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root/jsr166/jsr166/src/jsr166e/extra/AtomicDouble.java

Comparing jsr166/src/jsr166e/extra/AtomicDouble.java (file contents):
Revision 1.3 by jsr166, Tue Aug 9 08:28:54 2011 UTC vs.
Revision 1.4 by jsr166, Tue Aug 9 19:10:29 2011 UTC

#	Line 39 | Line 39 | public class AtomicDouble extends Number
39		private static final sun.misc.Unsafe unsafe = getUnsafe();
40		private static final long valueOffset;
41
42	–	/**
43	–	* Records whether the underlying JVM supports lockless
44	–	* compareAndSwap for longs. While the Unsafe.compareAndSwapLong
45	–	* method works in either case, some constructions should be
46	–	* handled at Java level to avoid locking user-visible locks.
47	–	*/
48	–	static final boolean VM_SUPPORTS_LONG_CAS = VMSupportsCS8();
49	–
50	–	/**
51	–	* Returns whether underlying JVM supports lockless CompareAndSet
52	–	* for longs. Called only once and cached in VM_SUPPORTS_LONG_CAS.
53	–	*/
54	–	private static boolean VMSupportsCS8() {
55	–	final Class<?> klazz = java.util.concurrent.atomic.AtomicLong.class;
56	–	return java.security.AccessController.doPrivileged
57	–	(new java.security.PrivilegedAction<Boolean>() {
58	–	public Boolean run() {
59	–	try {
60	–	java.lang.reflect.Method m =
61	–	klazz.getDeclaredMethod("VMSupportsCS8", new Class<?>[0]);
62	–	m.setAccessible(true);
63	–	return (Boolean) m.invoke(new Class<?>[0]);
64	–	} catch (Throwable t) { throw new Error(t); }
65	–	}});
66	–	}
67	–
42		static {
43		try {
44		valueOffset = unsafe.objectFieldOffset

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