        Thread t = newStartedThread(new CheckedRunnable() {
            public void realRun() {
                pleaseUnpark.countDown();
                parkMethod.park();
            }});

        await(pleaseUnpark);
        LockSupport.unpark(t);
        awaitTermination(t);
    }

    /**
     * park is released by preceding unpark
     */
    public void testParkAfterUnpark_park() {
        testParkAfterUnpark(ParkMethod.park);
    }
    public void testParkAfterUnpark_parkNanos() {
        testParkAfterUnpark(ParkMethod.parkNanos);
    }
    public void testParkAfterUnpark_parkUntil() {
        testParkAfterUnpark(ParkMethod.parkUntil);
    }
    public void testParkAfterUnpark_parkBlocker() {
        testParkAfterUnpark(ParkMethod.parkBlocker);
    }
    public void testParkAfterUnpark_parkNanosBlocker() {
        testParkAfterUnpark(ParkMethod.parkNanosBlocker);
    }
    public void testParkAfterUnpark_parkUntilBlocker() {
        testParkAfterUnpark(ParkMethod.parkUntilBlocker);
    }
    public void testParkAfterUnpark(final ParkMethod parkMethod) {
        final CountDownLatch pleaseUnpark = new CountDownLatch(1);
        final AtomicBoolean pleasePark = new AtomicBoolean(false);
        Thread t = newStartedThread(new CheckedRunnable() {
            public void realRun() {
                pleaseUnpark.countDown();
                while (!pleasePark.get())
                    Thread.yield();
                parkMethod.park();
            }});

        await(pleaseUnpark);
        LockSupport.unpark(t);
        pleasePark.set(true);
        awaitTermination(t);
    }

    /**
     * park is released by subsequent interrupt
     */
    public void testParkBeforeInterrupt_park() {
        testParkBeforeInterrupt(ParkMethod.park);
    }
    public void testParkBeforeInterrupt_parkNanos() {
        testParkBeforeInterrupt(ParkMethod.parkNanos);
    }
    public void testParkBeforeInterrupt_parkUntil() {
        testParkBeforeInterrupt(ParkMethod.parkUntil);
    }
    public void testParkBeforeInterrupt_parkBlocker() {
        testParkBeforeInterrupt(ParkMethod.parkBlocker);
    }
    public void testParkBeforeInterrupt_parkNanosBlocker() {
        testParkBeforeInterrupt(ParkMethod.parkNanosBlocker);
    }
    public void testParkBeforeInterrupt_parkUntilBlocker() {
        testParkBeforeInterrupt(ParkMethod.parkUntilBlocker);
    }
    public void testParkBeforeInterrupt(final ParkMethod parkMethod) {
        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
        Thread t = newStartedThread(new CheckedRunnable() {
            public void realRun() {
                pleaseInterrupt.countDown();
                do {
                    parkMethod.park();
                    // park may return spuriously
                } while (! Thread.currentThread().isInterrupted());
            }});

        await(pleaseInterrupt);
        assertThreadStaysAlive(t);
        t.interrupt();
        awaitTermination(t);
    }

    /**
     * park is released by preceding interrupt
     */
    public void testParkAfterInterrupt_park() {
        testParkAfterInterrupt(ParkMethod.park);
    }
    public void testParkAfterInterrupt_parkNanos() {
        testParkAfterInterrupt(ParkMethod.parkNanos);
    }
    public void testParkAfterInterrupt_parkUntil() {
        testParkAfterInterrupt(ParkMethod.parkUntil);
    }
    public void testParkAfterInterrupt_parkBlocker() {
        testParkAfterInterrupt(ParkMethod.parkBlocker);
    }
    public void testParkAfterInterrupt_parkNanosBlocker() {
        testParkAfterInterrupt(ParkMethod.parkNanosBlocker);
    }
    public void testParkAfterInterrupt_parkUntilBlocker() {
        testParkAfterInterrupt(ParkMethod.parkUntilBlocker);
    }
    public void testParkAfterInterrupt(final ParkMethod parkMethod) {
        final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
        final AtomicBoolean pleasePark = new AtomicBoolean(false);
        Thread t = newStartedThread(new CheckedRunnable() {
            public void realRun() throws Exception {
                pleaseInterrupt.countDown();
                while (!pleasePark.get())
                    Thread.yield();
                assertTrue(Thread.currentThread().isInterrupted());
                parkMethod.park();
                assertTrue(Thread.currentThread().isInterrupted());
            }});

        await(pleaseInterrupt);
        t.interrupt();
        pleasePark.set(true);
        awaitTermination(t);
    }

    /**
     * timed park times out if not unparked
     */
    public void testParkTimesOut_parkNanos() {
        testParkTimesOut(ParkMethod.parkNanos);
    }
    public void testParkTimesOut_parkUntil() {
        testParkTimesOut(ParkMethod.parkUntil);
    }
    public void testParkTimesOut_parkNanosBlocker() {
        testParkTimesOut(ParkMethod.parkNanosBlocker);
    }
    public void testParkTimesOut_parkUntilBlocker() {
        testParkTimesOut(ParkMethod.parkUntilBlocker);
    }
    public void testParkTimesOut(final ParkMethod parkMethod) {
        Thread t = newStartedThread(new CheckedRunnable() {
            public void realRun() {
                for (;;) {
                    long startTime = System.nanoTime();
                    parkMethod.park(timeoutMillis());
                    // park may return spuriously
                    if (millisElapsedSince(startTime) >= timeoutMillis())
                        return;
                }
            }});

        awaitTermination(t);
    }

    /**
     * getBlocker(null) throws NullPointerException
     */
    public void testGetBlockerNull() {
        try {
            LockSupport.getBlocker(null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * getBlocker returns the blocker object passed to park
     */
    public void testGetBlocker_parkBlocker() {
        testGetBlocker(ParkMethod.parkBlocker);
    }
    public void testGetBlocker_parkNanosBlocker() {
        testGetBlocker(ParkMethod.parkNanosBlocker);
    }
    public void testGetBlocker_parkUntilBlocker() {
        testGetBlocker(ParkMethod.parkUntilBlocker);
    }
    public void testGetBlocker(final ParkMethod parkMethod) {
        final CountDownLatch started = new CountDownLatch(1);
        Thread t = newStartedThread(new CheckedRunnable() {
            public void realRun() {
                Thread t = Thread.currentThread();
                started.countDown();
                do {
                    assertNull(LockSupport.getBlocker(t));
                    parkMethod.park();
                    assertNull(LockSupport.getBlocker(t));
                    // park may return spuriously
                } while (! Thread.currentThread().isInterrupted());
            }});

        long startTime = System.nanoTime();
        await(started);
        for (;;) {
            Object x = LockSupport.getBlocker(t);
            if (x == theBlocker()) { // success
                t.interrupt();
                awaitTermination(t);
                assertNull(LockSupport.getBlocker(t));
                return;
            } else {
                assertNull(x);  // ok
                if (millisElapsedSince(startTime) > LONG_DELAY_MS)
                    fail("timed out");
                Thread.yield();
            }
        }
    }

    /**
     * timed park(0) returns immediately.
     *
     * Requires hotspot fix for:
     * 6763959 java.util.concurrent.locks.LockSupport.parkUntil(0) blocks forever
     * which is in jdk7-b118 and 6u25.
     */
    public void testPark0_parkNanos() {
        testPark0(ParkMethod.parkNanos);
    }
    public void testPark0_parkUntil() {
        testPark0(ParkMethod.parkUntil);
    }
    public void testPark0_parkNanosBlocker() {
        testPark0(ParkMethod.parkNanosBlocker);
    }
    public void testPark0_parkUntilBlocker() {
        testPark0(ParkMethod.parkUntilBlocker);
    }
    public void testPark0(final ParkMethod parkMethod) {
        Thread t = newStartedThread(new CheckedRunnable() {
            public void realRun() {
                parkMethod.park(0L);
            }});

        awaitTermination(t);
    }

    /**
     * timed park(Long.MIN_VALUE) returns immediately.
     */
    public void testParkNeg_parkNanos() {
        testParkNeg(ParkMethod.parkNanos);
    }
    public void testParkNeg_parkUntil() {
        testParkNeg(ParkMethod.parkUntil);
    }
    public void testParkNeg_parkNanosBlocker() {
        testParkNeg(ParkMethod.parkNanosBlocker);
    }
    public void testParkNeg_parkUntilBlocker() {
        testParkNeg(ParkMethod.parkUntilBlocker);
    }
    public void testParkNeg(final ParkMethod parkMethod) {
        Thread t = newStartedThread(new CheckedRunnable() {
            public void realRun() {
                parkMethod.park(Long.MIN_VALUE);
            }});

        awaitTermination(t);
    }
}
Revision:	1.23
Committed:	Sat May 28 22:21:58 2011 UTC (12 years, 11 months ago) by jsr166
Branch:	MAIN
Changes since 1.22:	+255 -246 lines
Log Message:	test blocker methods; extreme refactor
#	User	Rev	Content
1	dl	1.1	/*
2	jsr166	1.15	* Written by Doug Lea and Martin Buchholz with assistance from
3			* members of JCP JSR-166 Expert Group and released to the public
4			* domain, as explained at
5	jsr166	1.18	* http://creativecommons.org/publicdomain/zero/1.0/
6	jsr166	1.8	* Other contributors include Andrew Wright, Jeffrey Hayes,
7			* Pat Fisher, Mike Judd.
8	dl	1.1	*/
9
10			import junit.framework.*;
11	jsr166	1.23	import java.util.concurrent.CountDownLatch;
12	jsr166	1.15	import java.util.concurrent.atomic.AtomicBoolean;
13	jsr166	1.23	import java.util.concurrent.locks.LockSupport;
14			import static java.util.concurrent.TimeUnit.MILLISECONDS;
15	dl	1.1
16	jsr166	1.10	public class LockSupportTest extends JSR166TestCase {
17	dl	1.1	public static void main(String[] args) {
18	jsr166	1.14	junit.textui.TestRunner.run(suite());
19	dl	1.1	}
20	jsr166	1.15
21	dl	1.1	public static Test suite() {
22	jsr166	1.12	return new TestSuite(LockSupportTest.class);
23	dl	1.1	}
24
25	dl	1.3	/**
26	jsr166	1.23	* Returns the blocker object used by tests in this file.
27			* Any old object will do; we'll return a convenient one.
28	dl	1.3	*/
29	jsr166	1.23	static Object theBlocker() {
30			return LockSupportTest.class;
31			}
32
33			enum ParkMethod {
34			park() {
35			void park() {
36	jsr166	1.11	LockSupport.park();
37	jsr166	1.23	}
38			void park(long millis) {
39			throw new UnsupportedOperationException();
40			}
41			},
42			parkUntil() {
43			void park(long millis) {
44			LockSupport.parkUntil(deadline(millis));
45			}
46			},
47			parkNanos() {
48			void park(long millis) {
49			LockSupport.parkNanos(MILLISECONDS.toNanos(millis));
50			}
51			},
52			parkBlocker() {
53			void park() {
54			LockSupport.park(theBlocker());
55			}
56			void park(long millis) {
57			throw new UnsupportedOperationException();
58			}
59			},
60			parkUntilBlocker() {
61			void park(long millis) {
62			LockSupport.parkUntil(theBlocker(), deadline(millis));
63			}
64			},
65			parkNanosBlocker() {
66			void park(long millis) {
67			LockSupport.parkNanos(theBlocker(),
68			MILLISECONDS.toNanos(millis));
69			}
70			};
71
72			void park() { park(2 * LONG_DELAY_MS); }
73			abstract void park(long millis);
74
75			/** Returns a deadline to use with parkUntil. */
76			long deadline(long millis) {
77			// beware of rounding
78			return System.currentTimeMillis() + millis + 1;
79			}
80	jsr166	1.15	}
81
82			/**
83	jsr166	1.23	* park is released by subsequent unpark
84	jsr166	1.15	*/
85	jsr166	1.23	public void testParkBeforeUnpark_park() {
86			testParkBeforeUnpark(ParkMethod.park);
87			}
88			public void testParkBeforeUnpark_parkNanos() {
89			testParkBeforeUnpark(ParkMethod.parkNanos);
90			}
91			public void testParkBeforeUnpark_parkUntil() {
92			testParkBeforeUnpark(ParkMethod.parkUntil);
93			}
94			public void testParkBeforeUnpark_parkBlocker() {
95			testParkBeforeUnpark(ParkMethod.parkBlocker);
96			}
97			public void testParkBeforeUnpark_parkNanosBlocker() {
98			testParkBeforeUnpark(ParkMethod.parkNanosBlocker);
99			}
100			public void testParkBeforeUnpark_parkUntilBlocker() {
101			testParkBeforeUnpark(ParkMethod.parkUntilBlocker);
102	jsr166	1.15	}
103	jsr166	1.23	public void testParkBeforeUnpark(final ParkMethod parkMethod) {
104			final CountDownLatch pleaseUnpark = new CountDownLatch(1);
105	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
106	jsr166	1.15	public void realRun() {
107	jsr166	1.23	pleaseUnpark.countDown();
108			parkMethod.park();
109	jsr166	1.15	}});
110
111	jsr166	1.23	await(pleaseUnpark);
112	jsr166	1.11	LockSupport.unpark(t);
113	jsr166	1.23	awaitTermination(t);
114	dl	1.1	}
115
116	dl	1.3	/**
117	jsr166	1.15	* park is released by preceding unpark
118	dl	1.4	*/
119	jsr166	1.23	public void testParkAfterUnpark_park() {
120			testParkAfterUnpark(ParkMethod.park);
121			}
122			public void testParkAfterUnpark_parkNanos() {
123			testParkAfterUnpark(ParkMethod.parkNanos);
124			}
125			public void testParkAfterUnpark_parkUntil() {
126			testParkAfterUnpark(ParkMethod.parkUntil);
127			}
128			public void testParkAfterUnpark_parkBlocker() {
129			testParkAfterUnpark(ParkMethod.parkBlocker);
130			}
131			public void testParkAfterUnpark_parkNanosBlocker() {
132			testParkAfterUnpark(ParkMethod.parkNanosBlocker);
133	dl	1.4	}
134	jsr166	1.23	public void testParkAfterUnpark_parkUntilBlocker() {
135			testParkAfterUnpark(ParkMethod.parkUntilBlocker);
136	jsr166	1.15	}
137	jsr166	1.23	public void testParkAfterUnpark(final ParkMethod parkMethod) {
138			final CountDownLatch pleaseUnpark = new CountDownLatch(1);
139			final AtomicBoolean pleasePark = new AtomicBoolean(false);
140	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
141	jsr166	1.23	public void realRun() {
142			pleaseUnpark.countDown();
143			while (!pleasePark.get())
144	jsr166	1.15	Thread.yield();
145	jsr166	1.23	parkMethod.park();
146	jsr166	1.15	}});
147
148	jsr166	1.23	await(pleaseUnpark);
149	jsr166	1.15	LockSupport.unpark(t);
150	jsr166	1.23	pleasePark.set(true);
151			awaitTermination(t);
152	jsr166	1.15	}
153
154			/**
155			* park is released by subsequent interrupt
156			*/
157	jsr166	1.23	public void testParkBeforeInterrupt_park() {
158			testParkBeforeInterrupt(ParkMethod.park);
159			}
160			public void testParkBeforeInterrupt_parkNanos() {
161			testParkBeforeInterrupt(ParkMethod.parkNanos);
162			}
163			public void testParkBeforeInterrupt_parkUntil() {
164			testParkBeforeInterrupt(ParkMethod.parkUntil);
165			}
166			public void testParkBeforeInterrupt_parkBlocker() {
167			testParkBeforeInterrupt(ParkMethod.parkBlocker);
168			}
169			public void testParkBeforeInterrupt_parkNanosBlocker() {
170			testParkBeforeInterrupt(ParkMethod.parkNanosBlocker);
171			}
172			public void testParkBeforeInterrupt_parkUntilBlocker() {
173			testParkBeforeInterrupt(ParkMethod.parkUntilBlocker);
174			}
175			public void testParkBeforeInterrupt(final ParkMethod parkMethod) {
176			final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
177	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
178	jsr166	1.12	public void realRun() {
179	jsr166	1.23	pleaseInterrupt.countDown();
180	jsr166	1.17	do {
181	jsr166	1.23	parkMethod.park();
182	jsr166	1.17	// park may return spuriously
183			} while (! Thread.currentThread().isInterrupted());
184	jsr166	1.15	}});
185
186	jsr166	1.23	await(pleaseInterrupt);
187			assertThreadStaysAlive(t);
188	jsr166	1.15	t.interrupt();
189	jsr166	1.23	awaitTermination(t);
190	jsr166	1.15	}
191
192			/**
193	jsr166	1.23	* park is released by preceding interrupt
194	jsr166	1.15	*/
195	jsr166	1.23	public void testParkAfterInterrupt_park() {
196			testParkAfterInterrupt(ParkMethod.park);
197			}
198			public void testParkAfterInterrupt_parkNanos() {
199			testParkAfterInterrupt(ParkMethod.parkNanos);
200			}
201			public void testParkAfterInterrupt_parkUntil() {
202			testParkAfterInterrupt(ParkMethod.parkUntil);
203			}
204			public void testParkAfterInterrupt_parkBlocker() {
205			testParkAfterInterrupt(ParkMethod.parkBlocker);
206			}
207			public void testParkAfterInterrupt_parkNanosBlocker() {
208			testParkAfterInterrupt(ParkMethod.parkNanosBlocker);
209	dl	1.4	}
210	jsr166	1.23	public void testParkAfterInterrupt_parkUntilBlocker() {
211			testParkAfterInterrupt(ParkMethod.parkUntilBlocker);
212	jsr166	1.15	}
213	jsr166	1.23	public void testParkAfterInterrupt(final ParkMethod parkMethod) {
214			final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
215			final AtomicBoolean pleasePark = new AtomicBoolean(false);
216	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
217	jsr166	1.15	public void realRun() throws Exception {
218	jsr166	1.23	pleaseInterrupt.countDown();
219			while (!pleasePark.get())
220	jsr166	1.15	Thread.yield();
221			assertTrue(Thread.currentThread().isInterrupted());
222	jsr166	1.23	parkMethod.park();
223	jsr166	1.15	assertTrue(Thread.currentThread().isInterrupted());
224			}});
225
226	jsr166	1.23	await(pleaseInterrupt);
227	jsr166	1.15	t.interrupt();
228	jsr166	1.23	pleasePark.set(true);
229			awaitTermination(t);
230	jsr166	1.15	}
231
232			/**
233	jsr166	1.23	* timed park times out if not unparked
234	jsr166	1.15	*/
235	jsr166	1.23	public void testParkTimesOut_parkNanos() {
236			testParkTimesOut(ParkMethod.parkNanos);
237			}
238			public void testParkTimesOut_parkUntil() {
239			testParkTimesOut(ParkMethod.parkUntil);
240			}
241			public void testParkTimesOut_parkNanosBlocker() {
242			testParkTimesOut(ParkMethod.parkNanosBlocker);
243			}
244			public void testParkTimesOut_parkUntilBlocker() {
245			testParkTimesOut(ParkMethod.parkUntilBlocker);
246			}
247			public void testParkTimesOut(final ParkMethod parkMethod) {
248	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
249	jsr166	1.23	public void realRun() {
250			for (;;) {
251			long startTime = System.nanoTime();
252			parkMethod.park(timeoutMillis());
253			// park may return spuriously
254			if (millisElapsedSince(startTime) >= timeoutMillis())
255			return;
256			}
257	jsr166	1.15	}});
258
259	jsr166	1.23	awaitTermination(t);
260	jsr166	1.15	}
261
262			/**
263	jsr166	1.23	* getBlocker(null) throws NullPointerException
264	jsr166	1.15	*/
265	jsr166	1.23	public void testGetBlockerNull() {
266			try {
267			LockSupport.getBlocker(null);
268			shouldThrow();
269			} catch (NullPointerException success) {}
270	dl	1.4	}
271
272			/**
273	jsr166	1.23	* getBlocker returns the blocker object passed to park
274	dl	1.3	*/
275	jsr166	1.23	public void testGetBlocker_parkBlocker() {
276			testGetBlocker(ParkMethod.parkBlocker);
277			}
278			public void testGetBlocker_parkNanosBlocker() {
279			testGetBlocker(ParkMethod.parkNanosBlocker);
280			}
281			public void testGetBlocker_parkUntilBlocker() {
282			testGetBlocker(ParkMethod.parkUntilBlocker);
283			}
284			public void testGetBlocker(final ParkMethod parkMethod) {
285			final CountDownLatch started = new CountDownLatch(1);
286	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
287	jsr166	1.12	public void realRun() {
288	jsr166	1.23	Thread t = Thread.currentThread();
289			started.countDown();
290			do {
291			assertNull(LockSupport.getBlocker(t));
292			parkMethod.park();
293			assertNull(LockSupport.getBlocker(t));
294			// park may return spuriously
295			} while (! Thread.currentThread().isInterrupted());
296	jsr166	1.11	}});
297
298	jsr166	1.23	long startTime = System.nanoTime();
299			await(started);
300			for (;;) {
301			Object x = LockSupport.getBlocker(t);
302			if (x == theBlocker()) { // success
303			t.interrupt();
304			awaitTermination(t);
305			assertNull(LockSupport.getBlocker(t));
306			return;
307			} else {
308			assertNull(x); // ok
309			if (millisElapsedSince(startTime) > LONG_DELAY_MS)
310			fail("timed out");
311			Thread.yield();
312			}
313			}
314	dl	1.1	}
315
316	dl	1.3	/**
317	jsr166	1.23	* timed park(0) returns immediately.
318			*
319			* Requires hotspot fix for:
320			* 6763959 java.util.concurrent.locks.LockSupport.parkUntil(0) blocks forever
321			* which is in jdk7-b118 and 6u25.
322	dl	1.3	*/
323	jsr166	1.23	public void testPark0_parkNanos() {
324			testPark0(ParkMethod.parkNanos);
325			}
326			public void testPark0_parkUntil() {
327			testPark0(ParkMethod.parkUntil);
328			}
329			public void testPark0_parkNanosBlocker() {
330			testPark0(ParkMethod.parkNanosBlocker);
331			}
332			public void testPark0_parkUntilBlocker() {
333			testPark0(ParkMethod.parkUntilBlocker);
334			}
335			public void testPark0(final ParkMethod parkMethod) {
336	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
337	jsr166	1.12	public void realRun() {
338	jsr166	1.23	parkMethod.park(0L);
339	jsr166	1.15	}});
340
341	jsr166	1.23	awaitTermination(t);
342	jsr166	1.15	}
343
344			/**
345	jsr166	1.23	* timed park(Long.MIN_VALUE) returns immediately.
346	jsr166	1.20	*/
347	jsr166	1.23	public void testParkNeg_parkNanos() {
348			testParkNeg(ParkMethod.parkNanos);
349			}
350			public void testParkNeg_parkUntil() {
351			testParkNeg(ParkMethod.parkUntil);
352			}
353			public void testParkNeg_parkNanosBlocker() {
354			testParkNeg(ParkMethod.parkNanosBlocker);
355			}
356			public void testParkNeg_parkUntilBlocker() {
357			testParkNeg(ParkMethod.parkUntilBlocker);
358	jsr166	1.20	}
359	jsr166	1.23	public void testParkNeg(final ParkMethod parkMethod) {
360	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
361	jsr166	1.15	public void realRun() {
362	jsr166	1.23	parkMethod.park(Long.MIN_VALUE);
363	jsr166	1.11	}});
364
365	jsr166	1.21	awaitTermination(t);
366	dl	1.1	}
367			}