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 static java.util.concurrent.TimeUnit.MILLISECONDS;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.LockSupport;

import junit.framework.Test;
import junit.framework.TestSuite;

public class LockSupportTest extends JSR166TestCase {
    public static void main(String[] args) {
        main(suite(), args);
    }

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

    static {
        // Reduce the risk of rare disastrous classloading in first call to
        // LockSupport.park: https://bugs.openjdk.java.net/browse/JDK-8074773
        Class<?> ensureLoaded = LockSupport.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.interrupted());
            }});

        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 (int tries = MAX_SPURIOUS_WAKEUPS; tries-->0; ) {
                    long startTime = System.nanoTime();
                    parkMethod.park(timeoutMillis());
                    // park may return spuriously
                    if (millisElapsedSince(startTime) >= timeoutMillis())
                        return;
                }
                fail("too many consecutive spurious wakeups?");
            }});

        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.interrupted());
            }});

        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:	1.28
Committed:	Fri May 12 18:23:11 2017 UTC (7 years ago) by jsr166
Branch:	MAIN
Changes since 1.27:	+2 -2 lines
Log Message:	prefer Thread.interrupted() to Thread.isInterrupted() where possible
#	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	jsr166	1.24	import static java.util.concurrent.TimeUnit.MILLISECONDS;
11
12	jsr166	1.23	import java.util.concurrent.CountDownLatch;
13	jsr166	1.15	import java.util.concurrent.atomic.AtomicBoolean;
14	jsr166	1.23	import java.util.concurrent.locks.LockSupport;
15	jsr166	1.24
16			import junit.framework.Test;
17			import junit.framework.TestSuite;
18	dl	1.1
19	jsr166	1.10	public class LockSupportTest extends JSR166TestCase {
20	dl	1.1	public static void main(String[] args) {
21	jsr166	1.25	main(suite(), args);
22	dl	1.1	}
23	jsr166	1.15
24	dl	1.1	public static Test suite() {
25	jsr166	1.12	return new TestSuite(LockSupportTest.class);
26	dl	1.1	}
27
28	jsr166	1.26	static {
29			// Reduce the risk of rare disastrous classloading in first call to
30			// LockSupport.park: https://bugs.openjdk.java.net/browse/JDK-8074773
31			Class<?> ensureLoaded = LockSupport.class;
32			}
33
34	dl	1.3	/**
35	jsr166	1.23	* Returns the blocker object used by tests in this file.
36			* Any old object will do; we'll return a convenient one.
37	dl	1.3	*/
38	jsr166	1.23	static Object theBlocker() {
39			return LockSupportTest.class;
40			}
41
42			enum ParkMethod {
43			park() {
44			void park() {
45	jsr166	1.11	LockSupport.park();
46	jsr166	1.23	}
47			void park(long millis) {
48			throw new UnsupportedOperationException();
49			}
50			},
51			parkUntil() {
52			void park(long millis) {
53			LockSupport.parkUntil(deadline(millis));
54			}
55			},
56			parkNanos() {
57			void park(long millis) {
58			LockSupport.parkNanos(MILLISECONDS.toNanos(millis));
59			}
60			},
61			parkBlocker() {
62			void park() {
63			LockSupport.park(theBlocker());
64			}
65			void park(long millis) {
66			throw new UnsupportedOperationException();
67			}
68			},
69			parkUntilBlocker() {
70			void park(long millis) {
71			LockSupport.parkUntil(theBlocker(), deadline(millis));
72			}
73			},
74			parkNanosBlocker() {
75			void park(long millis) {
76			LockSupport.parkNanos(theBlocker(),
77			MILLISECONDS.toNanos(millis));
78			}
79			};
80
81			void park() { park(2 * LONG_DELAY_MS); }
82			abstract void park(long millis);
83
84			/** Returns a deadline to use with parkUntil. */
85			long deadline(long millis) {
86			// beware of rounding
87			return System.currentTimeMillis() + millis + 1;
88			}
89	jsr166	1.15	}
90
91			/**
92	jsr166	1.23	* park is released by subsequent unpark
93	jsr166	1.15	*/
94	jsr166	1.23	public void testParkBeforeUnpark_park() {
95			testParkBeforeUnpark(ParkMethod.park);
96			}
97			public void testParkBeforeUnpark_parkNanos() {
98			testParkBeforeUnpark(ParkMethod.parkNanos);
99			}
100			public void testParkBeforeUnpark_parkUntil() {
101			testParkBeforeUnpark(ParkMethod.parkUntil);
102			}
103			public void testParkBeforeUnpark_parkBlocker() {
104			testParkBeforeUnpark(ParkMethod.parkBlocker);
105			}
106			public void testParkBeforeUnpark_parkNanosBlocker() {
107			testParkBeforeUnpark(ParkMethod.parkNanosBlocker);
108			}
109			public void testParkBeforeUnpark_parkUntilBlocker() {
110			testParkBeforeUnpark(ParkMethod.parkUntilBlocker);
111	jsr166	1.15	}
112	jsr166	1.23	public void testParkBeforeUnpark(final ParkMethod parkMethod) {
113			final CountDownLatch pleaseUnpark = new CountDownLatch(1);
114	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
115	jsr166	1.15	public void realRun() {
116	jsr166	1.23	pleaseUnpark.countDown();
117			parkMethod.park();
118	jsr166	1.15	}});
119
120	jsr166	1.23	await(pleaseUnpark);
121	jsr166	1.11	LockSupport.unpark(t);
122	jsr166	1.23	awaitTermination(t);
123	dl	1.1	}
124
125	dl	1.3	/**
126	jsr166	1.15	* park is released by preceding unpark
127	dl	1.4	*/
128	jsr166	1.23	public void testParkAfterUnpark_park() {
129			testParkAfterUnpark(ParkMethod.park);
130			}
131			public void testParkAfterUnpark_parkNanos() {
132			testParkAfterUnpark(ParkMethod.parkNanos);
133			}
134			public void testParkAfterUnpark_parkUntil() {
135			testParkAfterUnpark(ParkMethod.parkUntil);
136			}
137			public void testParkAfterUnpark_parkBlocker() {
138			testParkAfterUnpark(ParkMethod.parkBlocker);
139			}
140			public void testParkAfterUnpark_parkNanosBlocker() {
141			testParkAfterUnpark(ParkMethod.parkNanosBlocker);
142	dl	1.4	}
143	jsr166	1.23	public void testParkAfterUnpark_parkUntilBlocker() {
144			testParkAfterUnpark(ParkMethod.parkUntilBlocker);
145	jsr166	1.15	}
146	jsr166	1.23	public void testParkAfterUnpark(final ParkMethod parkMethod) {
147			final CountDownLatch pleaseUnpark = new CountDownLatch(1);
148			final AtomicBoolean pleasePark = new AtomicBoolean(false);
149	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
150	jsr166	1.23	public void realRun() {
151			pleaseUnpark.countDown();
152			while (!pleasePark.get())
153	jsr166	1.15	Thread.yield();
154	jsr166	1.23	parkMethod.park();
155	jsr166	1.15	}});
156
157	jsr166	1.23	await(pleaseUnpark);
158	jsr166	1.15	LockSupport.unpark(t);
159	jsr166	1.23	pleasePark.set(true);
160			awaitTermination(t);
161	jsr166	1.15	}
162
163			/**
164			* park is released by subsequent interrupt
165			*/
166	jsr166	1.23	public void testParkBeforeInterrupt_park() {
167			testParkBeforeInterrupt(ParkMethod.park);
168			}
169			public void testParkBeforeInterrupt_parkNanos() {
170			testParkBeforeInterrupt(ParkMethod.parkNanos);
171			}
172			public void testParkBeforeInterrupt_parkUntil() {
173			testParkBeforeInterrupt(ParkMethod.parkUntil);
174			}
175			public void testParkBeforeInterrupt_parkBlocker() {
176			testParkBeforeInterrupt(ParkMethod.parkBlocker);
177			}
178			public void testParkBeforeInterrupt_parkNanosBlocker() {
179			testParkBeforeInterrupt(ParkMethod.parkNanosBlocker);
180			}
181			public void testParkBeforeInterrupt_parkUntilBlocker() {
182			testParkBeforeInterrupt(ParkMethod.parkUntilBlocker);
183			}
184			public void testParkBeforeInterrupt(final ParkMethod parkMethod) {
185			final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
186	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
187	jsr166	1.12	public void realRun() {
188	jsr166	1.23	pleaseInterrupt.countDown();
189	jsr166	1.17	do {
190	jsr166	1.23	parkMethod.park();
191	jsr166	1.17	// park may return spuriously
192	jsr166	1.28	} while (! Thread.interrupted());
193	jsr166	1.15	}});
194
195	jsr166	1.23	await(pleaseInterrupt);
196			assertThreadStaysAlive(t);
197	jsr166	1.15	t.interrupt();
198	jsr166	1.23	awaitTermination(t);
199	jsr166	1.15	}
200
201			/**
202	jsr166	1.23	* park is released by preceding interrupt
203	jsr166	1.15	*/
204	jsr166	1.23	public void testParkAfterInterrupt_park() {
205			testParkAfterInterrupt(ParkMethod.park);
206			}
207			public void testParkAfterInterrupt_parkNanos() {
208			testParkAfterInterrupt(ParkMethod.parkNanos);
209			}
210			public void testParkAfterInterrupt_parkUntil() {
211			testParkAfterInterrupt(ParkMethod.parkUntil);
212			}
213			public void testParkAfterInterrupt_parkBlocker() {
214			testParkAfterInterrupt(ParkMethod.parkBlocker);
215			}
216			public void testParkAfterInterrupt_parkNanosBlocker() {
217			testParkAfterInterrupt(ParkMethod.parkNanosBlocker);
218	dl	1.4	}
219	jsr166	1.23	public void testParkAfterInterrupt_parkUntilBlocker() {
220			testParkAfterInterrupt(ParkMethod.parkUntilBlocker);
221	jsr166	1.15	}
222	jsr166	1.23	public void testParkAfterInterrupt(final ParkMethod parkMethod) {
223			final CountDownLatch pleaseInterrupt = new CountDownLatch(1);
224			final AtomicBoolean pleasePark = new AtomicBoolean(false);
225	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
226	jsr166	1.15	public void realRun() throws Exception {
227	jsr166	1.23	pleaseInterrupt.countDown();
228			while (!pleasePark.get())
229	jsr166	1.15	Thread.yield();
230			assertTrue(Thread.currentThread().isInterrupted());
231	jsr166	1.23	parkMethod.park();
232	jsr166	1.15	assertTrue(Thread.currentThread().isInterrupted());
233			}});
234
235	jsr166	1.23	await(pleaseInterrupt);
236	jsr166	1.15	t.interrupt();
237	jsr166	1.23	pleasePark.set(true);
238			awaitTermination(t);
239	jsr166	1.15	}
240
241			/**
242	jsr166	1.23	* timed park times out if not unparked
243	jsr166	1.15	*/
244	jsr166	1.23	public void testParkTimesOut_parkNanos() {
245			testParkTimesOut(ParkMethod.parkNanos);
246			}
247			public void testParkTimesOut_parkUntil() {
248			testParkTimesOut(ParkMethod.parkUntil);
249			}
250			public void testParkTimesOut_parkNanosBlocker() {
251			testParkTimesOut(ParkMethod.parkNanosBlocker);
252			}
253			public void testParkTimesOut_parkUntilBlocker() {
254			testParkTimesOut(ParkMethod.parkUntilBlocker);
255			}
256			public void testParkTimesOut(final ParkMethod parkMethod) {
257	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
258	jsr166	1.23	public void realRun() {
259	jsr166	1.27	for (int tries = MAX_SPURIOUS_WAKEUPS; tries-->0; ) {
260	jsr166	1.23	long startTime = System.nanoTime();
261			parkMethod.park(timeoutMillis());
262			// park may return spuriously
263			if (millisElapsedSince(startTime) >= timeoutMillis())
264			return;
265			}
266	jsr166	1.27	fail("too many consecutive spurious wakeups?");
267	jsr166	1.15	}});
268
269	jsr166	1.23	awaitTermination(t);
270	jsr166	1.15	}
271
272			/**
273	jsr166	1.23	* getBlocker(null) throws NullPointerException
274	jsr166	1.15	*/
275	jsr166	1.23	public void testGetBlockerNull() {
276			try {
277			LockSupport.getBlocker(null);
278			shouldThrow();
279			} catch (NullPointerException success) {}
280	dl	1.4	}
281
282			/**
283	jsr166	1.23	* getBlocker returns the blocker object passed to park
284	dl	1.3	*/
285	jsr166	1.23	public void testGetBlocker_parkBlocker() {
286			testGetBlocker(ParkMethod.parkBlocker);
287			}
288			public void testGetBlocker_parkNanosBlocker() {
289			testGetBlocker(ParkMethod.parkNanosBlocker);
290			}
291			public void testGetBlocker_parkUntilBlocker() {
292			testGetBlocker(ParkMethod.parkUntilBlocker);
293			}
294			public void testGetBlocker(final ParkMethod parkMethod) {
295			final CountDownLatch started = new CountDownLatch(1);
296	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
297	jsr166	1.12	public void realRun() {
298	jsr166	1.23	Thread t = Thread.currentThread();
299			started.countDown();
300			do {
301			assertNull(LockSupport.getBlocker(t));
302			parkMethod.park();
303			assertNull(LockSupport.getBlocker(t));
304			// park may return spuriously
305	jsr166	1.28	} while (! Thread.interrupted());
306	jsr166	1.11	}});
307
308	jsr166	1.23	long startTime = System.nanoTime();
309			await(started);
310			for (;;) {
311			Object x = LockSupport.getBlocker(t);
312			if (x == theBlocker()) { // success
313			t.interrupt();
314			awaitTermination(t);
315			assertNull(LockSupport.getBlocker(t));
316			return;
317			} else {
318			assertNull(x); // ok
319			if (millisElapsedSince(startTime) > LONG_DELAY_MS)
320			fail("timed out");
321			Thread.yield();
322			}
323			}
324	dl	1.1	}
325
326	dl	1.3	/**
327	jsr166	1.23	* timed park(0) returns immediately.
328			*
329			* Requires hotspot fix for:
330			* 6763959 java.util.concurrent.locks.LockSupport.parkUntil(0) blocks forever
331			* which is in jdk7-b118 and 6u25.
332	dl	1.3	*/
333	jsr166	1.23	public void testPark0_parkNanos() {
334			testPark0(ParkMethod.parkNanos);
335			}
336			public void testPark0_parkUntil() {
337			testPark0(ParkMethod.parkUntil);
338			}
339			public void testPark0_parkNanosBlocker() {
340			testPark0(ParkMethod.parkNanosBlocker);
341			}
342			public void testPark0_parkUntilBlocker() {
343			testPark0(ParkMethod.parkUntilBlocker);
344			}
345			public void testPark0(final ParkMethod parkMethod) {
346	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
347	jsr166	1.12	public void realRun() {
348	jsr166	1.23	parkMethod.park(0L);
349	jsr166	1.15	}});
350
351	jsr166	1.23	awaitTermination(t);
352	jsr166	1.15	}
353
354			/**
355	jsr166	1.23	* timed park(Long.MIN_VALUE) returns immediately.
356	jsr166	1.20	*/
357	jsr166	1.23	public void testParkNeg_parkNanos() {
358			testParkNeg(ParkMethod.parkNanos);
359			}
360			public void testParkNeg_parkUntil() {
361			testParkNeg(ParkMethod.parkUntil);
362			}
363			public void testParkNeg_parkNanosBlocker() {
364			testParkNeg(ParkMethod.parkNanosBlocker);
365			}
366			public void testParkNeg_parkUntilBlocker() {
367			testParkNeg(ParkMethod.parkUntilBlocker);
368	jsr166	1.20	}
369	jsr166	1.23	public void testParkNeg(final ParkMethod parkMethod) {
370	jsr166	1.16	Thread t = newStartedThread(new CheckedRunnable() {
371	jsr166	1.15	public void realRun() {
372	jsr166	1.23	parkMethod.park(Long.MIN_VALUE);
373	jsr166	1.11	}});
374
375	jsr166	1.21	awaitTermination(t);
376	dl	1.1	}
377			}