JSR-166 update

Adapted from sources taken from CVS using: 
cvs -d ':pserver:anonymous@gee.cs.oswego.edu/home/jsr166/jsr166' checkout -D "03/03/2016 10:00:00 GMT" jsr166

Bug: 27426599
Change-Id: Ic9ba278929f8747d58b69e7d67ec325064588bff

1 files changed, 884 insertions, 0 deletions

diff --git a/jsr166-tests/src/test/java/jsr166/StampedLockTest.java b/jsr166-tests/src/test/java/jsr166/StampedLockTest.java
new file mode 100644
index 0000000000..d347c7d67e
--- /dev/null
+++ b/jsr166-tests/src/test/java/jsr166/StampedLockTest.java
@@ -0,0 +1,884 @@
+/*
+ * 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/
+ */
+
+package jsr166;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.StampedLock;
+
+import junit.framework.Test;
+import junit.framework.TestSuite;
+
+public class StampedLockTest extends JSR166TestCase {
+    // android-note: Removed because the CTS runner does a bad job of
+    // retrying tests that have suite() declarations.
+    //
+    // public static void main(String[] args) {
+    //     main(suite(), args);
+    // }
+    // public static Test suite() {
+    //     return new TestSuite(StampedLockTest.class);
+    // }
+
+    /**
+     * A runnable calling writeLockInterruptibly
+     */
+    class InterruptibleLockRunnable extends CheckedRunnable {
+        final StampedLock lock;
+        InterruptibleLockRunnable(StampedLock l) { lock = l; }
+        public void realRun() throws InterruptedException {
+            lock.writeLockInterruptibly();
+        }
+    }
+
+    /**
+     * A runnable calling writeLockInterruptibly that expects to be
+     * interrupted
+     */
+    class InterruptedLockRunnable extends CheckedInterruptedRunnable {
+        final StampedLock lock;
+        InterruptedLockRunnable(StampedLock l) { lock = l; }
+        public void realRun() throws InterruptedException {
+            lock.writeLockInterruptibly();
+        }
+    }
+
+    /**
+     * Releases write lock, checking isWriteLocked before and after
+     */
+    void releaseWriteLock(StampedLock lock, long s) {
+        assertTrue(lock.isWriteLocked());
+        lock.unlockWrite(s);
+        assertFalse(lock.isWriteLocked());
+    }
+
+    /**
+     * Constructed StampedLock is in unlocked state
+     */
+    public void testConstructor() {
+        StampedLock lock;
+        lock = new StampedLock();
+        assertFalse(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+    }
+
+    /**
+     * write-locking and read-locking an unlocked lock succeed
+     */
+    public void testLock() {
+        StampedLock lock = new StampedLock();
+        assertFalse(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+        long s = lock.writeLock();
+        assertTrue(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+        lock.unlockWrite(s);
+        assertFalse(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+        long rs = lock.readLock();
+        assertFalse(lock.isWriteLocked());
+        assertTrue(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 1);
+        lock.unlockRead(rs);
+        assertFalse(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+    }
+
+    /**
+     * unlock releases either a read or write lock
+     */
+    public void testUnlock() {
+        StampedLock lock = new StampedLock();
+        assertFalse(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+        long s = lock.writeLock();
+        assertTrue(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+        lock.unlock(s);
+        assertFalse(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+        long rs = lock.readLock();
+        assertFalse(lock.isWriteLocked());
+        assertTrue(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 1);
+        lock.unlock(rs);
+        assertFalse(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+    }
+
+    /**
+     * tryUnlockRead/Write succeeds if locked in associated mode else
+     * returns false
+     */
+    public void testTryUnlock() {
+        StampedLock lock = new StampedLock();
+        assertFalse(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+        long s = lock.writeLock();
+        assertTrue(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+        assertFalse(lock.tryUnlockRead());
+        assertTrue(lock.tryUnlockWrite());
+        assertFalse(lock.tryUnlockWrite());
+        assertFalse(lock.tryUnlockRead());
+        assertFalse(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+        long rs = lock.readLock();
+        assertFalse(lock.isWriteLocked());
+        assertTrue(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 1);
+        assertFalse(lock.tryUnlockWrite());
+        assertTrue(lock.tryUnlockRead());
+        assertFalse(lock.tryUnlockRead());
+        assertFalse(lock.tryUnlockWrite());
+        assertFalse(lock.isWriteLocked());
+        assertFalse(lock.isReadLocked());
+        assertEquals(lock.getReadLockCount(), 0);
+    }
+
+    /**
+     * write-unlocking an unlocked lock throws IllegalMonitorStateException
+     */
+    public void testWriteUnlock_IMSE() {
+        StampedLock lock = new StampedLock();
+        try {
+            lock.unlockWrite(0L);
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
+    }
+
+    /**
+     * write-unlocking an unlocked lock throws IllegalMonitorStateException
+     */
+    public void testWriteUnlock_IMSE2() {
+        StampedLock lock = new StampedLock();
+        long s = lock.writeLock();
+        lock.unlockWrite(s);
+        try {
+            lock.unlockWrite(s);
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
+    }
+
+    /**
+     * write-unlocking after readlock throws IllegalMonitorStateException
+     */
+    public void testWriteUnlock_IMSE3() {
+        StampedLock lock = new StampedLock();
+        long s = lock.readLock();
+        try {
+            lock.unlockWrite(s);
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
+    }
+
+    /**
+     * read-unlocking an unlocked lock throws IllegalMonitorStateException
+     */
+    public void testReadUnlock_IMSE() {
+        StampedLock lock = new StampedLock();
+        long s = lock.readLock();
+        lock.unlockRead(s);
+        try {
+            lock.unlockRead(s);
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
+    }
+
+    /**
+     * read-unlocking an unlocked lock throws IllegalMonitorStateException
+     */
+    public void testReadUnlock_IMSE2() {
+        StampedLock lock = new StampedLock();
+        try {
+            lock.unlockRead(0L);
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
+    }
+
+    /**
+     * read-unlocking after writeLock throws IllegalMonitorStateException
+     */
+    public void testReadUnlock_IMSE3() {
+        StampedLock lock = new StampedLock();
+        long s = lock.writeLock();
+        try {
+            lock.unlockRead(s);
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
+    }
+
+    /**
+     * validate(0) fails
+     */
+    public void testValidate0() {
+        StampedLock lock = new StampedLock();
+        assertFalse(lock.validate(0L));
+    }
+
+    /**
+     * A stamp obtained from a successful lock operation validates
+     */
+    public void testValidate() throws InterruptedException {
+        StampedLock lock = new StampedLock();
+        long s = lock.writeLock();
+        assertTrue(lock.validate(s));
+        lock.unlockWrite(s);
+        s = lock.readLock();
+        assertTrue(lock.validate(s));
+        lock.unlockRead(s);
+        assertTrue((s = lock.tryWriteLock()) != 0L);
+        assertTrue(lock.validate(s));
+        lock.unlockWrite(s);
+        assertTrue((s = lock.tryReadLock()) != 0L);
+        assertTrue(lock.validate(s));
+        lock.unlockRead(s);
+        assertTrue((s = lock.tryWriteLock(100L, MILLISECONDS)) != 0L);
+        assertTrue(lock.validate(s));
+        lock.unlockWrite(s);
+        assertTrue((s = lock.tryReadLock(100L, MILLISECONDS)) != 0L);
+        assertTrue(lock.validate(s));
+        lock.unlockRead(s);
+        assertTrue((s = lock.tryOptimisticRead()) != 0L);
+    }
+
+    /**
+     * A stamp obtained from an unsuccessful lock operation does not validate
+     */
+    public void testValidate2() throws InterruptedException {
+        StampedLock lock = new StampedLock();
+        long s;
+        assertTrue((s = lock.writeLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertFalse(lock.validate(lock.tryWriteLock()));
+        assertFalse(lock.validate(lock.tryWriteLock(10L, MILLISECONDS)));
+        assertFalse(lock.validate(lock.tryReadLock()));
+        assertFalse(lock.validate(lock.tryReadLock(10L, MILLISECONDS)));
+        assertFalse(lock.validate(lock.tryOptimisticRead()));
+        lock.unlockWrite(s);
+    }
+
+    /**
+     * writeLockInterruptibly is interruptible
+     */
+    public void testWriteLockInterruptibly_Interruptible()
+            throws InterruptedException {
+        final CountDownLatch running = new CountDownLatch(1);
+        final StampedLock lock = new StampedLock();
+        long s = lock.writeLock();
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                running.countDown();
+                lock.writeLockInterruptibly();
+            }});
+
+        running.await();
+        waitForThreadToEnterWaitState(t, 100);
+        t.interrupt();
+        awaitTermination(t);
+        releaseWriteLock(lock, s);
+    }
+
+    /**
+     * timed tryWriteLock is interruptible
+     */
+    public void testWriteTryLock_Interruptible() throws InterruptedException {
+        final CountDownLatch running = new CountDownLatch(1);
+        final StampedLock lock = new StampedLock();
+        long s = lock.writeLock();
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                running.countDown();
+                lock.tryWriteLock(2 * LONG_DELAY_MS, MILLISECONDS);
+            }});
+
+        running.await();
+        waitForThreadToEnterWaitState(t, 100);
+        t.interrupt();
+        awaitTermination(t);
+        releaseWriteLock(lock, s);
+    }
+
+    /**
+     * readLockInterruptibly is interruptible
+     */
+    public void testReadLockInterruptibly_Interruptible()
+            throws InterruptedException {
+        final CountDownLatch running = new CountDownLatch(1);
+        final StampedLock lock = new StampedLock();
+        long s = lock.writeLock();
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                running.countDown();
+                lock.readLockInterruptibly();
+            }});
+
+        running.await();
+        waitForThreadToEnterWaitState(t, 100);
+        t.interrupt();
+        awaitTermination(t);
+        releaseWriteLock(lock, s);
+    }
+
+    /**
+     * timed tryReadLock is interruptible
+     */
+    public void testReadTryLock_Interruptible() throws InterruptedException {
+        final CountDownLatch running = new CountDownLatch(1);
+        final StampedLock lock = new StampedLock();
+        long s = lock.writeLock();
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                running.countDown();
+                lock.tryReadLock(2 * LONG_DELAY_MS, MILLISECONDS);
+            }});
+
+        running.await();
+        waitForThreadToEnterWaitState(t, 100);
+        t.interrupt();
+        awaitTermination(t);
+        releaseWriteLock(lock, s);
+    }
+
+    /**
+     * tryWriteLock on an unlocked lock succeeds
+     */
+    public void testWriteTryLock() {
+        final StampedLock lock = new StampedLock();
+        long s = lock.tryWriteLock();
+        assertTrue(s != 0L);
+        assertTrue(lock.isWriteLocked());
+        long s2 = lock.tryWriteLock();
+        assertEquals(s2, 0L);
+        releaseWriteLock(lock, s);
+    }
+
+    /**
+     * tryWriteLock fails if locked
+     */
+    public void testWriteTryLockWhenLocked() {
+        final StampedLock lock = new StampedLock();
+        long s = lock.writeLock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                long ws = lock.tryWriteLock();
+                assertTrue(ws == 0L);
+            }});
+
+        awaitTermination(t);
+        releaseWriteLock(lock, s);
+    }
+
+    /**
+     * tryReadLock fails if write-locked
+     */
+    public void testReadTryLockWhenLocked() {
+        final StampedLock lock = new StampedLock();
+        long s = lock.writeLock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                long rs = lock.tryReadLock();
+                assertEquals(rs, 0L);
+            }});
+
+        awaitTermination(t);
+        releaseWriteLock(lock, s);
+    }
+
+    /**
+     * Multiple threads can hold a read lock when not write-locked
+     */
+    public void testMultipleReadLocks() {
+        final StampedLock lock = new StampedLock();
+        final long s = lock.readLock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                long s2 = lock.tryReadLock();
+                assertTrue(s2 != 0L);
+                lock.unlockRead(s2);
+                long s3 = lock.tryReadLock(LONG_DELAY_MS, MILLISECONDS);
+                assertTrue(s3 != 0L);
+                lock.unlockRead(s3);
+                long s4 = lock.readLock();
+                lock.unlockRead(s4);
+            }});
+
+        awaitTermination(t);
+        lock.unlockRead(s);
+    }
+
+    /**
+     * A writelock succeeds only after a reading thread unlocks
+     */
+    public void testWriteAfterReadLock() throws InterruptedException {
+        final CountDownLatch running = new CountDownLatch(1);
+        final StampedLock lock = new StampedLock();
+        long rs = lock.readLock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                running.countDown();
+                long s = lock.writeLock();
+                lock.unlockWrite(s);
+            }});
+
+        running.await();
+        waitForThreadToEnterWaitState(t, 100);
+        assertFalse(lock.isWriteLocked());
+        lock.unlockRead(rs);
+        awaitTermination(t);
+        assertFalse(lock.isWriteLocked());
+    }
+
+    /**
+     * A writelock succeeds only after reading threads unlock
+     */
+    public void testWriteAfterMultipleReadLocks() {
+        final StampedLock lock = new StampedLock();
+        long s = lock.readLock();
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                long rs = lock.readLock();
+                lock.unlockRead(rs);
+            }});
+
+        awaitTermination(t1);
+
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                long ws = lock.writeLock();
+                lock.unlockWrite(ws);
+            }});
+
+        assertFalse(lock.isWriteLocked());
+        lock.unlockRead(s);
+        awaitTermination(t2);
+        assertFalse(lock.isWriteLocked());
+    }
+
+    /**
+     * Readlocks succeed only after a writing thread unlocks
+     */
+    public void testReadAfterWriteLock() {
+        final StampedLock lock = new StampedLock();
+        final long s = lock.writeLock();
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                long rs = lock.readLock();
+                lock.unlockRead(rs);
+            }});
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                long rs = lock.readLock();
+                lock.unlockRead(rs);
+            }});
+
+        releaseWriteLock(lock, s);
+        awaitTermination(t1);
+        awaitTermination(t2);
+    }
+
+    /**
+     * tryReadLock succeeds if readlocked but not writelocked
+     */
+    public void testTryLockWhenReadLocked() {
+        final StampedLock lock = new StampedLock();
+        long s = lock.readLock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                long rs = lock.tryReadLock();
+                threadAssertTrue(rs != 0L);
+                lock.unlockRead(rs);
+            }});
+
+        awaitTermination(t);
+        lock.unlockRead(s);
+    }
+
+    /**
+     * tryWriteLock fails when readlocked
+     */
+    public void testWriteTryLockWhenReadLocked() {
+        final StampedLock lock = new StampedLock();
+        long s = lock.readLock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                long ws = lock.tryWriteLock();
+                threadAssertEquals(ws, 0L);
+            }});
+
+        awaitTermination(t);
+        lock.unlockRead(s);
+    }
+
+    /**
+     * timed tryWriteLock times out if locked
+     */
+    public void testWriteTryLock_Timeout() {
+        final StampedLock lock = new StampedLock();
+        long s = lock.writeLock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                long startTime = System.nanoTime();
+                long timeoutMillis = 10;
+                long ws = lock.tryWriteLock(timeoutMillis, MILLISECONDS);
+                assertEquals(ws, 0L);
+                assertTrue(millisElapsedSince(startTime) >= timeoutMillis);
+            }});
+
+        awaitTermination(t);
+        releaseWriteLock(lock, s);
+    }
+
+    /**
+     * timed tryReadLock times out if write-locked
+     */
+    public void testReadTryLock_Timeout() {
+        final StampedLock lock = new StampedLock();
+        long s = lock.writeLock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                long startTime = System.nanoTime();
+                long timeoutMillis = 10;
+                long rs = lock.tryReadLock(timeoutMillis, MILLISECONDS);
+                assertEquals(rs, 0L);
+                assertTrue(millisElapsedSince(startTime) >= timeoutMillis);
+            }});
+
+        awaitTermination(t);
+        assertTrue(lock.isWriteLocked());
+        lock.unlockWrite(s);
+    }
+
+    /**
+     * writeLockInterruptibly succeeds if unlocked, else is interruptible
+     */
+    public void testWriteLockInterruptibly() throws InterruptedException {
+        final CountDownLatch running = new CountDownLatch(1);
+        final StampedLock lock = new StampedLock();
+        long s = lock.writeLockInterruptibly();
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                running.countDown();
+                lock.writeLockInterruptibly();
+            }});
+
+        running.await();
+        waitForThreadToEnterWaitState(t, 100);
+        t.interrupt();
+        assertTrue(lock.isWriteLocked());
+        awaitTermination(t);
+        releaseWriteLock(lock, s);
+    }
+
+    /**
+     * readLockInterruptibly succeeds if lock free else is interruptible
+     */
+    public void testReadLockInterruptibly() throws InterruptedException {
+        final CountDownLatch running = new CountDownLatch(1);
+        final StampedLock lock = new StampedLock();
+        long s;
+        s = lock.readLockInterruptibly();
+        lock.unlockRead(s);
+        s = lock.writeLockInterruptibly();
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                running.countDown();
+                lock.readLockInterruptibly();
+            }});
+
+        running.await();
+        waitForThreadToEnterWaitState(t, 100);
+        t.interrupt();
+        awaitTermination(t);
+        releaseWriteLock(lock, s);
+    }
+
+    /**
+     * A serialized lock deserializes as unlocked
+     */
+    public void testSerialization() {
+        StampedLock lock = new StampedLock();
+        lock.writeLock();
+        StampedLock clone = serialClone(lock);
+        assertTrue(lock.isWriteLocked());
+        assertFalse(clone.isWriteLocked());
+        long s = clone.writeLock();
+        assertTrue(clone.isWriteLocked());
+        clone.unlockWrite(s);
+        assertFalse(clone.isWriteLocked());
+    }
+
+    /**
+     * toString indicates current lock state
+     */
+    public void testToString() {
+        StampedLock lock = new StampedLock();
+        assertTrue(lock.toString().contains("Unlocked"));
+        long s = lock.writeLock();
+        assertTrue(lock.toString().contains("Write-locked"));
+        lock.unlockWrite(s);
+        s = lock.readLock();
+        assertTrue(lock.toString().contains("Read-locks"));
+    }
+
+    /**
+     * tryOptimisticRead succeeds and validates if unlocked, fails if locked
+     */
+    public void testValidateOptimistic() throws InterruptedException {
+        StampedLock lock = new StampedLock();
+        long s, p;
+        assertTrue((p = lock.tryOptimisticRead()) != 0L);
+        assertTrue(lock.validate(p));
+        assertTrue((s = lock.writeLock()) != 0L);
+        assertFalse((p = lock.tryOptimisticRead()) != 0L);
+        assertTrue(lock.validate(s));
+        lock.unlockWrite(s);
+        assertTrue((p = lock.tryOptimisticRead()) != 0L);
+        assertTrue(lock.validate(p));
+        assertTrue((s = lock.readLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryOptimisticRead()) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockRead(s);
+        assertTrue((s = lock.tryWriteLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertFalse((p = lock.tryOptimisticRead()) != 0L);
+        lock.unlockWrite(s);
+        assertTrue((s = lock.tryReadLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryOptimisticRead()) != 0L);
+        lock.unlockRead(s);
+        assertTrue(lock.validate(p));
+        assertTrue((s = lock.tryWriteLock(100L, MILLISECONDS)) != 0L);
+        assertFalse((p = lock.tryOptimisticRead()) != 0L);
+        assertTrue(lock.validate(s));
+        lock.unlockWrite(s);
+        assertTrue((s = lock.tryReadLock(100L, MILLISECONDS)) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryOptimisticRead()) != 0L);
+        lock.unlockRead(s);
+        assertTrue((p = lock.tryOptimisticRead()) != 0L);
+    }
+
+    /**
+     * tryOptimisticRead stamp does not validate if a write lock intervenes
+     */
+    public void testValidateOptimisticWriteLocked() {
+        StampedLock lock = new StampedLock();
+        long s, p;
+        assertTrue((p = lock.tryOptimisticRead()) != 0L);
+        assertTrue((s = lock.writeLock()) != 0L);
+        assertFalse(lock.validate(p));
+        assertFalse((p = lock.tryOptimisticRead()) != 0L);
+        assertTrue(lock.validate(s));
+        lock.unlockWrite(s);
+    }
+
+    /**
+     * tryOptimisticRead stamp does not validate if a write lock
+     * intervenes in another thread
+     */
+    public void testValidateOptimisticWriteLocked2()
+            throws InterruptedException {
+        final CountDownLatch running = new CountDownLatch(1);
+        final StampedLock lock = new StampedLock();
+        long s, p;
+        assertTrue((p = lock.tryOptimisticRead()) != 0L);
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.writeLockInterruptibly();
+                running.countDown();
+                lock.writeLockInterruptibly();
+            }});
+
+        running.await();
+        assertFalse(lock.validate(p));
+        assertFalse((p = lock.tryOptimisticRead()) != 0L);
+        t.interrupt();
+        awaitTermination(t);
+    }
+
+    /**
+     * tryConvertToOptimisticRead succeeds and validates if successfully locked,
+     */
+    public void testTryConvertToOptimisticRead() throws InterruptedException {
+        StampedLock lock = new StampedLock();
+        long s, p;
+        s = 0L;
+        assertFalse((p = lock.tryConvertToOptimisticRead(s)) != 0L);
+        assertTrue((s = lock.tryOptimisticRead()) != 0L);
+        assertTrue((p = lock.tryConvertToOptimisticRead(s)) != 0L);
+        assertTrue((s = lock.writeLock()) != 0L);
+        assertTrue((p = lock.tryConvertToOptimisticRead(s)) != 0L);
+        assertTrue(lock.validate(p));
+        assertTrue((s = lock.readLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryConvertToOptimisticRead(s)) != 0L);
+        assertTrue(lock.validate(p));
+        assertTrue((s = lock.tryWriteLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryConvertToOptimisticRead(s)) != 0L);
+        assertTrue(lock.validate(p));
+        assertTrue((s = lock.tryReadLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryConvertToOptimisticRead(s)) != 0L);
+        assertTrue(lock.validate(p));
+        assertTrue((s = lock.tryWriteLock(100L, MILLISECONDS)) != 0L);
+        assertTrue((p = lock.tryConvertToOptimisticRead(s)) != 0L);
+        assertTrue(lock.validate(p));
+        assertTrue((s = lock.tryReadLock(100L, MILLISECONDS)) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryConvertToOptimisticRead(s)) != 0L);
+        assertTrue(lock.validate(p));
+    }
+
+    /**
+     * tryConvertToReadLock succeeds and validates if successfully locked
+     * or lock free;
+     */
+    public void testTryConvertToReadLock() throws InterruptedException {
+        StampedLock lock = new StampedLock();
+        long s, p;
+        s = 0L;
+        assertFalse((p = lock.tryConvertToReadLock(s)) != 0L);
+        assertTrue((s = lock.tryOptimisticRead()) != 0L);
+        assertTrue((p = lock.tryConvertToReadLock(s)) != 0L);
+        lock.unlockRead(p);
+        assertTrue((s = lock.writeLock()) != 0L);
+        assertTrue((p = lock.tryConvertToReadLock(s)) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockRead(p);
+        assertTrue((s = lock.readLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryConvertToReadLock(s)) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockRead(p);
+        assertTrue((s = lock.tryWriteLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryConvertToReadLock(s)) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockRead(p);
+        assertTrue((s = lock.tryReadLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryConvertToReadLock(s)) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockRead(p);
+        assertTrue((s = lock.tryWriteLock(100L, MILLISECONDS)) != 0L);
+        assertTrue((p = lock.tryConvertToReadLock(s)) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockRead(p);
+        assertTrue((s = lock.tryReadLock(100L, MILLISECONDS)) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryConvertToReadLock(s)) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockRead(p);
+    }
+
+    /**
+     * tryConvertToWriteLock succeeds and validates if successfully locked
+     * or lock free;
+     */
+    public void testTryConvertToWriteLock() throws InterruptedException {
+        StampedLock lock = new StampedLock();
+        long s, p;
+        s = 0L;
+        assertFalse((p = lock.tryConvertToWriteLock(s)) != 0L);
+        assertTrue((s = lock.tryOptimisticRead()) != 0L);
+        assertTrue((p = lock.tryConvertToWriteLock(s)) != 0L);
+        lock.unlockWrite(p);
+        assertTrue((s = lock.writeLock()) != 0L);
+        assertTrue((p = lock.tryConvertToWriteLock(s)) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockWrite(p);
+        assertTrue((s = lock.readLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryConvertToWriteLock(s)) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockWrite(p);
+        assertTrue((s = lock.tryWriteLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryConvertToWriteLock(s)) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockWrite(p);
+        assertTrue((s = lock.tryReadLock()) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryConvertToWriteLock(s)) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockWrite(p);
+        assertTrue((s = lock.tryWriteLock(100L, MILLISECONDS)) != 0L);
+        assertTrue((p = lock.tryConvertToWriteLock(s)) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockWrite(p);
+        assertTrue((s = lock.tryReadLock(100L, MILLISECONDS)) != 0L);
+        assertTrue(lock.validate(s));
+        assertTrue((p = lock.tryConvertToWriteLock(s)) != 0L);
+        assertTrue(lock.validate(p));
+        lock.unlockWrite(p);
+    }
+
+    /**
+     * asWriteLock can be locked and unlocked
+     */
+    public void testAsWriteLock() {
+        StampedLock sl = new StampedLock();
+        Lock lock = sl.asWriteLock();
+        lock.lock();
+        assertFalse(lock.tryLock());
+        lock.unlock();
+        assertTrue(lock.tryLock());
+    }
+
+    /**
+     * asReadLock can be locked and unlocked
+     */
+    public void testAsReadLock() {
+        StampedLock sl = new StampedLock();
+        Lock lock = sl.asReadLock();
+        lock.lock();
+        lock.unlock();
+        assertTrue(lock.tryLock());
+    }
+
+    /**
+     * asReadWriteLock.writeLock can be locked and unlocked
+     */
+    public void testAsReadWriteLockWriteLock() {
+        StampedLock sl = new StampedLock();
+        Lock lock = sl.asReadWriteLock().writeLock();
+        lock.lock();
+        assertFalse(lock.tryLock());
+        lock.unlock();
+        assertTrue(lock.tryLock());
+    }
+
+    /**
+     * asReadWriteLock.readLock can be locked and unlocked
+     */
+    public void testAsReadWriteLockReadLock() {
+        StampedLock sl = new StampedLock();
+        Lock lock = sl.asReadWriteLock().readLock();
+        lock.lock();
+        lock.unlock();
+        assertTrue(lock.tryLock());
+    }
+
+}